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The absolute marginal fit of CAD-CAM presintered fixed partial dentures has been poorly documented.The purpose of this in vitro study was to evaluate the marginal fit of presintered cobalt-chromium (Co-Cr) and zirconia 3-unit fixed partial dentures by using X-ray microcomputed tomography (μCT).A metal model was prepared from a typodont to receive fixed partial dentures (N=12). The maxillary first premolar and first molar were prepared with a circumferential 1.2-mm chamfer and 2-mm occlusal reduction. The dies were scanned and assigned to 1 of 2 groups to receive the prostheses made of presintered Co-Cr or presintered zirconia (n=6). Each framework was seated on its model without load application. The abutments were scanned by using μCT. A circle with 10 diameters, with a step of 18 degrees, was projected at the center of the obtained image. Absolute marginal discrepancy and marginal gap mean values were measured, and overextended and underextended margins determined. The data were analyzed by using the Levene t test and ANOVA (α=.05).No statistically significant difference was found in the marginal fit between the materials tested (P=.939). The mean values were 66 ±14 μm for Co-Cr and 61 ±12 μm for zirconia. The absolute marginal discrepancy mean value for the premolar was 69 ±12 μm and 41 ±9 μm for the molar (P.001). Overextension was predominant for both materials tested, with a higher percentage reported for the zirconia group.Presintered alloys presented clinically acceptable adaptation with a predominance of marginal overextensions.

INTRODUCTION This study aimed to investigate the effects of the strong occlusal force on the hemodynamics of gingival microcirculation. METHODS Eleven adult volunteers with healthy periodontium and normal occlusion participated in this study. Using a noncontact laser Doppler flowmeter placed at the attached gingiva and the interdental papilla of the maxillary first premolar, changes in gingival blood flow (GBF) were examined during and after clenching. RESULTS When the strong occlusal pressure was applied on the maxillary first premolar by clenching, GBF in the attached gingiva on the buccal side decreased significantly compared with the resting GBF, with medians of 2.3 mL/min/100 g and 5.4 mL/min/100 g, respectively (P

To evaluate and compare the influence of dissimilar CAD-CAM material on the marginal fitness of endocrown with different cavity depths. Freshly extracted human maxillary first premolar teeth (n = 40) were selected for this study. Teeth were decapitated 2 mm above the cement-enamel junction from proximal surface and endodontic treatment were performed for all teeth. Samples were allocated at two main groups (n = 20), according to cavity depth. Group A: 2 mm cavity depth; Group B: 4 mm cavity depth; and further subdivided into two sub-groups according to material used (n = 10): (A1 and B1) resin-based material; (A2 and B2) ceramic-based material. Teeth were prepared with butt joint margin and 10° internal axial wall divergence. Afterwards, samples scanning was performed using InLab digital scanner. Endocrown restoration fabricated by Sirona Cerec InLab MCXL milling device and adhesively luted with a resin cement (RelyX™ Ultimate ClickerTM, 3 M ESPE). All samples were subjected to thermocycling. After thermocycling, marginal gaps were measured using stereomicroscope at a magnification of 45X. The recorded measurements were collected, scaled and statistically analyzed. A resin-based endocrown showed significantly a smaller vertical marginal gap than ceramic-based, an endocrown with 2-mm cavity depth showed significantly lower marginal gap than one with 4-mm cavity depth. Increasing the cavity depth of endocrown preparation negatively affect the marginal fit. Resin-nanoceramic endocrown showed better marginal fit than glass ceramic endocrown. Both tested CAD/CAM materials showed clinically acceptable vertical marginal gap.

A variety of shapes has been reported for the roots and root canals of maxillary first premolars. The purposes of the present study were to determine branching and shapes of the roots of maxillary first premolars, as well as age-related changes using slice images obtained with cone-beam computed tomography (CBCT) for dental use. CBCT-reconstructed images of 125 cases that included maxillary first premolars were used as subjects. Slice images at the cervical one-third, center, and apical one-third positions of the root were prepared. Root branching and number of root canals was determined at each measurement position in the images. The subjects were divided into three groups: younger than 30 years, 30 to 50 years, and over 50 years. The root canal morphology was compared among these age groups. Single-rooted premolars were the most frequent. As for number of root canals, a single-canal premolar was observed at the position of the cervical one-third in 33.6%, at the center in 35.2%, and at the apical one-third in 56.0%. Thereafter the subjects were divided into groups by age, namely, younger than 30 years, 30 to 50 years, and over 50 years old, and it was revealed that the ratio of the two-canal type increased with age. In regard to tooth morphology, it was confirmed that the two-canal type shows more frequent occurrence with aging in maxillary first premolar. Based on our findings, we consider that CBCT can be useful for determining the root canal morphology with complicated shapes.

Made available in DSpace on 2022-04-29T08:35:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2021-01-01 Extrusion of sodium hypochlorite (NaOCl) is a very rare accident with the most common complications including pain, swelling, and hematoma. It can occur even if procedural guidelines, predisposing conditions, and risk factors are taken into consideration. A 59-year-old female patient was admitted to the endodontics department to treat a left maxillary first premolar (World Dental Federation tooth 24). The medical history included osteoporosis and systemic medication with alendronate. Initially, the diagnosis was “symptomatic irreversible pulpitis” with “normal apical tissues.” During instrumentation of the buccal canal, accidental extrusion of 2.5% NaOCl occurred into the periapical tissues, resulting from misinterpretation of the working length, and caused severe pain and bleeding. The canal was immediately flushed using copious irrigation with saline solution. An analgesic and corticosteroid were prescribed. At 3 and 7 days, ecchymosis and slight hematoma were observed extraorally in the area of the affected tooth and an intraoral ulceration at the apex of the affected tooth. At 15 days, minimal signs of ecchymosis were observed, and the treatment was resumed. At 30 days after the accident, there was complete remission of the sequelae. The clinical, radiographic, and tomographic assessment after 1 month, 1 year, and 8 years showed favorable case evolution. During the 8-year follow-up, the patient maintained the systemic use of alendronate. It can be concluded that NaOCl extrusion is an accident that causes patients and clinicians to experience an unpleasant consequence. The radiographic working length should always be determined carefully. A successful outcome can be achieved in patients who take alendronate. Department of Restorative Dentistry Araraquara School of Dentistry São Paulo State University Department of Endodontics Cayetano Heredia Peruvian University Department of Restorative Dentistry Araraquara School of Dentistry São Paulo State University

Objective The aim of this study was to evaluate the influence of different marginal designs (deep chamfer, vertical, and modified vertical with reverse shoulder) on the fracture strength and failure modes of monolithic zirconia crowns. Materials and Methods Thirty sound human maxillary first premolar teeth with comparable size were used in this study. The teeth were divided randomly into three groups according to the preparation design (n = 10): (1) group A: teeth prepared with a deep chamfer finish line; (2) group B: teeth prepared with vertical preparation; and (3) group C: teeth prepared with modified vertical preparation, where a reverse shoulder of 1 mm was placed on the buccal surface at the junction of middle and occlusal thirds. All samples were scanned by using an intraoral scanner (CEREC Omnicam, Sirona, Germany), and then the crowns were designed by using Sirona InLab 20.0 software and milled with a 5-axis machine. Each crown was then cemented on its respective tooth with self-adhesive resin cement by using a custom-made cementation device. A single load to failure test was used to assess the fracture load of each crown by using a computerized universal testing machine that automatically recorded the fracture load of each sample in Newton (N). Statistical Analysis The data were analyzed statistically by using one-way analysis of variance test and Bonferroni test at a level of significance of 0.05. Results The highest mean of fracture load was recorded by chamfer (2,969.8 N), which followed by modified vertical (2,899.3 N) and the lowest mean of fracture load was recorded by vertical (2,717.9 N). One-way ANOVA test revealed a significant difference among the three groups. Bonferroni test showed a significant difference between group A and group B, while a nonsignificant difference was revealed between group C with group A and group B. Conclusion Within the limitations of this in vitro study, the mean values of fracture strength of monolithic zirconia crowns of all groups were higher than the maximum occlusal forces in the premolar region. The modification of the vertical preparation with a reverse shoulder placed at the buccal surface improved the fracture strength up to the point that it was statistically nonsignificant with the chamfer group.

