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To investigate the milling properties of different yttria-tetragonal zirconia polycrystalline (Y-TZP) block materials by applying a dental computer numerical control (CNC) milling center. Low temperature sintering zirconia block denoted by KMUZ (experimental) with two commercial zirconia blocks for T block made in Taiwan and a G block made in Germany were compared for the milling properties. Seventy-two specimens were milled using the same CNC milling center, and properties were evaluated by measuring the weight loss (g), milling time (s), margin integrity (%) and broken diameter (μm). The crystalline phases contents were identified by X-ray diffraction and the microstructures of the sintering specimens were observed by scanning electron microscopy and transmission electron microscopy. The mean milling time of G and KMUZ were significantly shorter than T (P

This study aimed to evaluate the tongue’s role in supporting maxillary denture retention (MDR), in providing additional stabilization for the mandibular denture, and the tongue’s relationship with the oral health-related well being in elderly complete denture patients. Four hundred elderly individuals, 263 males and 137 females, were enrolled in this study. All were older than 65 years, and wore complete dentures. Intraoral examinations were performed in accordance with the 10 criteria embedded in the Functional Assessment of Dentures (FAD). Participants also received personal interviews and completed the Oral Health Impact Profile-14 (OHIP-14) questionnaire. The associations between MDR (tongue support) with the mean OHIP-14 sum scores and FAD categories were analyzed using the t test or analysis of variance (ANOVA). Combinations of MDR (tongue support), MDR (resistance to vertical pull), and mandibular denture stability (anterior–posterior movement) were also assessed with the remaining FAD criteria and OHIP-14 domain scores. Individuals with adequate MDR (tongue support) were significantly associated with denture articulation, denture occlusion, MDR (resistance to vertical pull), maxillary denture stability (pronounced rocking), and mandibular denture stability (anterior–posterior movement). When individuals with adequate MDR (tongue support) were analyzed in conjunction with adequate MDR (resistance to vertical pull) and adequate mandibular denture stability (anterior–posterior movement), significant associations were observed with the mean OHIP-14 sum score and three individual OHIP-14 domains: functional limitation, physical pain, and physical disability (p ＜ 0.05). The mean OHIP-14 sum score was lower among individuals with both adequate MDR (tongue support) and inadequate MDR (resistance to vertical pull) than among participants with both inadequate MDR (tongue support) and inadequate MDR (resistance to vertical pull). MDR (tongue support) demonstrated significant differences from denture occlusion, denture articulation, MDR (resistance to vertical pull), maxillary denture stability (pronounced rocking), and mandibular denture stability (anterior–posterior movement). MDR (tongue support), in conjunction with both adequate MDR (resistance to vertical pull) and adequate mandibular stability (anterior–posterior movement), were significantly associated with the individuals’ oral health-related well being.

During surgical correction of facial deformities, accurate prediction of the resulting facial profile is important for the patient and the surgeon. The purpose of the present study was to investigate profile changes after surgical treatment of mandibular prognathism. Thirty patients (20 females and 10 males; ages 17–28 years) with mandibular prognathism underwent vertical ramus osteotomy. Preoperative and postoperative cephalograms were analyzed; landmarks were identified and compared. The mean horizontal setback of the pogonion (Pog) was 11.7mm. The setback ratios of labrale inferius (Li)/incision inferius (Ii), labiomental sulcus (Si)/point B, and soft tissue pogonion (PogS)/pogonion (Pog) were 0.98, 0.99, and 0.95, respectively. There were no sex-related changes in soft tissue. These findings indicate that changes in soft tissue closely correlate with the amount of mandibular setback in the horizontal direction. Such information might facilitate more accurate prediction of the outcome of orthognathic surgery.

