Search

To assess the efficiency of AI methods in finding radiographic features in Endodontic treatment considerations. This review was based on the PRISMA guidelines and QUADAS 2 tool. A systematic search was performed of the literature on cases with endodontic treatments, comparing AI algorithms (test) versus conventional image assessments (control) for finding radiographic features. The search was conducted in PubMed, Scopus, Google Scholar and the Cochrane library. Inclusion criteria were studies on the use of AI and machine learning in endodontic treatments using dental X-rays. The initial search retrieved 1131 papers, from which 24 were included. High heterogeneity of the materials left out a meta-analysis. The reported subcategories were periapical lesion, vertical root fractures, predicting root/canal morphology, locating minor apical foramen, tooth segmentation and endodontic retreatment prediction. Radiographic features assessed were mostly periapical lesions. The studies mostly considered the decision of 1–3 experts as the reference for training their models. Almost half of the included materials campared their trained neural network model with other methods. More than 58% of studies had some level of bias. AI-based models have shown effectiveness in finding radiographic features in different endodontic treatments. While the reported accuracy measurements seem promising, the papers mostly were biased methodologically. [ABSTRACT FROM AUTHOR]

To investigate the quality of root canal fillings and frequency of apical periodontitis (AP) in root canal filled teeth in a Swedish population. This study used data from a cross-sectional survey conducted in 2013. The root canal filling quality and periapical status were assessed in 491 root canal filled teeth in 196 individuals aged 20–70 years, randomly selected from the population of Jönköping, Sweden. All root canal filled teeth were examined with periapical radiographs. Three calibrated observers recorded length and density in root canal fillings as well as periapical status according to the Periapical Index. A root filling ending within 0.5–2 mm from the radiographic apex without lateral or apical voids was considered adequate. Data were analyzed in a generalized estimating equation (GEE) model with AP as dependent variable and gender, age, number of teeth, number of root filled teeth, tooth type, and root filling quality as independent variables. Teeth with technically inadequate root fillings were associated with AP in a simple GEE-analysis. In the multiple GEE-model, the association between technical quality and apical peridontitis was nonsignificant when controlling for tooth type and gender. The quality of root canal fillings is poor and the prevalence of AP in root canal filled teeth is high, particularly in molar teeth, in a Swedish population. [ABSTRACT FROM AUTHOR]

The purpose of the present study was to investigate the survival rate of root filled teeth in general dentistry in a Swedish county and to identify risk predictors with a significant influence on the survival rate. This is a retrospective 6-year follow-up study on 1642 recall patients with 1720 teeth root filled in general dentistry in the Public Dental Service in the county of Stockholm, Sweden. Background variables were collected from the database at baseline as potential predictors of tooth loss. The outcome variables were extraction during the 6-year follow-up period and the reason for the extraction. Stepwise Cox regression analysis was adopted in order to investigate the influence of the potential risk predictors on the risk for tooth extraction. Nine percent of the root filled teeth were lost after 6 years. The most frequent reason for tooth loss was fracture and/or cracks (58%). The survival rate of the root filled teeth increased significantly for younger patients, root filled teeth with metal crowns (96%) and high quality of the root filling (93%). The survival rate differed significantly between tooth groups with the lowest survival for molars (83%). Composite fillings were significantly associated with lower quality of the root fillings. Ninety-one percent of the root filled teeth survived after 6 years. The survival rate was significantly higher for teeth with root-fillings of high quality and metal crowns as well as for root filled teeth in younger patients. The lowest survival rate was found for molars. [ABSTRACT FROM AUTHOR]

This study aimed to compare the amounts of external root resorption (ERR) during different modalities of orthodontic treatment (OT) in root-filled teeth (RFT) and their contralateral teeth with vital pulp (VPT) in the same patient. The study sample consisted of 69 patients in two groups: 35 patients in the non-extraction group (18 female, 17 male; 18.16 ± 3.79 years), and 34 patients in the extraction group (19 female, 15 male; 17.72 ± 2.78 years). Digital panoramic radiographs of each patient taken before and after OT were used to measure the tooth length and root surface area. The amounts of ERR in RFT and contralateral VPT were evaluated pre- and post-OT in mandibular molars. The data were statistically analyzed with the paired t-test, independent t-test, and analysis of covariance (ANCOVA) (p <.05). A statistically significant difference was observed in both the orthodontic treatment groups when RFT and VPT were compared in terms of ERR (p <.05). A significant difference was observed between RFT and VPT in extraction treatments when the reduction in the root area between the two sides in the groups was compared (p <.05). RFT are more resistant to ERR than VPT. The ERR in RFT may not be a significant matter for the planning of OT. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to investigate the accuracy of endoscopic visualization to detect root canal anastomoses at the coronal half of the mesial root canals of mandibular molars using micro-computed tomographic (micro-CT) images as reference.Material and methods: Seventy-four mesial roots of mandibular first molars with (n = 47) or without (n = 27) intercanal anastomosis were selected based on the micro-CT scans of 269 mandibular first molars at a pixel size of 10 µm. The specimens were mounted on the mannequins and their root canals were evaluated using dental operating microscope (DOM) and endoscope. The endoscopic probe was inserted into the main mesial root canals and 2 blinded observers evaluated the presence of a divergence point of anastomosis (where the branching occurs) as 'present' or 'absent'. The scorings were compared with the three-dimensional reconstructed images of the specimens and recorded as 'correct' or 'incorrect' evaluation. Degree of agreement between evaluators was assessed with Kappa test and the accuracy of endoscopic visualization according to the presence and location of anastomosis was compared using Fisher exact tests with a significance threshold at 5%.Results: High inter-examiner reliability was reported (0.91). None of the divergence points were identified using DOM whereas 11 divergence points were detected using endoscope, corresponding the 23.4% of the intercanal anastomoses. The endoscope also showed the absence of an intercanal anastomosis correctly in all of the specimens without an anastomosis. Detectability of a divergence point using endoscope was not affected by its location within the coronal half of root canal (p > .05).Conclusions: The endoscopes were able to visualize the divergence points of 23.4% of the intercanal anastomoses located at the coronal halves of root canals. [ABSTRACT FROM AUTHOR]