Background: Dental anomalies usually lead to complicated decisions having to be made in terms of the orthodontic treatment of permanent dentition; tooth rotation is the most common of these irregularities. The prevalence rate of this phenomenon is 2.1–5.1% in patients who have not received orthodontic treatment. Purpose: This case report aimed to manage the complete bilateral rotation of maxillary canines with couple force by using a Nance appliance modification. Case: A 17-year-old male patient came in wanting to straighten his teeth. He complained about his bilateral canines, which were not in a normal position. There was an impacted left maxillary second premolar and an ectopically erupted right maxillary first premolar. He also had protrusions in the upper and lower anterior teeth and crowding in the lower anterior teeth as well as upper and lower midline deviations. Case Management: A clinical examination showed a class I relationship between the dental and cephalometry measurements and highlighted a class I skeletal pattern. The upper right first premolar was extracted and the left second premolar had undergone an odontectomy to allay protrusion and correct crowding. Bilaterally rotated upper canines were derotated using a modified Nance appliance and an elastomeric chain with couple force. Conclusion: The success of the orthodontic treatment was influenced by the specific nature of the patient’s dental and medical history, extraoral and intraoral examination, diagnosis and treatment planning, which was followed by a systematic approach to treatment . The Nance appliance modification reduced the total treatment time by achieving controlled anchorage and derotation of the canines.

Aims: The main goal of the following case report was to shed the light on the importance of thorough clinical, radiological and histological examinations in order to elaborate a final diagnosis of asymptomatic dentigerous cysts detected in unusual locations. Presentation of Case: A case of dentigerous cyst was identified accidentally in the maxillary left premolar region of an asymptomatic 14-year-old female post an orthodontic consultation. Histological examination of the tissue specimens following enucleation confirmed the diagnosis of a dentigerous cyst. Discussion: Dentigerous cysts are the second most common odontogenic cysts after radicular cysts. They involve impacted, un-erupted, permanent, supernumerary, odontomas and rarely deciduous teeth. Dentigerous cysts are usually painless but may cause facial swelling and delayed tooth eruption. Extensive maxillary involvement and childhood presentation are rare. Radio-graphic and histological examinations should be done to confirm the diagnosis of a dentigerous cyst. Conclusion: In our case, we showed the presence of a maxillary premolar dentigerous cyst that was removed by enucleation. The presence of dentigerous cyst is not always associated with a syndrome and its removal is very important to avoid future complications.

Background: During canine retraction, orthodontic forces are applied away from the tooth’s center of resistance. This introduces canine distal tipping and mesiobuccal rotation. The correction of these unwanted movements will prolong treatment time. Applying the force closer to the center of resistance should decrease this unwanted tooth movement. Objective: Compare the canine angulation and rotation during canine retraction with and without the use of power arm. Materials and Methods: Twenty-four female orthodontic patients (age 19.32± 4.17 years) with dental Class II indicated for bilateral maxillary first premolar extraction and maximum anchorage were included in this study. The canines were retracted with elastomeric chains over 0.016” X 0.022” statinless steel arch wires to reduce friction. The retraction force was 150g. In twelve patients, the canines were retracted using a power arm fixed to the vertical slots of the canine brackets. For the other twelve patients, the elastic chains were attached to the bracket hooks. Results: Before treatment, the canine angulation and rotation was similar for the two groups. The canine angulation was 12.38± 8.27 and 14.5o± 9.41 for the group with the power arm and without, respectively. while canine rotation was 64.74o± 11.65 and 63.12o± 14.88, respectively. Post-retraction, there was no significant difference in the canine angulation or rotation between the groups. Conclusion: Compared to canine retraction with a power arm, conventional canine retraction with elastomeric chains attached to the bracket hook may provide similar control over distal tipping, provided a stiff 0.017” X 0.025” stainless steel arch wire is used.

Objective: To determine the frequency of the number of roots and root canals in a sample of 250 extracted maxillary first premolar teeth of patients visiting Peshawar Dental College and Hospital Khyber Pakhtunkhwa. Study Design: Cross Sectional. Setting: Department of Oral Biology, Peshawar Dental College and Hospital Khyber Pakhtunkhwa. Period: April 2016 to December 2016. Material & Methods: A total of 250 extracted human maxillary first premolars were collected from the Department of Oral & Maxillofacial Surgery, Peshawar Dental College, and Hospital Khyber Pakhtunkhwa. All teeth were visually inspected to count the number of roots. Subsequently, the access cavity was prepared, and pulp extirpated from each tooth. Endodontic explorer was used to locating the canal orifice(s) at the pulp chamber floor. Later the root canal orifices were injected with India ink to stain the canals. After that roots of teeth were sectioned at different levels to note down the number of canals. Data were analyzed using SPSS version 19. The statistical significance of the variations from mean values was considered significant if the p-value was less than 0.05. Results: Out of 250 maxillary first premolar teeth, 44.8% had one root, 40.4% had two separate and 12.8% had two fused roots. Three roots were seen in 2.0% teeth. Two root canals were present in the vast majority (70.4%), whereas one and three root canals were seen in 27.6% and 2.0% teeth, respectively. The correlation between the number of roots and root canals of maxillary first premolar teeth was highly significant. Conclusions: There was a high frequency of maxillary first premolars with two roots and two root canals.

Objective To assess the rate of tooth movement and the periodontal tissue status over a period of 90 days with and without micro-osteoperforation (MOP). Method Thirty-three adults of the 19 to 25 age group undergoing labial fixed orthodontic treatment with bilateral maxillary first premolar extraction, requiring individual canine retraction as a part of the treatment plan, were recruited for this split-mouth randomized clinical trial. While performing micro-implant–assisted canine retraction in the maxillary arch, the experimental side received three MOPs each on the mesial and distal aspects of the canine root. The amount of tooth movement was measured clinically at every 15 days interval for 90 days; the periodontal status was assessed clinically (probing depth, relative attachment level) and tomographically (canine root length, alveolar bone level) at the 1st day and 90th day of retraction. The data were subjected to appropriate statistical analyses. Results A statistically significant difference in tooth movement on the MOP side was observed in the first 45 days, amounting to 1.5 times more than that of the control side. However, during 45 to 90 days, the difference in the rate of tooth movement between the sides was not statistically significant. Changes in periodontal variables were also insignificant between the sides except for the distal alveolar bone level. Conclusion An increase in the rate of tooth movement can be achieved without any periodontal adverse effects in the first 45 days of the MOP procedure. The effectiveness of the MOP procedure on the rate of tooth movement gradually declined thereafter. Trial Registration: CTRI/2019/07/020403.

Objectives: to evaluate possible cytotoxic effects of titanium alloy (Ti alloy) orthodontic mini-screw implants on the surrounding oral mucosal cells. Materials and Methods: Thirty orthodontic mini-screw implants (MSIs) installed to serve as anchorage for maxillary canine retraction after maxillary first premolar extraction. Fifteen female orthodontic patients with mean age of 16.11 ± 1.68 years were consented to participate in the study, which ran for four months. The orthodontic appliance consisted of direct-bonded Roth monocrystalline ceramic brackets, and teflon-coated preformed archwires. Clinical evaluation of MSIs and oral hygiene condition were evaluated throughout the study period. Percentage of oral mucosa cells’ DNA fragmentation were analyzed before insertion of MSIs, after one week, one month, three months and four months of MSIs insertion with the Comet assay analysis. Results: ANOVA test showed statistically significant decrease in oral hygiene condition during the study period. Statistically insignificant difference was evident in DNA fragmentation index of the collected oral mucosal cell in different time intervals. Conclusions: Orthodontic titanium alloy MSIs were biocompatible and demonstrated no cytotoxic effects on oral mucosal cells.

The computer-aided design/computer-aided manufacturing (CAD/CAM) virtual orthodontic system produces customized brackets, indirect bonding jigs, and archwires based on a three-dimensional virtual setup. In surgical cases, this system helps to visualize the final occlusion during diagnosis and to efficiently plan individualized presurgical orthodontic treatments. A 20-year-old female patient with a skeletal Class III malocclusion, maxillary protrusion, and lip protrusion was successfully treated with orthognathic surgery and orthodontic treatment with maxillary first premolar extractions. The CAD/CAM system was applied for efficient treatment, with a total active treatment time of 16 months. In this case report, the applicability of the CAD/CAM virtual orthodontic system for orthognathic surgery cases is demonstrated. Suggestions are also made to overcome the limitations and to maximize the advantages of this system during orthodontic treatment of patients undergoing orthognathic surgery.