doi: 10.1111/j.1741-2358.2012.00632.x Evaluation of a self-assessed screening test for masticatory ability of Taiwanese older adults Objectives: The aim of this study was to evaluate a screening test based on a food intake questionnaire to discriminate the masticatory ability of Taiwanese older adults with 20 and more natural teeth and at least 8 functional tooth units (FTUs) from the masticatory ability of those with fewer than 20 natural teeth and 8 FTUs. Materials and Methods: The subjects were 2244 patients (mean age, 60.4±10.0 years) recruited from 23 counties and cities in Taiwan. Information about their demographic data, dentition, and masticatory ability was collected. Masticatory ability was measured for 23 food groups comprising 35 common Taiwanese foods, and receiver operation characteristic curve analysis was performed. Results: The results showed that the final questionnaire included 14 food groups and a subject choosing ’difficult to eat‘ responses for 4 and more of these food groups had the same masticatory ability as individuals with fewer than 20 natural teeth and 8 FTUs. Conclusion: In conclusion, foods that are the most difficult to eat are not necessarily good discriminatory indicators. Hence, the 14-food group questionnaire can be considered the best screening test for masticatory ability of Taiwanese older adults in terms of the presence of 20 and more natural teeth and at least 8 FTUs.

doi: 10.1111/j.1741-2358.2011.00500.x Effects of denture maintenance on satisfaction levels of Taiwanese elderly using removable partial dentures: a pilot study Objective: The aim of this study was to evaluate the correlation between patient satisfaction with removable partial dentures and denture maintenance by patients, including regular application of denture adhesives and cleansers. Background: The success of removable partial dentures depends on patient satisfaction with dentures and their regular denture maintenance. Materials and methods: Demographic information, the Oral Impacts on Daily Performance (OIDP) indicator and details of denture maintenance (including the use of denture cleansers and adhesives) were collected from 193 (41.5% men and 58.5% women) participants by using questionnaires. A dentist performed oral examinations to evaluate denture function according to the OIDP items photographically and recorded the number of remaining teeth and Kennedy’s classification. Results: Most participants were satisfied with their removable partial dentures and tended to have higher satisfaction levels than the dentist’s estimation. Further, those using denture adhesives and cleansers had higher satisfaction levels than those not using such denture maintenance. Conclusions: Appropriate education regarding denture use is important because regular denture maintenance by patients affects their degree of satisfaction with dentures, as well as the dentist’s skill and the patient’s oral condition. Dentists could use this information to predict the potential success of dentures.

Statement of the Problem: Fabrication of normal crown contour to maintain gingival health is difficult in the absence of emergence angle data. Purpose: The aim of this study was to measure the geometric values of the emergence angles on the cementoenamel junction (CEJ) for natural maxillary anterior teeth. Material and Methods: This study collected 148 natural permanent maxillary anterior teeth (74 central incisors, 59 lateral incisors, and 15 canines) with intact cervixes for this study. The teeth were scanned with a three-dimensional (3D) scanner to construct 3D models. This study measured the emergence angles of the cervical CEJ on the zenith of labial, palatal, mesial, and distal, for each tooth. Results: Measurements made on 148 maxillary anterior teeth showed the emergence angle to be within a narrow range from 11.30° to 15.26°, irrespective of the tooth location. There were no statistically significant differences between any two groups (p > 0.05). Conclusions: On the basis of measurements taken from natural teeth, we conclude that the emergence angles of the CEJ in natural maxillary anterior teeth should be 15° from the root surface. CLINICAL SIGNIFICANCE The information presented in this article may be useful in helping to create dental restorations with optional emergence angles over the CEJ in natural maxillary anterior teeth. Prior to the treatment the dentist should consider not only the fit of the crown, but also the emergence angles and contours of the soft tissues surrounding the involved teeth. (J Esthet Restor Dent 23:362–370, 2011)

The gonial region is coincided with harmonious face and masticatory function. The aims of the present study were to assess changes in the gonial region in patients who had mandibular setback surgery by intraoral vertical ramus osteotomy (IVRO) and to investigate the contributing factors in relation to skeletal relapse.Twenty-one patients with mandibular prognathism were corrected by IVRO. Three cephalometric radiographs were collected from preoperative orthodontic treatment (T1), immediately after surgery (T2), and at 2-year postoperative follow-up (T3). Relapse was defined as forward movement of menton (Me) after the 2-year follow-up. Three angular (SN-Go angle, mandibular plane angle, and gonial angle) and 2 linear (horizontal-Me and vertical-Me) measurements were compared after immediate operation and at the 2-year follow-up. Spearman rank correlation and Student t tests were used for statistical analysis.The mean setback of the Me was 12.7 mm, and the mean relapse was 1.5 mm. The magnitude of setback was not significant for relapse. There were weak correlations between relapse and factors concerned with the gonial region (SN-Go angle, mandibular plane angle, and gonial angle).Surgical correction of mandibular prognathism using IVRO can lead to an increase in the angle changes of gonial region but not correlate to skeletal relapse in long-term follow-up.