Objective: The aim of this study was to compare apical debris extrusion when neodymium-doped yttrium aluminium garnet (Nd:YAG) lasers, erbium-doped yttrium aluminium garnet (Er:YAG) or photon-induced photoacoustic streaming (PIPS) are used for irrigation activation.Materials and methods: A total of 60 extracted human mandibular premolar teeth have similar dimensions were included and the samples were split into four groups according to the irrigation technique (n = 15): conventional needle irrigation, PIPS, Er:YAG and Nd:YAG. ProTaper Universal system up to F4 was used for root canal instrumentation. Bidistilled water was used as an irrigation solution during instrumentation and irrigation activation. Apically extruded debris was collected into preweighed Eppendorf tubes during instrumentation and irrigation activation procedures. The tubes were then kept in an incubator at 70 °C for 5 days. The initial weight of the tube was subtracted from the final weight and the result was recorded as the weight of dry extruded debris. The data were evaluated statistically using a one-way ANOVA test followed by least significant difference post hoc test (p < .05).Results: Conventional needle irrigation caused significantly less debris extrusion than laser-assisted irrigation activation groups (p < .05). Laser-assisted irrigation activation groups caused statistically similar debris extrusion (p > .05).Conclusion: Laser-assisted irrigation activation techniques caused more debris extrusion when compared to conventional needle irrigation. [ABSTRACT FROM AUTHOR]

Objective: In this study, the three-dimensional (3D) modification of root canal curvature was measured, after the application of Reciproc instrumentation technique, by using cone beam computed tomography (CBCT) imaging and a special algorithm developed for the 3D measurement of the curvature of the root canal.Materials and Methods: Thirty extracted upper molars were selected. Digital radiographs for each tooth were taken. Root curvature was measured by using Schneider method and they were divided into three groups, each one consisting of 10 roots, according to their curvature: Group 1 (0°-20°), Group 2 (21°-40°), Group 3 (41°-60°). CBCT imaging was applied to each tooth before and after its instrumentation, and the data were examined by using a specially developed CBCT image analysis algorithm.Results: The instrumentation with Reciproc led to a decrease of the curvature by 30.23% (on average) in all groups.Conclusions: The proposed methodology proved to be able to measure the curvature of the root canal and its 3D modification after the instrumentation. [ABSTRACT FROM AUTHOR]

Background: Recent advancements in clinical dentistry have increased the possibilities of surgical procedures in the mental region. A detailed knowledge of mental foramen (MF) morphometry is significant to preserve integrity of the mental nerve trunk in surgical interventions such as orthognathic surgery, implant placement and anaesthetic block.Objective: The aim of this study was to determine the most accurate position of the mental foramen by using new assessment approach in a sample of dental patients presenting to the specialist dental clinic, College of Dentistry, Al Jouf University, Saudi Arabia.Study Design: A retrospective study was performed using cone beam computed tomography (CBCT) of 600 patients (40.1 ± 11.78 years old). Following inclusion and exclusion criteria, 395 CBCT were finally obtained and analyzed for the most accurate position of the mental foramen (MF) by OnDemand 3D software (Seoul, Korea). Prevalence of shape of MF and accessory MF were also assessed. Pearson chi-square test was employed to test significant differences between genders and races.Results: The most common horizontal and vertical position of the mental foramen was in line with the long axis of 2nd premolar (41.3%) and below the root apex level (93.2%), respectively. The most common shape of MF was round type (72.66%). The prevalence of accessory 2MF and 3MF was 2.28% and 0.25%, respectively.Conclusion: New information about MF presented in this article can help anatomists, prosthodontists, orthodontists, surgeons, forensic odontologists and paleoanthropologists to predict the position of the MF and perform safer surgeries. [ABSTRACT FROM AUTHOR]

Objective: In the last few years there have been attempts to revascularize mature necrotic teeth instead of performing a standard root canal treatment. Apical foramen enlargement (AFE) would be necessary for regenerative treatments of mature teeth. In the literature, AFE has been made through apicoectomy and instrumentation. However, no standardized methods have been described yet, which may affect the success of the therapy. Our aim was to describe the effectiveness and damage to dental structures of five methods for AFE.Methods: Two hundred and ten human teeth were assigned to one control group (n = 10) and four treatment groups (n = 50 each): instrumentation was up to file #80 0.5 mm coronal to the apex (I), at apex level (II), 0.5 mm beyond the apex (III) and apicoectomy at 2 and 4 mm from the apex (IV). The apical foramen diameter was measured before and after treatment. The formation of clinically visible fractures (CVF) and microcracks was analysed clinically and with ESEM, respectively. Thirty-two in situ sheep's teeth were also instrumented, to compare damage in in situ and ex vivo teeth.Results: The foramen diameter was augmented by 0.15, 0.47, 0.54 0.06 and 0.32 mm in human teeth of groups I, II, III, apicoectomy at 2 and 4 mm, respectively. CVF were more frequent as the working length was augmented. No statistical differences were found for microcrack formation. In situ teeth showed significantly less damage.Conclusions: Instrumentation at apex level seems to be the most effective and least harmful technique for AFE, while apicoectomy is not a useful method. [ABSTRACT FROM AUTHOR]