Objectives. This study is aimed at investigating the root and root canal morphology by cone beam computed tomography (CBCT) and palatal furcation groove of the buccal root by microcomputed tomography (micro-CT) of maxillary first premolars in a Chinese subpopulation. Methods. This study assessed CBCT images of 440 patients aged 14-80 years. Based on Vertucci’s classification, the number of roots and the canal configuration were determined. Forty-eight maxillary first premolars with furcation grooves were analyzed by micro-CT in patients aged 18-25 years. Results. Based on the CBCT assay, 70.22% and 29.32% of maxillary first premolars were 1 root and 2 roots, respectively. The configuration indicated statistical difference ( P < 0.05 ) between male and female patients. The most common canal type was type IV and was found in 44.32% of cases, followed by type I in 27.84%, and then type II in 20.57%. Root bifurcations had 40.13% prevalence which was distributed more in the middle third than in the cervical and the apical third. For the micro-CT study, 95.83% of the furcation groove configuration was found in the bifurcated maxillary first premolars. The length varied from 1.02 to 7.63 mm. The mean depth of this groove was 0.57 mm in the root coronal, 0.47 mm in the root middle, and 0.22 mm in the root apical level. Palatal dentin width was smaller than 1 mm. Conclusion. The anatomy of the root and root canal system and the irregular wall width of maxillary first premolars with furcation grooves may help dentists to understand the anatomical morphology and improve the outcomes of endodontic treatment.

Fusion is a developmental dental anomaly in which asingle large tooth is formed from the germs of two normally adjacentteeth. The incidence of fused teeth is 0.1-0.3% in the permanent and0.5-2.5% in the primary dentition, and fusion is usually unilateral. Anot her dental developmental anomaly, dens evaginatus, is defined as anaccessory tubercle, consisting of enamel, dentine, and pulp. A 17-year old female patient was referred to our clinic with a complaint of painand swelling in the maxilla bilateral premolar regions. After the eva luation of clinical, two, and three-dimensional radiological findings,bilateral complete and incomplete fusion of the maxillary first premo lar and impacted supernumerary teeth was diagnosed, which is a rarecondition. Also, the left impacted supernumerary tooth had another de velopmental anomaly, dens evaginatus, that makes the case more inte resting. Treatment options were recommended to the patient, whorequested the extraction of the teeth, and the relevant teeth were ext racted. Careful clinical and radiographic examinations should be per formed for the diagnosis and treatment of fusion that may causefunctional and esthetic problems.

Introduction This single-centered, parallel-groups trial aimed to evaluate the efficacy of traditional corticotomy vs flapless corticotomy in accelerating en-masse retraction. In addition, to assess the skeletal, dental, and soft-tissue variables, as well as the external apical root resorption (EARR) of the maxillary anterior teeth. Methods Forty patients with Class II Division 1 malocclusion aged >18 years at the beginning of treatment, requiring maxillary first premolar extractions, were randomly distributed into 2 groups (n = 20 each): 1 group was treated using traditional corticotomy, and the other group was treated with flapless corticotomy in en-masse retraction with anchorage based on miniscrews placed between maxillary second premolars and first molars bilaterally. Randomization was implemented with a computer-generated list of random numbers; allocation was concealed in sequentially numbered, opaque, sealed envelopes. The study was single-blinded (outcomes' assessor). The primary outcome was the en-masse retraction duration. Secondary outcomes were the skeletal, dental, and soft-tissue changes on lateral cephalometric and the EARR of maxillary anterior teeth on digital panoramic radiographs. Results The en-masse retraction duration in the flapless corticotomy group was longer than the traditional corticotomy group. The average retraction duration was 4.04 ± 1.10 months for the flapless corticotomy group and 3.75 ± 2.14 months for the traditional corticotomy group, with no significant difference between the 2 groups (95% confidence interval [CI], −0.81 to 1.39; P = 0.59). No significant differences were observed between the 2 groups regarding changes in several lateral cephalometric variables (eg, SNA angle [95% CI, −2.55° to 1.66°; P = 0.67], SN-U1 angle [95% CI, −1.70° to 1.32°; P = 0.80], and UL-E [95% CI: −1.33 to 1.00 mm; P = 0.78]) or in the amount of EARR in the maxillary anterior teeth (P = 0.31). The proportion of the observed EARR ranged from 1% to 6% of root length in both corticotomy groups. No serious harms were observed in both groups. Conclusions No significant differences between the flapless and traditional corticotomies were found in terms of the skeletal, dental, and soft-tissue variables as well as in the amount of EARR. Corticotomy-assisted en-masse retraction led to improvements in skeletal structures and facial profile and resulted in sufficient retraction of maxillary anterior teeth, slight distal movement of maxillary first molars, and an intrusion movement for both anterior and posterior teeth. Both corticotomy techniques did not cause significant EARR. Registration ClinicalTrials.gov (Identifier: NCT03279042 ). Protocol The protocol was not published before the trial commencement.

Introduction The aims and objectives of this study were to evaluate the von Mises stress and principal stress distribution and displacement of anterior teeth in a lingual orthodontics system along the periodontal ligament and alveolar bone by various combinations of mini-implants and lever arm during en-masse retraction. Four 3-dimensional finite element (FE) models of the bilateral maxillary first premolar extraction cases were constructed. Methods Lingual brackets were (0.018-in slots) positioned over the center of the clinical crown. In all 4 models, 150 g of retraction force was applied with the help of a nickel-titanium closed coil spring with different combinations of mini-implants and lever arm on each side. FE analysis was then performed to evaluate stress distribution, principal stress, von Mises stress, and displacement of the anterior teeth using ANSYS software (version 12.1; Ansys, Canonsburg, Pa). The FE study was enough to validate the analysis results obtained by software tools with FE simulation instead of experimental readings. Thus, statistical analysis was not required. Results In this study, maximum tensile stresses were observed in the periodontal ligament at the mesial cervical region of the canine with values of 1.84 MPa, 2.02 MPa, 1.88 MPa, and 2.08 MPa for models 1-4, respectively. Maximum von Mises stress in alveolar bone was 8.05 MPa, 8.23 MPa, 8.19 MPa, and 8.37 MPa for models 1-4, respectively, which was within the optimum limit (135 MPa). Variable amounts of displacements like lingual crown tipping, lingual root tipping, and extrusion were observed in all the models. The 15-mm long lever arm models (models 2 and 4) showed a more controlled crown (0.015 mm) and root movement (0.004 mm) compared with 12-mm long lever arm models (models 1 and 3). Conclusions In lingual orthodontics, controlled root movement increased as we increased the length of the lever arm. It was also concluded that the amount of increased controlled tipping found with the placement of the mini-implant was toward the palatal slope.

BACKGROUND: Clinicians routinely provide provisional crowns following teeth preparation. Three-dimensional (3D) printing technology could be used over conventional methods for better fit as lack of adequate fit would result in plaque accumulation, micro-leakage, teeth sensitivity, caries and periodontal diseases. OBJECTIVE: The aim of the study was to evaluate the marginal and internal fit of provisional crowns fabricated using 3D printing technology and to compare it with that of compression molding and milling methods. METHODS: Ninety study models were fabricated by duplicating metal master models of the maxillary first premolar molar with three different finish line chamfer, rounded shoulder and rounded shoulder with bevel. On each study model, provisional crowns were fabricated using compression molding (Mo. group, n= 30 – by over impression technique), milling (Mi. group, n= 30 – by 5-axis dental milling machine), and 3D printing method (3D-P. group, n= 30 – by 3D printer). Marginal and internal fit of the samples were evaluated by measuring gap using a scanning electron microscope with a magnification of 27 ×, at 7 zones A–G on different finish line models. The data were statistically analysed using one-way analysis of variance (ANOVA) at the 0.05 significance level. The p-values were calculated using Dunnett’s test. RESULTS: The marginal gap was minimal for the 3D-P. group for each finish line with lowest for rounded shoulder with bevel at zone A 30.6 ± 5.3 and at zone G 32.8 ± 5.4. In axial area, i.e. zones B and F, the minimum gap was noticed for the Mo. group and in Occlusal area (cusp and fossa), for zones C–E maximum gap was determined in Mi. group followed by Mo. and 3D-P. groups. CONCLUSIONS: 3D printed provisional crowns have better marginal and internal fit compared to milled and molded provisional crowns.