Several reports have pointed out that endodontically treated teeth can lack strength, and that the teeth can be reinforced using posts. However, it has not been clear how to select posts that meet the needs of most clinical situations, particularly in terms of the post diameter, which has a major influence on the occurrence of root fracture. The purpose of this study was to analyze the stress distributions of posts of various diameters during masticatory loads using a finite element method. A 3-dimensional (3D) finite element model of a lower first premolar was developed. We used the image software Geomagic Studio (3D Digital 2002; Geomagic, Research Triangle Park, NC, USA) to reduce the post diameter by 6 ratios to a root diameter of 20, 30, 40, 50, 60, and 80% and then individually implemented them into the root of a tooth. A chewing static force of 100 N was applied as a 45° diagonal load on the buccal cusp tip, and the σ(von Mises) and σ(max) stresses were calculated. Analysis of the σ(von Mises) values revealed that the stresses were concentrated in the middle 1/3 of both the post and the root surface for all models, as were the σ(max) values. The results also indicated that when the diameter of the post was 50% of that of the root, the stress distributions of the post and the root surface were most favorable. In conclusion, the clinical implications of the results will need to be further studied and discussed.

The purpose of this study is to analyze biomechanical interactions in the alveolar bone surrounding implants with smaller-diameter abutments by changing position of the fixture-abutment interface, loading direction, and thickness of cortical bone using the finite element method.Twenty different finite element models including four types of cortical bone thickness (0.5, 1, 1.5, and 2 mm) and five implant positions relative to bone crest (subcrestal 1, implant shoulder 1 mm below bone crest; subcrestal 0.5, implant shoulder 0.5 mm below bone crest; at crestal implant shoulder even with bone crest; supracrestal 0.5, implant shoulder 0.5 mm above bone crest; and supracrestal 1, implant shoulder 1 mm above bone crest) were analyzed. All models were simulated under two different loading angles (0 and 45 degrees) relative to the long axis of the implant, respectively. The three factors of implant position, loading type, and thickness of cortical bone were computed for all models.The results revealed that loading type and implant position were the main factors affecting the stress distribution in bone. The stress values of implants in the supracrestal 1 position were higher than all other implant positions. Additionally, compared with models under axial load, the stress values of models under off-axis load increased significantly.Both loading type and implant position were crucial for stress distribution in bone. The supracrestal 1 implant position may not be ideal to avoid overloading the alveolar bone surrounding implants.

Oral appliances are a range of devices that are designed to alter upper airway patency. The efficiency of these appliances for treatment of obstructive sleep apnea (OSA) has been rarely discussed. This case report describes two designs of mandibular repositioning appliances used to treat OSA. A 36-year-old man was diagnosed with mild OSA by his physician. A single-piece, soft oral appliance and a two-piece, acrylic appliance were used in this patient. Polysomnography was performed three times (baseline, and with the single-piece, and two-piece appliances). The apnea/hypopnea index was improved significantly with both appliances, but to a greater degree with the single-piece soft appliance. Our study concluded that oral appliances may assist in the management of OSA.

Background Patients who wear mandibular dentures and hold their tongues in retracted positions alter the dimensions of the sublingual space and disrupt the peripheral seal that is needed for optimal denture retention. The authors studied whether retention could be improved if patients moved their tongues from a retracted resting position to an ideal resting position. Methods The authors observed and classified the mandibular residual ridge morphologies of 85 participants who wore complete dentures. The authors recorded and compared the retention of the mandibular denture before and after repositioning the tongue to the ideal resting position. Results When the participants’ tongues were in a retracted resting position, the average retention of the mandibular denture was 75.38 gram weight (± 81.83 standard deviation [SD]). After participants repositioned their tongues to the ideal resting position, the average retention of the mandibular denture was 118.89 gw (± 93.00 SD), an increase of 57.73 percent. Conclusions In all morphological classes, when participants held their tongues in the ideal resting position, the average mandibular denture retention increased by 57.73 percent, a statistically significant improvement compared with when participants held their tongues in a retracted resting position. Clinical Implications Clinicians are encouraged to evaluate carefully the tongue resting position in all patients who wear dentures, help create reasonable therapeutic expectations by informing patients about the significant effect that tongue position will have on future denture retention and provide helpful neuromuscular training for patients with retracted-tongue habits.