Objective: The results in human sex chromosome aneuploidies had shown that the extra Y chromosome increases permanent and deciduous tooth crown sizes in the mesiodistal and labiolingual directions. The hypothesis of the study was that the additional Y chromosome increases the permanent tooth crown growth in a vertical dimension. We also aimed to observe possible sex difference in the permanent tooth crown height.Material and Methods: Data on 15 47,XYY males or males with an extra Y chromosome, nine male relatives (five brothers and four fathers) and 45 male and 48 female population controls had been gathered previously for Professor Lassi Alvesalo's KVANTTI Research Project. The measurements from panoramic radiographs were performed of all the applicable teeth, except the third molars on both sides of the jaws with a sliding digital calliper.Results: All the mean tooth crown heights in the 47,XYY males were larger than in the male population controls and the differences were statistically significant in six teeth in the maxilla and 10 teeth in the mandible. Apart from few teeth, the crown heights in the 47,XYY males were larger than in their male relatives, but the difference between these groups was significant only in one tooth. The differences between sexes were statistically significant in eight teeth in the maxilla.Conclusions: Based on previous investigations and this work, it is evident that the impact of the extra Y chromosome during tooth crown development is holistic, increasing permanent tooth sizes in three dimensions in a balanced manner. [ABSTRACT FROM AUTHOR]

Objective: The objective of this study is to evaluate the performance of four electronic root canal length measurement devices (ERCLMDs) [Root ZX, Raypex 6, ProPex II, and VDW Gold with ERCLMD] in wet and dry root canals with different major foramen diameters, in association with three file positions within the final 1 mm of canals.Materials and Methods: Fifty roots were divided into five groups that were instrumented apically to the terminus diameter using K-files 15, 20, 30, 40, and 60. ERCLMD measurements were made when the file tip was at major foramen, 0.5 mm and 1.0 mm short of the foramen, when the apex touched to the surface of saline or was immersed 3 mm into saline, and when the canal was dry or was irrigated with saline. The differences between the electronic lengths and the actual lengths were calculated. The data were analyzed using the three-, two-, and one-way ANOVA and the LSD test (p < .05).Results: Overall, the four ERCLMDs demonstrated 12.8% unstable and beyond the foramen measurements (11.3%). About 85% of the beyond the foramen measurements had foramen diameters 0.40 and 0.60. ERCLMD comparisons related to the file positions in the foramen diameters showed significant differences between ERCLMDs in each foramen diameter (p < .05).Conclusions: All ERCLMDs provided highly accurate measurements within the final 1 mm of the foramen. Wet or dry canals and apex conditions did not adversely affect the accuracy of the ERCLMDs' readings. ProPex II located the file positions in the teeth with different foramen diameters more accurately than the other ERCLMDs. [ABSTRACT FROM AUTHOR]

Objectives: To evaluate the effect of maleic acid (MA) on the cleaning efficacy and mechanical properties of root canal dentine with respect to different time exposure.Materials and Methods: One hundred and eighty single-canal premolars were instrumented with rotary-files and then randomly assigned to test groups receiving 7% MA for 30 s, 45 s, 1 min, or 3 min or to control groups treated with 0.9% saline or 17% ethylenediaminetetraacetic acid for 45 s. The micro-hardness, nano-hardness and elastic modules were measured before and after treatment, while the amount of smear and erosion in the coronal, middle and apical thirds in root canal were evaluated by scanning electron microscopy, finally, the fracture strength was assessed by vertical root fracture testing.Results: The efficacy of smear layer removal increased with increasing MA application time. The largest effect was observed at 45 s, even in the apical third, whereas the treatment for 1 min resulted in irreversible erosion of the dentine surface. The micro-hardness and nano-indentation testing confirmed that the micro- and nano-scale mechanical properties were significantly decreased after MA application for 1 min. Furthermore, the specimens treated with MA for 3 min presented the lowest fracture resistance among all groups. In contrast, the 45 s treatment appeared to increase the fracture resistance of the tooth.Conclusions: The cleaning efficacy and mechanical properties of root canal dentine varied with MA exposure time. The application of MA for 45 s was found to be the most promising for clinical use. [ABSTRACT FROM AUTHOR]

Objectives: Posterior bite-blocks are resin-based structures elevating the occlusion and creating intrusive force on the posterior teeth. Bite-blocks were applied to the molars of growing rats and a hard and soft diet was used to create altered functional masticatory forces. The aim of the present investigation was to study the effect of this appliance on the periodontal ligament space and alveolar bone thickness when combined with altered masticatory forces. Material and Methods: Fifty-two four-week-old rats were divided into two groups, hard and soft diet. Two weeks later, half of them received a bite-block appliance, creating four groups: control hard (CH), control soft (CS), bite-block hard (BH) and bite-block soft (BS). All were sacrificed at age of 10 weeks. Their heads were scanned by micro-CT and periodontal ligament space (PDL) width, cross-sectional alveolar socket surface and alveolar bone thickness were measured. Analysis of variance (ANOVA) was used to compare the groups. Results: The PDL was 9.2% thinner in the CS group (p < 0.001) and 20.7% in the bite-block groups (p  < 0.001) compared to the CH group. Within each of the four groups, the mesiodistal PDL space was larger than the palatobuccal. The alveolar bone was thinner by 5.8% (p = 0.018) in the CS group, 10.7% in the BH group (p < 0.001) and 16.7% in the BS group (p < 0.001) compared to the CH group. Conclusions: Young rats wearing posterior bite-blocks have narrower PDL space and thinner alveolar bone compared to controls. When fed a soft diet, the alveolar bone is even thinner but the PDL showed no difference. [ABSTRACT FROM AUTHOR]

Objective: Knowledge of primary tooth morphology is essential for clinical dentistry, especially for root canal treatment and dental traumatology. However, this has not been well documented to date with a large sample. This study was carried out to investigate the variation in number and morphology of the root canals of the primary molars, to study the applicability of cone beam computerized tomography (CBCT) in assessing the same and to provide a comprehensive review of the literature.Materials and Methods: A total of 343 primary molars, without any root resorption, were divided into four main groups including the maxillary first molars, maxillary second molars, mandibular first molars and mandibular second molars. All of them were analysed in CBCT images in the axial, sagittal and coronal planes. Various parameters such as the number of roots, number of canals, the root canal type, diameter of root and root canal and root canal curvature were studied.Results: Primary molars in all four groups showed variability in the number of roots and root canals. As far as length of the roots was concerned, the palatal root of the maxillary molar was found to be longest, while the distobuccal root was shortest. In mandibular molars, the mesial root was longer than the distal root. The length of distobuccal root canal of the maxillary molars and the distolingual canal of the mandibular molars was found to be shortest. The number of roots and root canals varied from two to four and three to four, respectively. The maxillary molars exhibited more one-canal than two-canal roots.Conclusion: The present study provides comprehensive information to the existing literature concerning the variation in root canal morphology of the maxillary and mandibular primary molar teeth. These data may help clinicians in the root canal treatment of these teeth. [ABSTRACT FROM AUTHOR]