Introduction. Inadequate root canal preparation and obturation are potential causes of endodontic failure. Failed root canal treatment with intrinsic discoloration requires root canal re-treatment and intracoronal bleaching. Due to the extensive loss of hard tissues on occlusal area, the restoration requires intracanal retention with short fiber-reinforced composite. Case report. A 17-year-old male patient came to the Clinic of Conservative Dentistry Dental Hospital Prof. Soedomo. He reported pain and discomfort on maxillary first premolar while chewing after root canal procedure had been performed few months before. He felt unconvinience with the discoloration happened on those tooth. Patient had endodontic treatment one year ago and the tooth was restored with glass ionomer cement. Objective examination showed glass ionomer restoration was still in good condition, the tooth was sensitive to percussion but not to palpation, and showed no mobility. Periapical radiograph showed incomplete obturation with radioluscent around periapical region. Retreatment followed by intracoronal bleaching was performed under rubber dam isolation. Tooth was restored with short fiber reinforced composite and composite resin. After 3 month, patient was recalled for examine the previous sign and symptomps. Periapical radiograph showed diameter of periapical lesion was smaller and tooth functioned normally. Conclusion. Root canal retreatment and intracoronal bleaching are suitable options for teeth with failed root canal treatment and intrinsic discoloration

This case report is of a 31-year-old female who presented with splinted and faulty metalloceramic prosthesis on maxillary anterior teeth, which was responsible for localised periodontal disease and poor aesthetics. At multiple sites the ceramic had chipped off and the prosthesis colour did not match with the adjacent healthy teeth. A multidisciplinary approach of endodontics, periodontics and prosthodontics was employed for this case. The treatment plan consisted of removing the faulty prosthesis, endodontic retreatment of inadequately root-treated teeth and endodontics in the other coronally prepared abutment teeth. Crown lengthening surgery was performed for the correction of periodontal pockets and high smile line and maintenance of an adequate biological width. After periodontal healing, all-ceramic individual crowns were placed on the maxillary anterior teeth along with a three-unit all-ceramic bridge for the replacement of the left upper maxillary first premolar. The final results were aesthetically pleasing with good marginal fit. The patient was extremely satisfied with the outcome as all her concerns were addressed. It is, therefore, advisable to consider placing individual crowns rather than multiunit splinted prosthesis whenever possible.

OBJECTIVES The purpose of this in vitro study was to compare the effect of simulated endodontic access preparation on the failure loads of lithium disilicate crowns and resin-matrix ceramic (RMC) crowns. MATERIALS AND METHODS Eighty maxillary first premolar crowns were manufactured by using four different CAD/CAM blocks (n = 20): lithium disilicate (LD; IPS e.max CAD), resin nanoceramic (RNC; Lava Ultimate), flexible nanaoceramic (FNC; GC Cerasmart), and polymer-infiltrated ceramic (PIC; VITA Enamic). Half of each group was accessed and repaired to simulate endodontic treatment. After cyclic loading, all specimens were loaded to failure. Data were analyzed with two-way ANOVA followed by Tukey-HSD test (α = .05). RESULTS The load to failure results showed significant differences for material types (P

To evaluate the changes of maxillary expansion and upper airway structure after microimplant assisted rapid palatal expansion (MARPE) using cone-beam computed tomography (CBCT).This retrospective study included 19 subjects (15 females and 4 males) aged 15-29 years old (mean, 19.95±4.39 years) with maxillary transverse deficiency treated with MARPE. CBCT was performed at the initial diagnosis and 3 months after MARPE treatment. Measurements were taken to evaluate the amount of total expansion, skeletal expansion, and dental expansion at the maxillary first premolar (P1), second premolar (P2), first molar (M1), second molar (M2) regions and upper airway changes.After MARPE treatment, the maxillary skeletal base expansion, skeletal expansion, alveolar expansion and dental expansion were achieved at the P1, P2, M1, M2 region. The nasopharyngeal volume significantly increased 8.48% after MARPE treatment compared with that before the treatment (P 0.05). The change of nasal lateral width (NLW) was also significantly different before and after MARPE (P 0.05). However, there were no statistically significant change in the oropharyngeal, palatopharyngeal, glossopharyngeal and airway total volume (all P 0.05).MARPE can produce more transverse bone expansion, relieve maxillary transverse deficiency and improve upper airway ventilation.

Introduction: Orthodontic treatment of class II division 1 malocclusion by extracting the maxillary first premolar causes vertical dimensional change is still a matter of debate. The purpose of this research was to determine the vertical changes of the lower anterior facial height and maxillary incisor vertical dimensions in class II division 1 malocclusion after orthodontic treatment with Edgewise technique. Materials and Methods: This study was conducted on the cephalometry of 24 patients before and after orthodontic treatment with inclusion criteria as follows: Angle Class II division 1 malocclusion, aged 18-30 years old. Measurements were taken for the lower anterior facial height (ANS - Me) and maxillary incisor vertical dimensions by performing an Upper Anterior Dental Height (UADH). Data analysis used was the Wilcoxon test for unpaired data. Results: The result of p-value = 0.195 > 0.05 for lower anterior face height showed no significant difference; and p-value = 0.878 > 0.05 for UADH also showed no significant difference. Conclusion: Orthodontic treatment for class II division 1 malocclusion with the removal of two premolars does not change the lower anterior facial height and maxillary incisor vertical dimensions.

Aim and objective To evaluate the marginal adaptation at the tooth-restoration interface at enamel and cementum margins using composite restoration reinforced with novel enamel inserts/biofillers. Materials and methods Standardized class V box-shaped cavities were prepared in 40 extracted maxillary first premolar teeth which were divided randomly into four experimental groups consisting of 10 samples each. Group I: Bulk placement. Groups II: Horizontal incremental technique. Group III: Restoration with precured composite balls (megafillers). Group IV: Restoration with biofillers. All the cavities were restored with visible light-activated direct restorative nanocomposite. The specimens were thermocycled for 24 hours. After thermocycling, the samples were immersed in a 1% methylene blue for 4 hours and subsequently evaluated for microleakage. Microleakage scores (0–4) were obtained from gingival margins of class V restorations and analyzed by statistical analysis. Evaluation of the data was performed by Kruskal–Wallis one-way analysis of variance (ANOVA), and Mann–Whitney U tests. Results Microleakage scores have indicated restorations with biofillers showed best results followed by megafillers, incremental horizontal build-up, and bulk filling. Conclusion Biofillers provide a novel approach in improving microleakage and marginal adaptability of composite resin restorations. Clinical significance Incorporation of inserts, which are capable of adequate bonding to resin and tooth, may provide improved marginal adaptability and reduce microleakage around restorative margins. How to cite this article Biradar N, Allappanavar KS, Shetty NK, et al. Evaluation of Marginal Adaptation of Composite Restorations Reinforced with Novel Enamel Inserts (Biofillers) in Class V Cavities. J Contemp Dent Pract 2020;21(12):1368–1373.

Aims In premolars and molars, transverse ridge (TR) and oblique ridge (OR) play major roles in providing strength and stability to the cusps in particular and tooth as a whole. Hence, they could be divided at the central groove or the transverse groove in a divine golden ratio. Materials and methods Twenty pairs of maxillary and mandibular casts were retrieved from the Department of Orthodontics. The lengths of buccal triangular ridge (BTR), lingual triangular ridge (LTR) and TR of maxillary and mandibular first and second premolars were measured. Similarly, lengths of distal cuspal ridge of mesiopalatal cusp, triangular ridge of distobuccal cusp (DBTR) and OR of the maxillary first and second molars were measured using a brass wire and a Vernier caliper. The TR:BTR, BTR:LTR, OR:distal ridge of mesiopalatal cusp (MPDR), and MPDR:DBTR ratios were calculated to find out the possibility of golden ratio. Results Transverse ridges of the premolars and OR of the maxillary first and second molars were divided at the central groove in a divine golden ratio. The mean TR/BTR ratio for maxillary first premolar was 1.61 ± 0.007, whereas the mean BTR/LTR ratio was 1.63 ± 0.02. The mean TR/BTR ratio for maxillary second premolar was 1.61 ± 0.01, whereas the mean BTR/LTR ratio was 1.62 ± 0.04. The TR/BTR and BTR/LTR ratios for mandibular first premolar were 1.6 ± 0.008 and 1.64 ± 0.02, respectively. Similarly, the mean TR/BTR ratio for mandibular second premolar was 1.61 ± 0.01, whereas the mean BTR/LTR ratio was 1.63 ± 0.02. Conclusion The ORs of maxillary first molar ridge and TR of maxillary and mandibular premolars are divided into two parts at transverse and central grooves, respectively, in a divine ratio. Clinical relevance The ORs of maxillary first molar ridge and TR of maxillary and mandibular premolars are divided into two parts at transverse and central grooves, respectively, in a divine ratio. This signifies the strength and stability of the occlusal table in the posterior teeth, as the golden ratio is the mark of functional excellence. Golden ratio should be taken into consideration while restoration or fabrication of the posterior teeth.

Background: Dimension and location of pulp chamber are important during access cavity preparation. It allows clinician in instruments selection, orientation and depth of cutting dur­ing the process. Analysis of these has been done in preoperative intraoral periapical radio­graph that gives two-dimensional image. The radiograph has been blamed now and then for the inaccurate results and iatrogenic damage occurred due to the inaccurate results. Cone-Beam Computed Tomography (CBCT) provides three-dimensional images and is taken as standard. Hence the aim of the study is to compare intra-oral periapical (IOPA) radiograph and CBCT to determine the landmarks for accurate results Methods: 50 intact two-rooted maxillary first premolars were collected and numbered. Peri­apical radiograph Images and CBCT images of these 50 teeth were taken and divided as; Group I: 50 IOPAR and Group II: 50 CBCT images. Landmarks marking and measurement was done using tracing paper and x-ray viewer for IOPA images and Planmeca Romexis software for CBCT images. Data were collected and analysed with descriptive and inferential statistics by using Statistical Package of Social Science (SPSS) software version 16. Results: The averages of group I are 7.44, 10.23mm 14.33mm, 4.1mm, 6.89mm and 2.79mm respectively. The averages of in group II are 6.95mm, 9.58mm, 14.03mm, 4.45mm, 7.07mm and 2.63mm respectively. There is statistically significant difference in measurement A and measurement B between group I and group II. Conclusions: This indicates that there are chances of overestimation of measurement A and B with IOPAR.