Various techniques and modifications have been introduced in the treatment of mandibular prognathism. However, there are still few reports concerning long-term stability, especially using the intraoral vertical ramus osteotomy (IVRO) method. The purpose of this study was to investigate the long-term stability for correction of mandibular prognathism using IVRO. Twenty-five mandibular prognathism patients were treated by bilateral IVRO, and were evaluated cephalometrically by reference to the menton. A set of 3 standardized lateral cephalograms were obtained from each subject preoperatively (T1), immediately postoperatively (T2), and after 2 years postoperatively (T3). Relapse was defined as forward movement of menton after the 2-year follow-up. The mean setback of the menton was 12.8 mm in horizontal direction and 0.9 mm downward in vertical direction. The average follow-up was 33.9 months. The mean relapse was 1.3 mm (10.2% = 1.3 of 12.8) in forward direction and 0.6 mm in upward direction. There was no significant movement in the vertical direction. However, significant relapse was shown in the horizontal direction, even though the amount was small. The long-term stability of our present study suggested that IVRO is useful for correction of mandibular prognathism.

Clinically, many implant cases with different angulation over the lower posterior area have been found. The purpose of this study was to analyze the bony stress with different implant tilting during normal masticatory load using the finite element method (FEM), with the hope of discovering a desirable installation of implant. A three-dimensional finite element method was employed to analyze the bony stress generated by different angulation designs (15 degrees) of implant bodies. Eight solid models of the mandibular first and second molars were built up and then transferred to a mesh model in FEM (ANSYS) to perform a stress analysis. A simulated load (400 N) was applied to the splinted crowns with vertical and horizontal forces. The loading sites were on the central fossa of the splinted crowns. For stress distribution, some designs will be better than a parallel installation. The results suggested that not all implant bodies tilting with the splinted crowns lead to stress concentration.

A soft palate defect may result from surgical resection, and its consequences could include hypernasal speech and nasal regurgitation of food and liquids. A speech aid prosthesis fabricated for patients can improve nasal emission during speech, and assist in preventing nasal regurgitation of food. This article presents a case of the reconstruction of a soft palate defect by prosthetic obturation.

Purpose: The aim of this study was to explore individual (ie, sociodemographic characteristics, patient personality) and clinical factors (ie, dentist-patient communication, denture quality) associated with complete denture satisfaction among the Taiwanese elderly population. Materials and Methods: A multistage sampling and cross-sectional design was used to collect data. A total of 387 fully edentulous citizens, aged 65 years and older and who had received new sets of complete dentures, were selected. The participants completed clinical dental examinations and questionnaires by personal interview to collect information on denture satisfaction and associated variables. The relationship among three groups of these participants (satisfied, neutral, and dissatisfied) and potential factors were simultaneously examined using polytomous logistic regression analysis. Results: Overall, 36.7% of the participants were dissatisfied with their dentures. Living status (crude odds ratio [COR] = 2.04), personality (COR = 4.86), dentist-patient communication (COR = 7.46), and denture quality (COR = 5.02) were associated with complete denture satisfaction. The multivariate regression model showed that dentist-patient communication (adjusted odds ratio [AOR] = 6.41) and denture quality (AOR = 4.40) were significant complete denture satisfaction factors that diluted the effect of living status and personality. Conclusions: Inadequate dentistpatient communication and low denture quality were associated with the dissatisfaction of patients with dentures. To increase complete denture satisfaction, the importance of training programs aimed at enhancing dentist-patient communication and denture quality cannot be overemphasized.

Dens evaginatus is a developmental anomaly that produces a tubercle on the occlusal surface of a tooth. It is found most frequently in the mandibular premolars. The occlusal tubercle easily causes occlusal interferences. Attrition or fracture of the tubercle can lead to pulpitis, pulp necrosis, periapical pathosis, and periapical infection. This case report illustrates the treatment of facial cellulitis arising from dens evaginatus with open apex. Calcium hydroxide was used for the apexification procedure. One year after canal obturation, radiography revealed no apical pathosis and the apical seal was evident.