Objective: The objective of the present study was to carry out a systematic review to analyse the effectiveness of pulp revascularization in the root formation of necrotic immature permanent teeth, as well as the level of scientific evidence regarding this theme.Materials and Methods: The methodology was based on searching electronic databases such as Web of Science, Pubmed, BVS (Medline, Scielo, Lilacs and BBO), Scopus and Cochrane, including manual searches for the references listed in the studies found. The terms used for the literature search were pulp revascularization and endodontics.Results: Initially, 277 articles were identified from the electronic databases; 17 studies remained after analysis and exclusion of duplicates; exclusion criteria also eliminated six articles; 11 remained for evaluation.Conclusions: Although the results found in the present systematic review are relevant, the scientific evidence should be interpreted with caution as the articles report different methods and evaluation parameters. Despite the capacity of the pulp revascularization technique to stimulate the development of the apical closure and thickening of radicular dentin, several aspects still remain unknown, like the key factors of this repair, the type of tissue formed and the long-term prognosis. [ABSTRACT FROM AUTHOR]

Objective. To study the association between type of restoration and apical periodontitis (AP) in root filled teeth. Materials and methods. The present study used data from surveys conducted in 1983, 1993 and 2003. In 1983, 130 randomly selected subjects aged 3-80 years in the city of Jönköping, Sweden, were invited for a clinical and radiological examination. The study was repeated in 1993 and 2003. New participants were, thus, recruited with the same sampling criteria and sample size in the same geographical area in 1993 and 2003, respectively. In the present study, only dentate individuals aged 20-70 years with ≥1 root filled tooth were included, yielding a sample of 788 subjects with 2634 root filled teeth. Apical periodontitis on the tooth level was the dependent variable. Periapical status was assessed according to Periapical Index (PAI). Independent variables were root filling quality, recurrent caries, type of restoration, number of teeth with apical periodontitis, age and gender. Root fillings appearing homogenous and ending within 2 mm from radiographic apex were regarded as adequate, otherwise inadequate. All radiographs were re-studied by one observer regarding periapical status and root filling quality. Risk was analyzed by means of a GEE model. Results. Type of restoration, root filling quality, number of teeth with apical periodontitis within the individual and age were found to be predictors of AP in root filled teeth. Presence of recurrent caries and gender were not found to be associated with AP. Conclusions. According to the present study, root filling quality and type of restoration may be predictive of AP in root filled teeth. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to evaluate the effect of residual calcium hydroxide [Ca(OH)2] on the accuracy of an electronic apex locator (EAL). Materials and methods. Working lengths (WLs) of 56 extracted maxillary incisors were determined initially by two different methods. The first method used the 'APEX' reading of the EAL as a reference point, 0.5 mm was subtracted and recorded as WL0. The second method used the '0.5' reading and the score was recorded as WL0.5 without subtraction. The roots were prepared to WL0 and divided randomly into three experimental groups ( n = 16) (1 mm in group A, 2 mm in group B and 4 mm in group C) and a control ( n = 8). Specimens in all experimental groups were filled with Ca(OH)2 paste. Following its removal, WLs were re-determined with the same methods. Results. In group C, pre/post WLs were significantly different ( p < 0.05). No significant difference was observed between the other experimental groups and the control group. Conclusion. Accuracy of EAL decreased proportionally with the amount of paste remaining at the ±0.5-mm tolerance level. Ca(OH)2 paste remnants may cause incorrect EAL readings. [ABSTRACT FROM AUTHOR]

Objective. Electronic apical foramen locators are now widely used to determine working length. This study was designed to determine whether tooth length influenced the accuracy of the Root ZX device. Materials and methods. Forty extracted maxillary canine teeth with a length range of 27-29 mm were selected. Access cavities were prepared and coronal flaring of canals performed. The teeth were mounted in self-polymerizing acrylic resin to facilitate horizontal sectioning except for the apical 3-4-mm portion of the root and embedded in alginate as the electronic medium. Electronic measurements were taken at the major foramen, 'zero' reading using the Root ZX and compared with the actual root canal length. The teeth were sectioned 3 mm from the coronal reference point to create a second group with shorter length; these reductions in the length continued six times in all to create seven groups of 40 specimens each. The actual and electronic lengths of specimens in each group were measured. Data were analyzed by Pearson's correlation coefficient. Results. Identical measurements between the actual and electronic root canal length from the longest to the shortest groups were 12.5%, 10.0%, 20.0%, 27.5%, 37.5%, 35.0% and 45.0%, respectively. There was a mild negative correlation between the precise measurements of the Root ZX and root canal lengths in the seven groups ( r = −0.964, p < 0.001). Conclusion. Under the conditions of the study, the Root ZX device was more accurate in shorter teeth compared to longer ones. [ABSTRACT FROM AUTHOR]

Objective. To evaluate root canal morphology of permanent mandibular incisor teeth in a Chinese population using cone-beam computed tomography (CBCT). Materials and methods. CBCT images of Chinese patients were collected and 1553 permanent mandibular incisors in the images were included. The following observations on the included teeth were to determine the number of roots, root morphology and canal configuration. The root canal configurations were classified. The effect of gender on the incidence of the second canal was investigated. Results. Of permanent mandibular incisors, 86.8% had a single root with single canal. Mandibular lateral incisors (17.5%) had a higher incidence of a second canal compared with mandibular central incisors (8.9%) ( p = 0.000). A slightly higher percentage of incidence of a second canal was found in males (14.6%) than in females (11.9%) ( p = 0.129). Conclusions. Permanent mandibular incisors with two canals had a relatively low incidence in this Chinese population. The incidence of a second canal did not differ between males and females. CBCT is a valuable aid during root canal treatment. [ABSTRACT FROM AUTHOR]