Objective To date, there is no clear consensus in the literature which endocrown design with which material is the most effective treatment option to restore endodontically treated maxillary premolars with extensive loss of tooth structure. The aim of this study was to evaluate the stress distribution pattern and failure probability of maxillary first premolars restored with a novel endocrown system compared to the conventional one by means of Finite Element and Weibull analyses. Materials and methods Two finite element (FE) models representing two endocrown systems used for restoration of severely-destructed endodontically treated maxillary first premolar tooth were generated: model C for the conventional monolithic IPS e.max CAD endocrown and model P for the novel bi-layered endocrown (PEKKTON ivory coping veneered with cemented IPS e.max CAD). A static occlusal compressive load was axially and centrally-applied. Modified von Mises and maximum principal stress values on the remaining tooth structure, cement lines and restorative materials were evaluated separately. Weibull function was incorporated with FE analysis to calculate the long term failure probability. Results Regarding stresses occurred in the remaining tooth structure (enamel and dentin), model P transmitted less stresses than model C. The individual enamel of model C showed about 5% and 40% risk of failure at normal and maximum occlusal load values, respectively, while for model P, it had no failure risk at both values. For dentin, model C showed about 13% failure risk at the normal masticatory force, while model P showed only 2%. At clenching value, model C dentin showed about 44% failure risk, while only 9% was resulted for model P. Conclusions Compared to the conventional endocrown system, the positive impact of the studied novel endocrown system on the stress distribution pattern and also on the survival/failure probability of the restored severely-destructed endodontically treated maxillary first premolar teeth was reflected (more tooth-friendly), not only at normal masticatory forces but also at the maximum functional loads. Clinical significance The novel endocrown system using a PEKK coping veneered with cemented IPS e.max CAD can be considered a favorable option for restoration of severely-destructed endodontically treated premolar teeth, with more protection for residual tooth structure. Despite the conventional endocrown system may benefit the durability of tooth bonding, it should not be selected for restoration of clenching cases because of the too high overall failure risk.

Background The objective of this study was to use CBCT to look into the root canal morphology of maxillary premolars in a Saudi Arabian subpopulation and associate the results to existing canal morphology classifications. Methods The sample size for this analysis was 500 right and left untreated maxillary first and second premolars with fully formed roots from 250 Saudi residents (125 male and 125 female). The following observations were made using CBCT on the teeth related: (1) The number and morphology of roots; (2) The canal morphology for each root according to Vertucci's classification. The frequency and similarities between the right and left sides, as well as between females and males, were studied. The Chi-square test was used to assess the results. Results Of the 500 maxillary first premolars studied, 199 teeth had one root (39.8%), whilst 293 (58.6%) were two-rooted. Three-rooted maxillary first premolars were found in 8 (1.6%). For maxillary second premolars, 416 premolars had one root (83.2%), whilst 79 (15.8%) had two roots and the rest 5 (1.0%) were three roots. There were significant differences of number of root were found between groups (p > 0.05). For maxillary first premolar, Type IV was the most frequent, accounting for 57.8% of the sample (n = 289), followed by type II (32.8%, n = 164). For maxillary second premolar, Type I was mainly occurrence 302 (60.4%), followed by Type II (16.4%, n = 82). Conclusions The majority of maxillary first premolars had two roots and two root canals, while one root and one root canal was the most common anatomical configuration for maxillary second premolars. Additional canal forms do occur on occasion, and clinicians should pay close attention to them.

Summary Introduction This randomized controlled clinical trial aimed to assess the effect of LED 5 and LLLT 6 in a three-arm parallel setting. Methods Sixty patients who needed the maxillary first premolar extraction were allocated to three groups using the stratified block randomization method. In the LED group, a custom-made device with a wavelength of 640 nm and a power density of 40 mW/cm2 was used 5 min/day. In the laser group, Ga Al As 7 laser with a wavelength of 810 nm and a power of 100 mW was used on days 0, 3, 30, and 60 each time for 18 seconds. Patients in the control group received placebo treatment as the laser group protocol, using a coated light cure device. Models were made at baseline and monthly until the end of the retraction. The rate of canine retraction was the primary outcome, while canine rotation and pain were secondary outcomes. The final data were anonymous for the outcome assessor and statistical consultant. Data were analyzed per protocol using a linear mixed model. Results The rate of canine retraction significantly increased by 60.8% in the laser group, while it increased not significantly by 26% in the LED group compared with the control group. There was no significant difference among the groups in terms of tooth rotation and pain. Conclusions LLLT can accelerate orthodontic tooth movement (OTM). LED with the present setting couldn’t increase the rate of OTM. LLLT and LED did not affect canine rotation or pain. Trial registration IRCT20120220009086N4. On 1 June 2019 was retrospectively registered.

Summary Aim Acceleration of orthodontic tooth movement (OTM) can decrease the rate of complications. This study aimed to assess the efficacy of micro-osteoperforation (MOP) of the alveolar bone for acceleration of OTM by using mini-screws. Materials and methods This split-mouth randomized clinical trial evaluated 25 patients (11 females, 14 males, 16–25 years) with class II division I malocclusion who required canine retraction following the extraction of maxillary first premolar. The patients received similar orthodontic treatment at both sides with MOP on one side (MOP group) and no MOP on the other side (control side). Allocation of MOP to the side of jaw was random using Random Allocation Software in 1:1 distribution and equal numbers. Blinding was not applicable. The rate of canine movement was measured monthly for 5 months and considered as the main outcome. The degree of canine tipping was measured at the end of the intervention as the secondary outcome. All measurements were repeated for 12 patients by the two observers and the intra- and inter-examiner correlation coefficients were found to be 0.946 and 0.925, respectively. Data were analysed by paired t-test and repeated measures ANOVA. Results Twenty-five patients (11 females, 14 males, 16–25 years) were evaluated. No significant difference was found between the two groups at different time points in the rate of canine movement (P > 0.05). The degree of canine tipping in the MOP group was significantly lower than that in the control group (5.34 ± 3.11° versus 7.08 ± 3.70°; P = 0.040). Gender had no significant effect on OTM in any group (P > 0.05). Conclusions MOP could not accelerate canine retraction but decreased the degree of canine tipping.

The aim of this study is to investigate the effect of photobiomodulation therapies on root resorption compared with the placebo group. Thirty patients who were admitted to the Gaziantep University Faculty of Dentistry Orthodontics Department for treatment, with an indication of upper right first premolar tooth extraction were included. Before the individuals’ orthodontic treatment, 0.022 slot MBT brackets and tubes were placed on the maxillary first premolar and molar. A 150-g buccal tipping force was applied to the first premolar. Cantilever spring with 0.017 × 0.025 Beta Titanium wire was used for force application. Individuals were then randomly divided into three groups. For the first group, laser application was performed with an 810-nm GaAlAs laser device at 0, 3, 7, 14, 21, and 28 days to 8 J/cm2. For the second group, an LED application according to the manufacturer’s instructions with an 850-nm wavelength and 20 mW/cm2 output power for 10 min per day during the experiment. For the third group, a placebo therapy was completed whereby a laser device that did not make active pulses was used. At the end of 4 weeks, the amount of root surface resorption was compared using micro-CT imaging after the extraction of the teeth. No significant difference was found between the groups in terms of regional and total crater volumes. It was observed that photobiomodulation therapies were not different from the control group in terms of forming root resorption. It is seen that laser and LED photobiomodulation therapies used for accelerate orthodontic tooth movement do not differ from the control group in terms of forming root resorption. According to the results of this pilot study on this subject, which needs to be clarified with new findings in the future, LED and laser applications may not increase the risk for root resorption.