Purpose. The aim of this study was to determine the correlation between the pharyngeal airway space and head posture after mandibular setback surgery for mandibular prognathism.Materials and Methods. Serial lateral cephalograms of 37 patients with mandibular prognathism who underwent intraoral vertical ramus osteotomy (IVRO) were evaluated before (T1) and immediately (T2), between 6 weeks and 3 months (T3), and more than 1 year (T4) after surgery. Pairedt-tests and Pearson’s correlation analysis were used to evaluate the postoperative changes in all cephalometric parameters, including the mandible, hyoid, head posture (craniocervical angle), and pharyngeal airway space.Results. The mandible and hyoid were set back by 12.8 mm and 4.9 mm, respectively, at T2. Furthermore, the hyoid showed significant inferior movement of 10.7 mm, with an 8 mm increase in the tongue depth. The upper oropharyngeal airway (UOP) shortened by 4.1 mm, the lower oropharyngeal airway (LOP) by 1.7 mm, and the laryngopharyngeal airway by 2 mm. The craniocervical angle showed a significant increase of 2.8°. UOP and LOP showed a significant correlation with the craniocervical angle at T2 and T4.Conclusions. Our findings conclude that the oropharyngeal airway space is significantly decreased and correlated with a change in the head posture after mandibular setback surgery.

Background: Although the use of removable dentures can improve oral function and esthetics for elderly people, compared to those who do not wear removable dentures, those wearing removable dentures could have worse oral health related-quality of life (OHRQoL). Additional information is required to assess which factors related to denture wearing influence the OHRQoL of elderly individuals. The purpose of this study is to evaluate the association between denture wearing and OHRQoL in a sample of elderly individuals in Taiwan. Methods: The study population included 277 elderly people wearing removable dentures (mean age=76.0 years). Using face-to-face interviews, we collected data on the participants’ socio-demographic characteristics, dental care service usage (regular dental checkups, treatment during toothache, dental visits in the last year), and factors related to denture wearing (perceived oral pain, perceived loose denture, perceived oral ulcer, perceived halitosis, perceived dry mouth, and perceived total denture satisfaction scores). OHRQoL was measured using the Taiwanese version of the Geriatric Oral Health Assessment Index (GOHAI-T). The location and number of remaining natural teeth and the type of denture were also recorded. Hierarchical multiple regression analysis was performed using GOHAI-T scores as the dependent variable. Results: All the predictors together accounted for 50% of the variance in GOHAI-T scores. Further, education level, number of natural teeth, denture status, perceived loose denture, perceived oral ulcer, and perceived total denture satisfaction scores had statistically significant influences on OHRQoL. When compared with other variables, factors related to denture wearing, especially perceived total denture satisfaction scores, had the greatest impact on GOHAI-T scores. Conclusions: Of the factors analyzed in this study, denture satisfaction was the strongest predictor of OHRQoL. This suggests that denture satisfaction is useful for assessing the effect of denture treatment on the OHRQoL of elderly individuals wearing removable dentures.

Objective.To investigate the factors affecting intraoperative hemorrhage and postoperative sequelae after orthognathic surgery.Materials and Methods.Eighty patients with mandibular prognathism underwent surgical mandibular setback with intraoral vertical ramus osteotomy (IVRO). The correlation between the blood loss volume and postoperative VAS with the gender, age, and operating time was assessed using thet-test and Spearman rank correlation coefficient. The correlation between the magnitude of mandibular setback with the presence of TMJ clicking symptoms and lip sensation was also assessed.Results.The mean operating time and blood loss volume for men and women were 249.52 min and 229.39 min, and 104.03 mL and 86.12 mL, respectively. The mean VAS in men and women was 3.21 and 2.93, and 1.79 and 1.32 on the first and second postoperative days. There is no gender difference in the operating time, blood loss, VAS, TMJ symptoms, and lip numbness. The magnitude of mandibular setback was not correlated with immediate and long-term postoperative lip numbness.Conclusion.There are no gender differences in the intraoperative hemorrhage and postoperative sequelae (pain, lip numbness, and TMJ symptoms). In addition, neither symptom was significantly correlated with the amount of mandibular setback.