Introduction. The aim of this study is to compare the root canal transportation with the PathFile-ProTaper recommended protocol, PathFile-ProTaper modified protocol and stainless steel K-flexofiles. Methods. Forty-five ISO 15, 0.02 taper S-shaped Endo Training Blocks were divided randomly into three groups of 15 each and prepared as follows: PathFile-Protaper recommended protocol, Pathfile-Protaper modified protocol and manual preparation with K-Flexofiles. The amount of transportation was assessed by scanning the blocks before and after preparation and superimposing the images. The cutting effects of the instruments from the inner and outer aspects of the root canals were measured and statistically analyzed with the One-way Anova test and Tukey HSD test. Results. Manual preparation caused significantly more transportation than both PathFile-Protaper systems. There was no significant difference regarding transportation between the two Pathfile-Protaper protocols. Conclusion. The modified Pathfile-Protaper protocol transported the canal similar to the recommended Pathfile-Protaper protocol. It may be suggested that, while working safety remains unchanged, the shaping procedure and consequently working time can be shortened with fewer instruments. The results of this study can help clinicians to reduce the preparation time with the PathFile-ProTaper rotary system while the preparation quality remains the same. [ABSTRACT FROM AUTHOR]

Objectives: This study investigated the long-term survival and the prognostic factors of endodontic treatments performed in a dental teaching hospital. The aim was to calculate the probabilities of success or failure according to the follow-up extent and to assess the time allowed for a complete periapical healing. Materials and methods. A cohort of 185 teeth were re-examined 1-4 years after treatment. The outcome was assessed on the basis of radiographic and clinical criteria as success, uncertain or failure. A survival analysis using the Cox model was used (i) to explore tooth survival and periapical healing over the time and (ii) to highlight the predictive factors of treatment outcome. Results. After 2 years, the appearance of an apical periodontitis remained lower than 3.5%, whereas only 22.8% of periapical healed cases were notified. The prognosis factors are: (i) for teeth with initial healthy periapical conditions, coronal leakage ( p = 0.002) with the higher risk of failure (RR = 19.77), absence of correspondence filling length/shaping = 0.026), type of teeth ( p = 0.041) and (ii) for teeth with apical periodontitis, number of root canals ( p = 0.000,91), correspondence filling length/shaping length ( p = 0.017) and over-filling ( p = 0.09). New periapical lesions or tooth loss were recorded after 2 years. Half of the successful cases of periapical healing were observed during the follow-up from 2-4 years. Conclusions. This longitudinal study shows that coronal leakage is responsible for late failure and that periapical healing is long to achieve. Therefore, endodontic treatments may require a follow-up of over 2 years. [ABSTRACT FROM AUTHOR]

Objective: To determine the number, shape and diameter of minor apical foramina, the distance between apical foramina and anatomical apex and the frequency of accessory foramina in a Turkish population. Materials and methods: Eight hundred permanent maxillary and mandibular teeth were collected. The roots were stained with methylene blue and the apices were examined with a stereomicroscope (×40) and transferred to a computer to perform the measurements using Adobe Photoshop software. Results: The incidence of one apical foramen was highest in distobuccal roots of the maxillary first molars and was lowest in the maxillary first premolars with single roots. The distance of deviation in all the teeth was between 0.271-0.519 mm. The frequency of accessory foramina was between 30-70% for the various tooth types. Conclusions: The results of this in vitro study indicate that the morphology of apical foramina in this Turkish population may present highly complex anatomical variations. [ABSTRACT FROM AUTHOR]

Objective. To evaluate the sealing ability and bond strength of AH Plus sealer associated with the hybridization protocol of radicular dentin with Scotchbond Multi Purpose (SB). Materials and methods. Ninety palatal roots of maxillary molars were selected and divided into three groups ( n = 30) according to filling protocol (G1, AH Plus/Resilon; G2, SB/AH Plus/Resilon; and G3, AH Plus/Gutta-Percha). In groups in which AH Plus + resin cones were used, dentin was hybridized before applying sealing material. For the bond strength test, 60 roots of bovine teeth were selected. Six holes were made in each root, two in the cervical, middle and apical third of the root. The roles were filled with AH Plus sealer with or without an adhesive system and submitted to push out test and the fracture mode was examined using a stereomicroscope (×32). Results. Statistical analysis showed that ScotchBond Multi Purpose (SB) + Resilon cone + AH Plus group promoted higher sealing ability than the gutta-percha + AH Plus group ( p < 0.05). Bond strength was lower with SB application than without it ( p < 0.05). A reverse correlation was found between bond strength and sealing ability. The fracture mode methodology revealed 22.77% of adhesive, 11.67% of cohesive and 65.55% of mixture fractures for SBMP/AH Plus protocol, whereas the AH Plus protocol indicated 86.11% of cohesive and 13.89% of mixed fractures. Conclusion. It was concluded that the use of the adhesive system Scotchbond Multi Purpose improved coronal sealing ability of AH Plus, but bond strength of sealer was reduced when adhesive was applied. [ABSTRACT FROM AUTHOR]