The purpose of this study was to investigate the expansion of the maxillary sinus and the inclinations of posterior teeth in orthodontic patients with maxillary second premolar agenesis. A total of 30 subjects with one or two congenitally missing maxillary second premolars and retained maxillary deciduous second molars (a agenesis group) were selected and divided into a unilateral agenesis group (20 subjects with one maxillary second premolar missing) and a bilateral agenesis group (10 subjects with two maxillary second premolars missing). As controls, 30 sex- and age-matched subjects without agenesis of the maxillary second premolars were selected. Oblique cephalograms were used to investigate the association of maxillary second premolar agenesis and lower maxillary sinus size and posterior tooth inclinations. Agenesis of the maxillary second premolars induced significantly large lower maxillary sinus length, depth, area and mesial inclination of the maxillary first premolar, a significantly small anterior maxillary length, and a significantly more distal position for root apex of the maxillary first premolar. There were no significant differences in any measurements of the lower maxillary sinus and posterior teeth between the non-agenesis side in the unilateral agenesis group and the control group. Maxillary second premolar agenesis caused inferior and anterior expansion of the lower maxillary sinus and the mesial inclination of the maxillary first premolars with a distal position of root apex. Unilateral agenesis of the maxillary second premolar did not affect on the lower maxillary sinus size or posterior tooth inclinations of the unaffected antimere.

In the application of scientific human skeletal variation in medico-legal matters, virtual anthropology is the current technique performed to examine skeleton and its body parts. Digital imaging techniques are used in many areas of dentistry and forensic dentistry. Among all digital imaging modalities, digital periapical radiography (PR) are the most widely used, however, new contemporary imaging techniques micro-computed tomography (Micro-CT) can be also used. The aim of this study was to assess the accuracy and reliability of enamel and dentin thickness measurement through intra and inter-observer error analysis, and comparison was made between periapical radiographs and Micro-CT methods. In this study 15 maxillary first premolar were used which extracted for various reasons. Enamel and dentin thicknesses and maximum cervical crown widths (MCCW) of 15 premolar teeth were examined in both Micro-CT and periapical radiographs. The results obtained with the exact maximum cervical crown widths were compared Image J software version. A digital caliper was used to measure the actual MCCW of the teeth. Results exhibited no significant differences in the measurements by the intra or inter-observer error analyses. The intraclass correlation coefficients (ICC) were more than 0.95 by both intra and inter-observer error analyses. There was significant differences in the measurements by PR and Micro-CT methods. By parameters, Micro-CT showed the highest R value (0.962) with the least error in different methods and observers. In conclusion, dentin and enamel measurements by Micro-CT was highly accurate and reliable as in the conventional method (PR). Micro-CT evaluations should be recommended for implementation in the future anthropological studies especially in countries with limited source of dental data.

Age estimation in adults based on aspartic acid racemization (AAR) provides fewer errors and higher precision than that based on bone morphology for the identification of cadavers. The technique has been established in some labs as a routine method. However, as the essential requisites for the technique, a wide age range of teeth of the same type as the target tooth must be collected for calibration for each examination. We investigated whether dentin standard samples could be prepared by increasing the AAR rate via heat. Powdered dentin was prepared from a maxillary first premolar (13 years) and heated for 0-72 h at 110 °C. The extent of AAR increased significantly with heating time and the correlation was strong (r = 0.913; p 0.01). Similar results were found for a mandibular canine (24 years, r = 0.948; p 0.01) and a maxillary third molar (20 years, r = 0.944; p 0.01). We attempted to estimate the age of four maxillary first premolars of persons aged 25-58 years by using the heated samples (18 years, 12 h to 7 days). The differences between the actual and estimated ages were within ±5 years. The stability of the AAR rates in the powdered dentin during storage at 22-25 °C, 4 °C, and -30 °C was examined after 1 year and no significant changes had occurred. We were able to prepare dentin standard samples and created a calibration curve. This is a pilot study that needs to be validated before it can be used in forensic practice.

Objective: The prevalence of non-carious cervical lesions (NCCLs) has increased in the recent years, especially in the elderly population. The successful prevention and treatment of those lesions requires an understanding of the biomechanics of aged teeth. Considering the importance of such aspect, the impact of the age-related dentin deposition on the stress distribution of NCCLs was evaluated by means of finite element analysis. Material and Methods: A 2-dimensional model of a sound maxillary first premolar was created using CAD software. Two tooth geometries (sound, aged) and two lesion shapes (wedge, saucer) were simulated to the model. The mesh was built with 35,000 triangle and square elements of 0.1 mm in length. All tissues were considered isotropic, homogeneous and linear. Occlusal surfaces were loaded with 300 N for simulating normal chewing forces. The stress distribution was analyzed by a color scale and by the maximum principal stress at the cavosurface line angle. Results: The aged models presented lower stress concentration in the overall system in comparison to sound models. The sharp angle of wedge shaped lesions promoted higher stress concentration at the center of cavosurface angle, favoring the lesions progression. Conclusion: Considering the limitations of the current methodology, it is possible to conclude that aged tooth is a more compact structure that can better respond to stress loadings. This protective intrinsic mechanism should be considered when adopting preventive and restorative measures for NCCLs for the elderly.KeywordsAging; Finite element analysis; Non-carious; Cervical lesions.

Bone resorption is the cornerstone in bone remodeling affecting the rate of orthodontic tooth movement. RANKL has a direct effect on osteoclastogenesis. The aim of this study is to evaluate and compare the effect of low-level laser therapy (LLLT) and corticotomy-facilitated orthodontics (CFO) on RANKL release during orthodontic tooth movement. Twenty patients requiring orthodontic therapeutic extraction of the maxillary first premolar were randomly selected. A split-mouth study design was performed where corticotomy-facilitated orthodontics was randomly assigned to one side at the canine region (CG) before retraction, Laser group (LG) was assigned to the contralateral side using 940 nm diode laser irradiations (100 mW, 2.5 J, 3.9 J/cm2) at days 1, 3, 8, and 15. Canine retraction was done using nickel-titanium closed-coil spring applying a force of 150 g per side. Gingival crevicular fluid (GCF) samples were collected from distal surface of the canines on both sides, 1 day before the intervention treatment (T0), day 3 after the intervention (T1), and day 15 (T2). RANKL concentration levels were assessed using enzyme-linked immunosorbent assay. There was statistically significant increase in RANKL concentration levels in both groups (CG and LG) from T0 to T1, there was no statistically significant difference in concentration level from T1 o T2, but there was a statistically significant difference in RANKL concentration levels between T0 and T2 in both groups. CG and LG showed no statistically significant difference in RANKL concentration levels between them in T1 and T2. Low-level laser therapy and corticotomy-facilitated orthodontics can increase the RANKL release during orthodontic tooth movement which directly affects bone remodeling and the rate of orthodontic tooth movement.

Objective : The complex root canal anatomy is inherently colonised by microbial flora. Endodontic treatment success is always related to adequate disinfection of the root canal space, which ultimately affects the treatment outcome. A thorough understanding of the external and internal root canal anatomy by using adequately imaging modalities is essential before planning any treatment. The aim of this study was to investigate the number and morphology of the root canals of maxillary and mandibular premolars in Chennai population. Material and Methods : Full-size cone-beam computed tomographic images were randomly collected from 100 patients, resulting in a total of 200 first and 200 second maxillary premolars as well as 200 first and 200 second mandibular premolars. All the eight premolars were analysed in single patients, who underwent cone-beam computed tomography scanning during pre-operative assessment (before implant surgery, orthodontic treatment, diagnosis of dental-alveolar trauma or difficult root canal treatment). Total number of roots and root canals, frequency and correlations between men and women were recorded and statistically analysed by using chi-square tests. The root canal configurations were rated according to the Vertucci’s classification. Results : In the maxillary first premolar group (n = 200), 36.3% had 1 root, 56.7% had 2 roots and 7.0% had 3 roots, with most exhibiting a type IV canal configuration. In the maxillary second premolar group (n = 200), 60% had 1 root, 29.8% had 2 roots and 10.2% had 3 roots, with the majority of single-rooted second premolars exhibiting a type I canal configuration. In the mandibular first premolar group (n = 200), 80.5% had 1 root, 9.8% had 2 roots and 5% had 3 roots. In the mandibular second premolar group (n=200), 90.1% had 1 root, 6.4% had 2 roots and 3.5 % had 3 roots, with most exhibiting a type I canal configuration. No statistical correlation was found between number of roots, gender and tooth position. Conclusion : This cone-beam computed tomographic study confirmed previous anatomical and morphological investigations. Therefore, the possibility of additional root canals should be considered when treating premolars. Keywords: Cone-beam computed tomography; Mandibular; Maxillary; Premolar; Root canal; Morphology.