Developing three dimensional finite element mesh models for irregular geometric objects requires a large amount of manual efforts, hence limiting the three dimensional approach for dental structure analyses. An automatic procedure which can be used to generate a three dimensional finite element mesh for the maxillary second premolar was developed in this study. Firstly, a embedded second premolar was sliced and scanned parallel to the occlusal surface. A self-developed image processing system was employed to detect the boundaries of different materials within each section. An automatic mesh generation program was used on these boundaries to create tetrahedral elements based on moving nodes of uniform cube approach. Six mesh models of the second premolar with different element sizes using linear and quadratic elements were analyzed. Strain energy and von Mises stresses were reviewed for convergence in the crown regions.

The patient was a case of severe dentoalveolar extrusion of the right maxillary posterior segment due to early loss of mandibular molars. Therefore, it is difficult to replace the missing teeth with either fixed or removable prostheses. Her occlusion was Angle Class II malocclusion and no mandibular molars for anchorage on the right side. A posterior maxillary subapical osteotomy was utilized for reestablishing the intermaxillary space. A titanium alloy miniplate placed in the right mandible provide skeletal anchorage to distalize the anterior mandibular teeth. Dental implants were placed to restore masticatory function.

The purposes of this study were to (1) examine the relationship between the number of various types of healthy remaining natural teeth at different sites and self-rated chewing ability and (2) evaluate the relationship between the number of functional tooth units (FTUs), comprising functional natural teeth (FNT) or fixed prostheses, and self-rated chewing ability. A sample of 296 adults (122 men and 174 women), aged 45 years or older (average age, 56.6±9.7), were recruited from seven dental clinics in Kaohsiung City. Dental information on the number and status of remaining teeth was obtained through examination by trained and calibrated dentists. Self-assessment of chewing ability (masticatory score) was evaluated with a self-administered questionnaire. Results showed that increased age is associated with a greater likelihood of difficulty in chewing. To avoid chewing difficulty, at least 24.7 FNT, 13.3 posterior-FNT, 8.1 units of natural tooth-FTUs, or 9.6 units of fixed tooth-FTUs must remain. Age and the number of healthy remaining teeth, including natural teeth and fixed prostheses, are key factors in chewing ability. Given that aging is unavoidable, the preservation of healthy remaining teeth plays a relatively important role in the maintenance of chewing ability among middle-aged and elderly people.

Intraoral vertical ramus osteotomy (IVRO) and sagittal split ramus osteotomy (SSRO) have been advocated as two major procedures for the correction of mandibular prognathism. However, only a few reports with at least a 2-year follow-up period describe the long-term stability especially of the IVRO method. This study aimed to identify factors contributing to skeletal relapse after a 2-year postoperative follow-up period. A set of three standardized lateral cephalograms were obtained from each subject, taken preoperatively (T1), immediately postoperatively (T2), and 2 years postoperatively (T3). Relapse was defined as forward movement of the menton (Me) after a 2-year follow-up period. Two angular measurements (SNB and SN-occlusal plane angle) and five linear measurements (horizontal Me, vertical Me, overbite, anterior facial height, and mandibular length) were compared immediately after the operation and at the 2-year follow-up visit. The mean setback of the menton was 12.8 mm, and the mean relapse was 1.3 mm (10.2% = 1.3/12.8). The magnitude of the setback was not significantly accounted for in the relapse. There were weak correlations between the relapse and the concerned factors, namely, overbite, anterior facial height, mandibular length SNB, and SN-occlusal plane angle). The current study confirmed the stability of IVRO in the treatment of mandibular prognathism.

Conical crown-retained dentures (CCRD) show a higher survival rate and greater patient satisfaction than transitional removable partial dentures during long-term follow-up. However, unsustainable denture retention force on supporting abutments after initial delivery and loss retention are frequently seen in long-term follow-up of clinical cases. The main causes are insufficient information concerning denture retention designs and the retention-tolerance of the supporting abutments. Monitoring by dental technicians of the quality of dental prostheses is critical. This case report describes an optimal method for CCRD construction that determines and distributes an optimal denture retention force on the supporting abutments to allow the patient to easily remove the denture while ensuring that the CCRD remains in place during physiologic activities. Oral rehabilitation with CCRD should consider the condition of the abutment periodontal support, the interarch occlusal relationship, supplemental fatigue of the terminal abutment, and patient's estimated bite force. The effects of friction on the abutment's inner crown were based on an optimal a angle. The dental laboratory used these measurements to fabricate a CCRD using a Koni-Meter to adjust the retention of the inner crown. This method protects the abutments and reduces the wear between the inner and outer crowns. The CCRD achieved good esthetic results and physiologic functions. Periodic long-term follow-up of the patient and CCRD after initial placement is recommended.