Objective. To compare the smear layer removal efficacy and erosive effects of different irrigation protocols under clinical and laboratory conditions. Materials and methods. Mandibular third molars ( n = 32) of 30-45 year-old patients were instrumented with rotary files and were randomly assigned to one of the following groups for final irrigation: (1) 5.25% NaOCl; (2) 17% EDTA; and (3) BioPure MTAD. Thereafter, the teeth were immediately extracted and processed for micromorphological investigation. In vitro specimen pairs were prepared by repeating the clinical experiments on freshly-extracted mandibular third molars. To compare open and closed systems, laboratory experiments were repeated on 32 additional teeth with enlarged apical foramen. The cleanliness of the root canals and the extent of erosion were assessed by environmental scanning electron microscopy. Results. Specimens prepared under clinical and laboratory conditions had similar cleanliness and erosion scores ( p > 0.05). Under both conditions, the tested solutions were more effective in removing the smear layer in the coronal and middle regions than in the apical one. Comparison of closed and open systems showed similar levels of cleanliness and erosion in all regions ( p > 0.05), with the exception of 17% EDTA showing significantly higher levels of cleanliness and erosion in the apical third of open-end specimens. Conclusions. Based on clinical correlates of in vitro root canal cleanliness and erosion, laboratory testing of root canal irrigants on extracted teeth with closed apices can serve as a reliable method to simulate the clinical condition. EDTA was the most effective final irrigation solution in removing the smear layer at the expense of yielding the greatest erosive effect. [ABSTRACT FROM AUTHOR]

Objective. The aim of this study was to evaluate the effect of different core materials and post length on the fracture strength of different posts (CAD/CAM zirconia post (ZR post)) and an individually formed glass fiber reinforced composite post (FRC post). Materials and methods. One hundred maxillary central incisors received endodontic treatment and were divided into two groups according to the post length: (1) 10 mm in length and (2) 15 mm in length ( n = 50/per group). Then the specimens were randomly assigned into five sub-groups ( n = 10/per group) as follows: One-piece milled zirconia post and core (group Zr), zirconia post with resin core (Biscore, Bisco) (group Zr/R), zirconia post with resin composite core (Admira, Voco) (group Zr/RC), FRC post with resin core (group F/R) and FRC post with resin composite core (group F/RC). The posts were cemented with a self-adhesive luting agent according to the manufacturer's instructions by using endo tips and light-cured for 40 s using a halogen light curing unit. Metal crowns were made for each specimen, cemented and loaded to failure. Fracture loads (N) and modes of failure were recorded. The data were analyzed using three-way analysis of variance (ANOVA) followed by Tukey's post-hoc test ( p < 0.001). Results. Fracture strength of roots was significantly affected by the type of post material ( p < 0.05) and post length ( p < 0.05), but not by the type of core materials used ( p = 0.078). Conclusion. Longer zirconia posts with zirconia- or resin-based cores can be recommended as an alternative to FRC posts with resin-based cores. The fracture patterns observed in teeth restored with fiber posts were more favorable than teeth restored with zirconia posts. Clinical significance. A higher restoring success rate can be achieved by fiber posts rather than zirconia posts, since the failure mode for these posts would be restorable. Additionally, post length is a more critical factor in teeth restored with one-piece milled zirconia posts than in those restored with fiber posts. [ABSTRACT FROM AUTHOR]

Objective. Root resorption, impaired tooth eruption and early tooth loss have been described in relation to diseases that involve defects in the RANK-RANKL-OPG-expression. The aim of the present immunhistochemical study was to localize and compare the reactions for RANK and membrane-bound RANKL along root surfaces and in the periodontal membrane in close proximity to the root surface of human primary and permanent teeth. Materials and methods. The material comprised extracted human teeth (11 primary teeth and six permanent teeth) from 10 different patients. Paraffin sections were prepared of each tooth and sections of each tooth were immunohistochemically stained with antibodies specific for membrane-bound RANKL and RANK. Results. The root surface and the periodontal membrane in close proximity to the root surface did not show immunoreactivity for RANKL. RANKL was only located in odontoblasts and in cells along denticles in one primary tooth. RANK was located in mononuclear cells in the pulp and in multinucleated odontoclasts along resorbed root surfaces and along resorbed dentin surfaces in the pulp in primary teeth and one permanent tooth. Conclusions. This study demonstrated RANK positivity in resorption areas in primary and permanent teeth. RANKL was positive in the pulp of one primary tooth. RANK expression in odontoclasts and RANKL expression in the pulp may indicate that RANK/RANKL play a role during resorption. [ABSTRACT FROM AUTHOR]

Objective. The aim of the study was to test the hypothesis that root-filled teeth are at a higher caries risk than non-root-filled teeth. Materials and methods. Two sub-samples from epidemiologically obtained data collected in 1983, 1993 and 2003 in the city of Jönköping, Sweden, were analysed. All the participants were examined clinically and radiographically and the type of filling and the presence or absence of caries were recorded. Sub-sample 1 comprised 832 individuals (9202 teeth) aged 20-70 years with at least eight premolars/molars. In sub-sample 2, 163 subjects (577 teeth) with only one or two decayed tooth surfaces and at least one tooth with full crown coverage were analysed. Results . Logistic regression analysis found that root-filled teeth were predictive of recurrent caries when controlling for the type of restoration in sub-sample 1 (OR == 1.68; 1.41-2.0; CI 95%) and sub-sample 2 (OR == 2.20; 1.07-4.52; CI 95%). Conclusion . In support of the suggested hypothesis, the data revealed a significant association between root-filled teeth and recurrent caries. [ABSTRACT FROM AUTHOR]

Objective. Recent studies revealed a highly innervated layer in close proximity to the root surface in the periodontal membrane of human teeth. Persistence of the epithelial cells of Malassez along root surfaces without resorption has also been demonstrated. It is hypothesized that resorption is connected to apoptosis of the epithelial cells of Malassez. The purpose of this study is to localize cells undergoing apoptosis in the periodontal membrane of human primary and permanent teeth. Materials and methods. Human primary and permanent teeth were examined immunohistochemically for apoptosis and epithelial cells of Malassez in the periodontal membrane. All teeth examined were extracted in connection with treatment. Results. Apoptosis was seen in close proximity to the root surface and within the epithelial cells of Malassez. This pattern of apoptotis is similar in the periodontal membrane in primary and permanent teeth. Conclusions. The inter-relationship between apoptotis and root resorption cannot be concluded from the present study. Apoptosis seen in close proximity to the root surface presumably corresponds to the highly innervated layer of the periodontal membrane. The function of this layer still needs to be elucidated. [ABSTRACT FROM AUTHOR]