Objective The purpose of this laboratory study was to evaluate the fatigue resistance, fracture resistance and mode of failure of posterior hybrid-abutment-crown vs. hybrid-abutment with separate crown, both bonded to short titanium bases. Materials and methods Thirty-two titanium implants were embedded perpendicularly in auto-polymerizing resin. Implant-supported restorations simulating a maxillary first premolar were designed and milled using a CAD/CAM system and divided into 2 groups according to material (n = 16): zirconia (Z) and lithium disilicate (L). Each group was subdivided into two subgroups according to design (n = 8): hybrid-abutment-crown (ZS, LS) and hybrid-abutment with separate crown (ZC, LC). Each group was subjected to 1.2 million cycles of thermo-mechanical fatigue loading in a dual-axis chewing simulator at 120 N load. Surviving specimens were subjected to quasi-static loading in a universal testing machine. Mode of failure was determined under a low magnification optical microscope. Results During chewing simulation, 18.8% of zirconia and 43.8% of lithium disilicate restorations failed. The fracture resistance median values ranged from 3,730 N for group ZC, 3,400 N for group ZS, 1,295 N for group LS to 849 N for group LC. Group ZC had a statistically significant higher fracture resistance than groups LC and LS; however, it did not differ significantly from group ZS (p ≤ 0.05). Failures were seen in both titanium bases and ceramic superstructure. Conclusions Zirconia and lithium disilicate hybrid implant-supported restorations with short (3 mm) titanium bases failed in a considerable number already during chewing simulation. Therefore, despite their high fracture strength the use in the posterior region should be considered critically.

INTRODUCTION This study aimed to compare the skeletodental and soft tissue changes with total arch distalization using a modified C-palatal plate (MCPP) and maxillary first premolar extraction treatment in Class II malocclusion patients with severe overjet. SETTING AND SAMPLE POPULATION The sample consisted of 46 adult patients who had Class II Division 1 malocclusion with severe overjet; 25 of them received non-extraction treatment with MCPPs (age, 22.5 ± 7.2 years), and 21 received maxillary first premolar extraction treatment (age 23.4 ± 6.5 years). METHOD A total of 26 variables were measured on pre- and post-treatment lateral cephalograms. To evaluate the differences between pretreatment and post-treatment in each group, t tests and Wilcoxon rank-sum tests were used. To compare the amount of change between the two groups, MANOVA test was used. RESULTS The overjet was significantly reduced in the MCPP and extraction groups by 4.8 mm and 5.4 mm, respectively. However, the two groups had no significant difference in the sagittal, vertical and angular changes of the maxillary incisors. In addition, regarding soft tissue changes, the MCPP and extraction groups showed an increased nasolabial angle of 7.5° and 9.4°, decreased upper lip to the true vertical line of 1.8 mm and 2.2 mm, respectively (P

Aim: To evaluate the stress distribution along the periodontal ligament and alveolar bone by various combinations of mini-implants and lever arm used during en-masse retraction of anterior teeth using finite element method.Materialsand Methods: Four three-dimensional finite element models of the bilateral maxillary first premolar extraction casewas constructed. Lingual brackets were (0.018” slot) positioned over the center of the clinical crown. In all four models 150 g of retraction force with the help of the NiTi closed coil springs was applied with different combinations of mini-implants and lever arm. A finite element analysis was then performed to evaluate stress distribution, the principle stress, von Mises stress and displacement of the anterior teeth using ANSYS 12.1 software.Result: In this study the constructed models along with the load application were imported into ANSYS (version 12.1) software for analyzing the displacement and stress distribution corresponding to the force application. The maximum tensile stress of periodontal ligament were observed at distal root apex area of canine in all four models. Variable amount of displacements like lingual crown tipping, lingual root tipping and extrusion were observed in all the models suggesting different combinations of lever arm and mini-implants affect the direction of the tooth displacements in lingual mechanics.Conclusion: In lingual orthodontics tipping movement of crown decreases as the height of lever arm increases. It was also found that when mini-implants were placed at higher position the amount of tipping movement decreases with minimum amount of extrusion seen in central incisor and lateral incisor.

Purpose To investigate the influence of occlusal interference in dental prosthetics using finite element analysis (FEA). Materials and methods The FEA model designed for this study centered on an all-ceramic, bi-layered, fixed partial denture (FPD) retained on the maxillary first premolar and molar, with the second premolar replaced by a pontic. The surrounding structures, such as the neighboring teeth, antagonists, and periodontium, were modeled. Four different load cases were designed at occlusal interferences of 0, 8, 12, and 24 μm, loaded by a simulated bite force of 300 N. Principal and von Mise stresses, as well as strain, were evaluated for all included structures. Results For interferences of 12 and 24 μm, failure-relevant tensile stresses in the veneering layer were observed at the occlusal surfaces. Stress found in the zirconia FPD did not reach fatigue or flexural strength for any test load. Conclusion Peak tensile stress was observed in close proximity to occlusal contact points, increasing with increasing occlusal interference. The FEA results suggested that the majority of occlusal stress is absorbed by the deformation of the periodontal ligament. Framework failure caused by the simulated interferences was not expected. Surface defects may ultimately lead to failure due to fracture or chipping, especially in cases of weaker ceramics or veneering.

Introduction: This study sought to evaluate the efficacy of lasercision corticotomy for the acceleration of canine movement. Our secondary objectives were assessing the canine rotation, the rate of anchorage control, the level of pain, and the gingival index (GI). Methods: Twelve orthodontic patients (9 females and 3 males) referring to the School of Dentistry and one dental clinic from May 2019 to September 2019 participated in this split-mouth randomized clinical trial. The allocation of the test and control sides was performed by flipping a coin. The mean age of patients was 18.91±3.87 years (range 15-30 years). The treatment plan included maxillary first premolar extraction. Following the initial leveling and alignment phase, an initial impression was made. Corticotomy was carried out with the erbium, chromium-doped yttrium scandium gallium garnet (Er, Cr: YSGG) laser (3.5 W, 30 Hz, 40% air, 80% water) in one maxillary quadrant (the laser side). Canine retraction was immediately initiated following surgery using nickel-titanium closed-coil springs with 150 g force. The impression was repeated 1 month after the onset of retraction. The casts were scanned, and the distance between the canine cusp tip and the rugae line was measured to quantify the amount of anteroposterior canine movement. The molar anchorage control was also evaluated by measuring the distance between the mesial contact of the permanent first molar and the rugae line. Gingival health was evaluated using the GI. The modified McGill pain questionnaire was used to assess the level of patients' pain. Results: Lasercision corticotomy accelerated canine retraction with no adverse effect on gingival health. Anchorage loss in the posterior teeth and pain scores were not significantly different between the control and laser sides. Conclusion: Laser corticotomy can effectively accelerate canine retraction with no complications or discomfort for the patients.

Aims of Study: to evaluate and compare the retentive strength and the failure-modes of monolithic zirconiacrowns with different cement spacer thickness, cemented with two different types of luting agents.Materials and Methods: Forty sound maxillary first premolar teeth were divided into two main groups(n=20): Group A: cement spacer thickness of 80?m; Group B: cement spacer thickness of 120?m. Thegroups were further subdivided into two subgroups (n=10): (A1, B1) cemented with Panavia F2.0 resincement; (A2, B2) cemented with Riva luting plus RMGIC. All the teeth were prepared to receive monolithiczirconia crowns with the following features: (6o convergence angle, 0.8mm deep chamfer finishing line,4mm axial wall height with planar occlusal reduction). Afterwards, the teeth were scanned and the crownswere fabricated and cemented. Zirconia crowns were pulled-out along its path of insertion using universaltesting machine. Failure stresses were calculated in MPa. Failure-modes was assessed using magnifyinglens (2.5X).Results: The highest mean retentive values (in Mpa) was recorded by subgroup B1 (8.651); followed bysubgroup B2 (7.765); subgroup A1 (7.309) and subgroup A2 (6.875). Independent t-test showed a statisticallysignificant difference between A1 and B1 subgroups. Concerning the failure-mode, the majority of samplesrevealed adhesive failure between teeth and cement.Conclusion: All the tested crowns have mean retentive values within the clinically acceptable limit,increasing cement space resulted in a significant increase in the retention when Panavia F2.0 used as a lutingagent, while, it has no significant effect on the retention when RIVA luting plus was used.