During orthodontic therapy, patients frequently complain about pain and discomfort, especially during insertion of fixed appliances. Skeletal anchorage using an interdental microimplant is a new concept in orthodontic treatment. The purpose of this study was to investigate differences and changes in the level of pain among patients in relation to orthodontic microimplant treatments. Forty microimplants were applied to the maxilla as skeletal anchors in the orthodontic treatment. The visual analog scale (VAS) was used to evaluate the patients’ perception of pain during this new modality treatment. The premolar extraction VAS core was used as a baseline for the complete orthodontic procedure. The mean VAS score was 35.8 mm at 24 h after premolar extraction. The mean VAS score for insertion and removal of the microimplant 24 h after the operation was 12.3 and 7.8 mm, respectively. Three months after removal of the skeletal anchors, the VAS score had decreased to 3.2 mm and was the same as with the traditional orthodontic treatment. By using the repeated-measure general linear model (GLM), we found that the score 1 day after microimplant placement was significantly less than that 1 day after first premolar extraction or that 1 day after fixed appliance insertion. This result indicates that interdental microimplant did not generate any greater pain than other orthodontic procedures. Therefore, patients were willing to adopt the new orthodontic treatment.

Objectives . The objective of this study was to use a three-dimensional (3-D) finite element model to investigate normal stress distribution to substantiate the tooth flexure mechanism. The study also compared the changes in the stresses by different occlusal loading sites and directions. Methods . The 3-D finite element analysis was used. A maxillary premolar was selected to construct the simulation model. The model was constructed step-by-step for convergence and validity. Seven load conditions for various load sites and different directions were simulated to the model. Results . The maximal principal stress and minimal principal stress distributions developed within the structures of seven load conditions were output and their stress distributions on z -plane at the vertical midline were shown. The peak tensile stress of the cervical area for various load conditions were compared and listed. Conclusions . This study has shown that the presence of tensile stresses in the cervical region of a maxillary premolar by various loading sites and different directions. The results coincided with the stress-induced theory, hence sustaining it. The relationship of the affected factors of leverage to the development of cervical abfraction lesions, was explored.

Maxillary molars can over-erupt when their antagonists are lost and there are no replacements. When the opposing molars severely extrude into the edentulous space, it is difficult to replace the missing teeth with either fixed or removable prostheses. We present the following case report, providing a solution for this type of problem. A two-stage posterior subapical osteotomy was used to reestablish the intermaxillary space. Following orthodontic treatment and implant placement, the patient regained occlusal harmony and normal masticatory function.

Miniplate and screw devices are widely used for fracture repair and fixation of osteotomies. Currently, these miniplate systems are being used as orthodontic treatments for skeletal anchorage. However, despite the widespread use of these treatments, patients are apprehensive when they need to undergo miniplate procedures. Recently, we assessed pain perception using the visual analog scale (VAS) score (0-100 mm) in patients who had undergone miniplate procedures. Thirty miniplates were positioned in the maxilla as skeletal anchors for orthodontic treatment. On the first day after insertion of the fixed orthodontic appliances, the mean VAS score was 36.3 mm. The mean VAS score at 24 hours after insertion of the miniplate was 58 mm. Three months after orthodontic force was applied to the miniplate, the mean VAS scores during eating and speaking gradually decreased to 20 mm and 15 mm, respectively. The mean VAS score at 24 hours after removal of the miniplate was 41.3 mm. Three months after removal of the skeletal anchors, the VAS score decreased to 5 mm. Eighty-eight percent of patients stated that they would be prepared to undergo these new and more efficient treatment modalities in the future. The miniplate system was successfully used in this study as a skeletal anchor, and the patients could endure the pain and discomfort of this orthodontic treatment.