Objective. Previous studies have demonstrated differential effects of the X and Y chromosomes on dental development. The expression of sexual dimorphism in terms of tooth size, shape, number and developmental timing has been explained especially by Y chromosome influence. The Y chromosome promotes enamel, crown and root dentin development. The X chromosome has an effect on enamel deposition. The aim of this research is to study the influence of the extra X chromosome on the development of permanent tooth root length. Material and methods. The study subjects (all of whom were from the Kvantti Dental Research Project) were seven 47,XXX females, five female relatives and 51 and 52 population control men and women, respectively. Measurements were made from panoramic radiographs on available permanent teeth by a digital calliper according to established procedures. Results. The results showed that the maxillary root lengths of the 47,XXX females were of the same magnitude as those in normal women, but the mandibular root lengths were longer in 47,XXX females than in normal men or women. Conclusions. Increased enamel thickness in the teeth of 47,XXX females is apparently caused by the active enamel gene in all X chromosomes having no increased influence on crown dentin formation. These results in 47,XXX females indicate an increase in root dentin development, at least in the mandible, which together with the data on crown formation reflects a continuous long-lasting effect of the X chromosome on dental development. [ABSTRACT FROM AUTHOR]

Objective. The purpose of this study was to establish reference values for maturity of permanent canines, premolars, and permanent 2nd molars in Danish children, and to focus on differences between the right and left sides, males and females, and the maxilla and mandible. Material and Methods. Panoramic radiographs from 106 males (8-14 years) and 137 females (7 years 2 months to 13 years 8 months) were analyzed, along with the maturity of the canines, premolars, and 2nd molars in each radiograph. Each tooth was categorized according to Haavikko's crown and root morphology. Inter-observer reliability was performed. For statistical analysis, Bowker's test was used for symmetry evaluation and comparison of maturity in the maxilla and mandible. The association between stage and age was presented by cumulative distributions. The Wilcoxon rank sum test was used for evaluating differences between genders. Results. Differences in maturity between the left and right sides were non-significant. A significant difference in dental maturity was observed between males and females, except for the maxillary 2nd premolar. Females matured earlier than males. The mandibular canines matured significantly earlier than the maxillary canines in females. No significant differences between the jaws were observed in the maturation of the premolars and 2nd molars. Conclusion. These reference values for dental maturity can be useful in orthodontic treatment planning and as a reference for odontological forensic age determination. [ABSTRACT FROM AUTHOR]

Objective. To investigate the effect of age on root resorption and distribution along different parts of the root during prolonged light force application. Material and methods. Orthodontic appliances were placed in two groups of 30 rats (one group 6 weeks old, the other 9-12 months old), with contralateral sides as controls. Groups of animals were killed at 1, 2, 4, 8, and 12 weeks. At the study site, incidence was counted as either 1 (with resorption) or 0 (without); severity was measured as the summed length of all resorption lacunae as a percentage of study total root length. Results. Young and adult rats had the same incidence of root resorption in the early phase (<4 weeks), and both increased in the late phase (4-12 weeks) to the same level. Severity of resorption increased with prolonged tooth movement only in adult rats. However, there was no age-related difference in either the early or the late phase. In both groups, the middle part of the root had the highest incidence of resorption; the most severe resorption occurred exclusively at this part. Conclusion. Orthodontic intervention even with light forces increased both the incidence and severity of root resorption, the more so in the middle part of the root. Adult rats had increased incidence and severity with prolonged tooth movement. [ABSTRACT FROM AUTHOR]

Objective. The aim of this retrospective cohort study was to assess the association between background factors and future endodontic treatment due to caries in young permanent teeth. Material and methods. The material comprised all 19-year-olds born in 1979 in a city in Sweden who had experienced endodontic treatment due to caries in permanent teeth (n=105) and a control group with no endodontic treatment. From dental records, the following independent variables were derived from age 7 to age 19: immigrant background, caries prevalence (DMFT values) at age 10, occurrence of dental anxiety, and missed or cancelled appointments before endodontic treatment. The outcome variable was presence or absence of endodontic treatment due to caries. Bivariate analysis and a multiple logistic regression model were used to analyse the data. Results. In the bivariate analyses, all independent variables except cancelled appointments were statistically significantly associated with future endodontic treatment. Of these, immigrant background did not remain as a statistically significant factor in the multiple regression model. The highest odds ratios were 4.3 for >2 DMFT at age 10 and 4.1 for >20% missed appointments. Conclusion. In the present sample, with a relatively high proportion of individuals with an immigrant background, >2 DMFT at age 10, many missed appointments and dental anxiety were all risk indicators for future endodontic treatment due to caries up to age 19. [ABSTRACT FROM AUTHOR]

The objectives of the present prospective longitudinal study were to establish the survival and success rates for premolars with partly developed roots transplanted according to a set protocol, and to analyze the effect of varying pre-surgery root development on final root length. Standardized periapical radiographs of 132 consecutively transplanted premolars were obtained at predetermined intervals over a 4-year follow-up period. Survival and success rates were calculated on the basis of presence of teeth and recording of defined radiological variables, respectively. Final root length was compared to normative metric data for root morphology. From the total sample, 54 patients with 68 transplanted premolars suitable for analysis of root growth relative to initial root length were identified, and divided into subsamples according to root length pre-transplantation. Survival rates were 100% after 1, 2, and 3 years, and 98.6% 4 years post-transplantation. The success rates were 92.9%, 92.8%, 89%, and 90.5% in subsamples collected 1, 2, 3, and 4 years after transplantation, respectively. The transplants obtained on average 78% of normative root length, and by dichotomizing the transplanted teeth in subsamples with 'short' and 'long' roots pre-surgery, similar final root lengths were observed even if 'short' roots had the greatest increase. Very early transplantation (roots < 7 mm), however, tended to result in short final root length. It is concluded that the success and survival rates were comparable to results obtained in similar studies. Initial root length was a significant predictor of root length increase. Transplanting teeth with short roots is to risk short final root length. [ABSTRACT FROM AUTHOR]