Background Orthodontic treatment may result in undesirable side effects, such as root resorption and a decrease in the size of the pulp tissue which could be associated with the duration of the orthodontic treatment. Piezocision-assisted tooth movement was introduced as a minimally invasive surgical procedure to shorten orthodontic treatment time. This prospective randomized clinical trial was aimed to compare the pulp volume changes of maxillary anterior teeth after en-masse retraction with or without piezocision-assisted orthodontics. Methods Patients who required orthodontic treatment with bilateral maxillary first premolar extractions and en-masse retraction were recruited. Patients were randomly divided into extraction with piezocision, or only extraction, serving as controls. Pulp volume and root length changes of the maxillary six anterior teeth were measured and compared between the two groups using a 3-Dimensional analytical software. Paired and independent sample t-tests were used to compare within and between groups. Bivariate correlation was done between the mean change in pulp volume and its corresponding root length. The significance level was set at α = 0.05. Results A total of 23 patients were included, 12 in the piezocision, and 11 in the control group. At the end of the en-masse retraction phase, (mean = 122.74 ± 3.06 days) pulp volume was significantly decreased in all six anterior teeth in both groups (P P > 0.05). There was a statistically significant but moderate correlation only between the pulp volume change of the right canine and its root length, r = 0.44, P = 0.034. Conclusions The effect of piezocision-assisted orthodontic tooth movement on the pulp volume was comparable to the conventional orthodontic treatment. The degree of change in pulp volume does not appear to be related to the amount of root resorption. Trial registration NCT03180151. Registered December 25, 2016, retrospectively registered, https://clinicaltrials.gov/ct2/show/record/NCT03180151.

Objectives The aim of this study is to assess the stress distribution of a nanoceramic resin CAD/CAM material, Lava Ultimate (LU) and a polymer-infiltrated hybrid ceramic CAD/CAM material, Vita Enamic (VE) for enamel replacement for Nayyar core (corono-radicular dowel and core) or post-retained restoration designs of a maxillary first premolar tooth with missing palatal cusp. Materials and methods A three dimensional finite element (FE) modelof maxillary first premolar with two roots was modeled. A mesial-occlusal-distal-palatal (MODP) cavity was designed with cavity floor above cemento-enamel junction and including buccal cuspal reduction. Restoration designs consisted of Nayyar core restoration (NCR) and post-retained restoration (PRR) with a glass fiber post. Vita Enamic (VE), Lava Ultimate (LU) were used for enamel and everX Posterior was used for dentin replacement. Vertical occlusal load (100 N) was applied on a spherical solid rigid material simulating the food stuff. Von Mises (VM) and maximum principle stress values were evaluated separately for the remaining enamel, remaining dentin and restorative material in megapascal (MPa). Results The analysis of both VM and maximum principle stress values revealed that the most intense stress accumulation was in the cervical region of enamel for both designs. For VM, similar stress values were observed only in dentin. Stress analysis of restorative materials showed that everX Posterior had the highest stress accumulation. Conclusions The comparison of the two techniques showed that PRR had better stress distribution than NCR. NCR or PRR with LU or VE exhibited similar VM stress accumulation in dentin. Maximum principle stress analyses showed that PRR with LU transmitted the least stress to enamel and dentin indicating that when LU is the material of choice, post-retained restoration would be a satisfactory design. VM stress values of enamel revealed that VE absorbed the stress in itself and transferred less stress to dentin. This could point out that for the restoration of maxillary first premolar tooth with missing palatal cusp, VE may be a suitable material for NCR and PRR restoration techniques. Highlights When fiber reinforced composite is used as dentin replacement in combination with VE as enamel replacement; any technique; PRR or NCR, may be preferred in the restoration of MODP cavities of endodontically treated maxillary premolars. The clinical relevance has to be further studied in-vivo.

Alveolar bone grafting is routinely performed in repair of alveolar clefts. When the alveolar cleft is wider than 11 mm, however, the survival rate of the bone graft and prognosis are poor. Here, we describe successful orthodontic treatment using interdental distraction osteogenesis (IDO) with a tooth-tooth type distractor to reduce the width of the alveolar cleft in a patient with unilateral cleft lip and palate. The patient was a 12-year-old girl with unilateral cleft lip and palate, maxillary dentition midline deviation, congenitally missing maxillary lateral incisors, a palatally-displaced right upper first premolar, a wide alveolar cleft (20 mm), and mandibular prognathism due to maxillary hypoplasia. Treatment comprised a combination of orthodontic treatment and IDO. After treatment, appropriate occlusion, space closure in the maxillary arch, coincidence of the maxillary and facial midlines, and incorporation of the right maxillary first premolar into the arch were obtained. These results suggest that IDO is effective in treating cleft lip and palate patients with a wide alveolar cleft.

Introduction: Ameloglyphics is the study of enamel print patterns on the tooth surface. Enamel print patterns are unique to each individual as they differ on each tooth. The similarity of tooth prints on buccal and lingual surfaces remains questionable as no research has been conducted thus far. The premolar was chosen in this experiment due to its low risk of damage because it is protected by cheek and rarely used compared to other teeth. Thus, the results obtained will be more precise and have higher accuracy than using other teeth. This research was aimed to investigate the differences between enamel print patterns on buccal and lingual surfaces of maxillary right first premolar. Methods: An analytic study was conducted by observing and analysing a total of 34 teeth samples using the purposive sampling method. The middle third of the buccal and lingual tooth surfaces was captured directly after magnified with a stereomicroscope. Photomicrographs of samples were then analysed using SourceAFIS biometric software. This software will process the image and shows patterns of enamel print. Afterwards, the enamel print patterns were observed and classified according to Manjunath Classification. Results: The results suggested that all 34 samples show a similarity of enamel print patterns on both the buccal and lingual surfaces. The interpretations of photomicrographs were statistically analysed using the Statistical Package of Social Science (SPSS) software. The similarity may be due to the same placement of developing tooth bud, temperature, environmental factor, genetics, pressure and nutrition to the ameloblasts cells in a tooth. Conclusion: Both buccal and lingual in the samples show high similarity due to the very high frequencies of similar sub-patterns occur on both surfaces. Tooth print can be used as a valuable tool in forensic science for personal identification with good prospects in the field of forensic dentistry.

Introduction: Surgical lasers have been used in periodontal therapy. The anti-pain mechanism of low level laser is not yet clear however, numerous studies have pointed out the physiological changes from light interference with various cells as the cause. Low-level laser can also modify the inflammatory process in a dose-related mechanism; and thus, it can reduce the inflammatory pain.2 Methodology: A sample of 10 systemically healthy subjects aged 30-60 years diagnosed with chronic periodontitis having a probing pocket depth ?5mm and clinical attachment loss ?4mm bilaterally in the region of the maxillary first premolar, second premolar and first molar were recruited from the out-patient, Department of Periodontics, A.B.Shetty Memorial Institute of Dental Sciences. The subjects were blinded as to which surgical site received the laser therapy following conventional periodontal flap surgery (Test Group). The subjects were recalled one week after scaling and root planing for the periodontal flap surgery. At the baseline visit, the contralateral surgical sites were randomly assigned to the control group or the test groups using a coin-flip. In the test group, following the removal of soft deposits through scaling and root planing, the laser probe of 0.8W CW diode was used in a light contact, sweeping mode to cover the entire inner surface of the flap. Ablation was carried out from base of the flap to its coronal portion. Results-Median pain score did not differ significantly between the test and the control at 0 day, 1day , 2day and 5 day (P>0.05) ,day7 (P=0.087). Friedman test showed overall there was significant difference in pain score from o day to day7test. Pain score differs significantly from day 0 to day7 (P0.05) within test group. Conclusion-Lasers currently have a variety of uses in dentistry, although low-level lasers have been found beneficial in reducing the pain response after periodontal surgery in present study, but studies with larger sample are required to see significant association.

Purpose To evaluate the tightening torque maintenance with zirconia, lithium disilicate, and polyetheretherketone (PEEK) hybrid-abutment-crowns after thermal aging, in addition to assess the fracture resistance of hybrid-abutment-crowns fabricated with different materials. Materials and methods Thirty implants were restored with identical hybrid-abutment-crowns, resembling the maxillary first premolar, fabricated from zirconia (Zr), lithium disilicate (L2), or ceramic-reinforced PEEK (PE). The three groups (n = 10) were constructed utilizing a Ti-base. After bonding, each restoration was secured in its respective implant with a torque of 25 Ncm. All restorations were subjected to thermal aging for 7000 cycles. The loosening torque was assessed utilizing the digital torque meter. Each restoration was subjected to fracture testing and the mode of failure was determined. Results Zr group displayed the highest mean torque loss value (2.70 ± 0.59 Ncm) with the mean loosening torque value of 22.38 ± 0.68 Ncm. PE group displayed the lowest mean torque loss (2.55 ± 0.50 Ncm) with mean loosening torque value of 22.61 ± 0.59 Ncm. There was no significant difference between study groups regarding loosening torque (p = 0.68), torque loss (p = 0.80), and percentage of torque loss (p = 0.79). There was significant difference regarding the mean fracture load value between Zr and PE groups. However, there was no significant difference (p = 0.05) regarding mean fracture load value between L2 and PE groups. Conclusion The hybrid-abutment-crown material does not affect the torque maintenance after thermal aging. Based on fracture load, zirconia hybrid-abutment-crown can be used, while lithium disilicate and PEEK hybrid-abutment-crowns may cautiously serve in premolar region.