The aim of this study was to elucidate whether a premaxilla with a supernumerary tooth has additional dental abnormalities. The study does not include premaxillas with a mesiodens, only premaxillas with parasagittally located supernumerary teeth. Radiographs from eight children, followed from 1 year and 5 months to 11 years and 5 months in the municipal dental health service in Denmark, were analyzed. One patient was seen only once. Dental abnormalities recorded included: invaginations on permanent incisors, resorption of roots of incisors, curved roots of incisors, delayed eruption, and delayed formation of roots. The study shows that there are dental abnormalities within the premaxillary region where the supernumerary tooth is located. This indicates that, apart from the supernumerary tooth, a more widespread deviation from normal conditions including tooth malformation, arrested eruption, and root resorption occur within the premaxillary region. The most important outcome of this study is that in the region with a supernumerary tooth the adjacent incisor shows delayed eruption after surgical removal of the supernumerary tooth. The deviations in root morphology, including root resorption, are not limited to patients who have had orthodontic treatment, but patients who did not receive orthodontic treatment also revealed deviations in root morphology. Therefore the treatment outcome can be different from the expected outcome. [ABSTRACT FROM AUTHOR]

Short-root anomaly (SRA), occurring mostly in maxillary incisors, is defined as developmentally very short, blunt dental roots. The condition has a genetic background and is related to hypodontia. Earlier population studies have been based on schoolchildren with developing dentitions and have indicated prevalence figures between 1% and 10%. We studied a random sample of existing panoramic radiographs of 2000 university students for SRA. Roots as long as or shorter than the crowns in the incisors and visually evaluated as very short, blunt roots bilaterally in the posterior teeth were classified as SRA. The prevalence was 1.3%. According to anamnestic information, half the SRA patients had undergone orthodontic therapy, but pre-treatment radiographs were unavailable. In 70% of the SRA patients the short-rooted tooth pairs were upper incisors, but also involved were maxillary premolars, lateral incisors, and lower second premolars. Women were significantly more often affected. We discuss other factors known to cause short-rooted teeth and conclude that the population prevalence for genetic SRA in fully developed dentitions is close to our 1.3%. [ABSTRACT FROM AUTHOR]

Aluminum (Al) concentration was assessed in deciduous teeth in relation to sex, year of birth, tooth type, and the presence of caries and roots. Three hundred and twenty-three deciduous teeth from children born during the period 1952 93 in a county in southeast Sweden were sampled, and the Al content determined by graphite furnace atomic absorption spectrophotometry. The arithmetic mean of the Al concentration was 0.58 +/- 0.64 ppm dry weight (mean +/- standard deviation) and differed significantly between incisors (1.05 +/- 1.04 ppm) and canines (0.48 +/- 0.50 ppm) and between incisors and molars (0.53 +/- 0.55 ppm). A significant difference was found between teeth with and without caries. No significant differences were found between sexes. The Al concentration correlated significantly with tooth weight for incisors (r = -0.47) and canines (r = -0.45) but not for molars (r = 0.03). No significant change in Al concentration was found over time. Caries-free deciduous molars are suggested as the most useful teeth for biological monitoring of aluminum. [ABSTRACT FROM AUTHOR]

Two lingual root structures are occasionally found on human permanent maxillary molars. One of these is the normal lingual root, which is always present, the other is a supernumerary structure which can be located either mesiolingually (radix mesiolingualis (RML)) or distolingually (radix distolingualis (RDL)). The available literature refers only to the existence and location of RML and RDL Very small materials have, quite simply, hitherto precluded a more detailed description of these roots. The large collection of extracted teeth at the School of Dentistry in Copenhagen now includes a non-random subcollection of 145 permanent maxillary molars, the root complex of which contains 2 lingual root structures. Based on this material it was possible to undertake a modern, systematic analysis of the macromorphological variation of RMLs and RDLs. In this study, which was mainly non-metric, criteria for the identification of RML and RDL were established. The analysis also showed that the lingual supernumerary roots were only rarely found on the first molar, but with increasing frequency on the second and third molars. Both separate and non-separate RML and RDL were observed. In the material, degrees of separation greater than 0.9 were registered, degrees of divergence up to approximately 45 degrees, an apical bend of approximately 90 degrees, and extreme apical slenderness. Even though the supernumerary roots described here do not occur very often, knowing about them is nevertheless clinically relevant in for example endodontic and surgical contexts. [ABSTRACT FROM AUTHOR]

The School of Dentistry in Copenhagen possesses a collection of 96 human permanent maxillary molars (M sup) with a root complex, the macromorphology of which includes a facially located supernumerary root known as radix paramolaris (RP) and/or a distally located supernumerary root called radix distomolaris (RD). Systematic analysis of these teeth enabled the authors to establish precise criteria for the identification of RP and RD on M sup; 91.5% out of a total of 70 RP identified occurred on M3 sup, 7.2% on M2 sup, and 1.4% on M1 sup. The corresponding percentages for 29 RD identified were: 96.5% on M3 sup, 3.4% on M2 sup, and 0.0% on M1 sup; 50.0% of the 70 RP were separate in relation to the 2 facial root components and 31.5% non-separate; in 18.6% of the RP observed, it was impossible to establish whether or not they were separate. Corresponding frequencies for the 29 RD in relation to the distofacial and lingual root components were 41.3% separate and 37.9% non-separate; 20.7% of the roots could not be categorized. The following clinically relevant macromorphological variables regarding RP and RD were also observed: degree of separation in relation to the respective neighboring root components, degree of divergence in relation to the same macrostructures, apical bend, apical gracility, and pattern of fusion. [ABSTRACT FROM AUTHOR]