bluuebunny/crossref_metadata_2025_split huggingface dataset:
Increased Occurrence of Dental Anomalies Associated with Second-Premolar Agenesis
Authors: Garib Daniela G. , Peck Sheldon , Gomes Simone Carinhena 
Published: October 2008

Abstract
Objective: To evaluate the prevalence of dental anomalies in patients with agenesis of second premolars and compare the findings with the prevalence of these anomalies in the general population.
Materials and Methods: A Brazilian sample of 203 patients aged 8 to 22 years was selected. All patients presented agenesis of at least one second premolar. Panoramic and periapical radiographs and dental casts were used to analyze the presence of other associated dental anomalies, including agenesis of other permanent teeth, ectopia of unerupted permanent teeth, infraocclusion of deciduous molars, microdontia of maxillary lateral incisors, and supernumerary teeth. The occurrence of these anomalies was compared with occurrence data previously reported for the general population. Statistical testing was performed using the chi-square test (P &lt; .05) and the odds ratio.
Results: The sample with agenesis of at least one second premolar presented a significantly increased prevalence rate of permanent tooth agenesis (21%), excluding third molars. Among the sample segment aged 14 years or greater (N = 77), occurrence of third-molar agenesis (48%) exceeded twice its normal frequency. Significant increases in occurrence of microdontia of maxillary lateral incisors (20.6%), infraocclusion of deciduous molars (24.6%), and distoangulation of mandibular second premolars (7.8%) were observed. Palatally displaced canine anomaly was also significantly elevated (8.1%).
Conclusion: The results provide evidence that agenesis of other permanent teeth, microdontia, deciduous molar infraocclusion, and certain dental ectopias are the products of the same genetic mechanisms that cause second-premolar agenesis.
Impaction and Retention of Second Molars: Diagnosis, Treatment and Outcome
Authors: Magnusson Cathrine , Kjellberg Heidrun 
Published: October 2008

Abstract
Objective: To evaluate treatment outcome in patients with second molar impaction and retention.
Materials and Methods: A total of 135 second molars, 65 in the maxilla and 70 in the mandible were collected from 87 patients (45 girls and 42 boys) with a mean age of 15 years (range: 11– 19 years). Available patient records, x-rays, study casts, and photos were studied. The mean follow-up period was 22 months (range: 4–106 months).
Results: A total of 166 second molars were diagnosed as impacted, 24 as primary and 5 as secondarily retained; 80% of the second molars were orthodontically or surgically treated. In more than half of the treated patients the second molars failed to erupt into a proper position. Surgical exposure of the retained or impacted second molar was the treatment found most successful (71%). The least successful treatment (11%) used the third molar to replace the second molar after the second molar was extracted. No clear difference in treatment outcome could be detected between the impacted and the primary or secondary retained teeth. However, a clear difference was found between the impacted and the primary retained second molars regarding treatment strategy: 9% of the impacted and 67% of the primary retained teeth were left untreated. Dental crowding was found in 70% of the patients.
Conclusion: In more than half of the treated patients the second molars failed to erupt into a proper position. The most common treatment given (extraction of the second molar) was the least successful.
Third-Order Torque and Self-Ligating Orthodontic Bracket–Type Effects on Sliding Friction
Authors: Chung Michael , Nikolai Robert J. , Kim Ki Beom , Oliver Donald R. 
Published: October 2008

Abstract
Objective: To examine the influence of third-order torque on kinetic friction in sliding mechanics involving active and passive self-ligating brackets.
Materials and Methods: Wire-slot frictional forces were quantified and compared across five sets of brackets and tubes within a simulated posterior dental segment with −15°, −10°, −5°, 0°, +5°, +10°, and +15° of torque placed in the second-premolar bracket; a working archwire was pulled through the slots.
Results: Increasing the torque from 0° to ±15° produced significant increases in frictional resistance with all five sets of brackets and tubes. At 0° and ±5° of torque, generally less friction was created within the passive than within the active self-ligating bracket sets, and the conventional bracket sets with elastomeric ligation generated the most friction. At ±10° of torque, apparently with wire-slot clearance eliminated, all bracket-and-tube sets displayed similar resistances, with one exception at +10°. At ±15° of torque, one passive set and one active set produced significantly larger frictional resistances than the other three sets.
Conclusions: Third-order torque in posterior dental segments can generate frictional resistance during anterior retraction with the archwire sliding through self-ligating bracket slots. With small torque angles, friction is less with passive than with active self-ligating brackets, but bracket design is a factor. Frictional forces are substantial, regardless of ligation if the wire-slot torque exceeds the third-order clearance.
Biomechanical and Histomorphometric Characterizations of Osseointegration during Mini-Screw Healing in Rabbit Tibiae*
Authors: Wu Jing , Bai Yu-Xing , Wang Bang-Kang 
Published: October 2008

Abstract
Objective: To evaluate effects of different healing times on integration of titanium mini-screws and bones under unloaded conditions.
Materials and Methods: Biomechanical stability measurements and histomorphometric observations were performed in a rabbit tibia model after different healing times: 0 (immediate) and 1, 2, 4, and 8 weeks.
Results: Biomechanical stability and both maximum torque and maximum pullout load increased with healing time but increased significantly only after 4 weeks. Maximum torque and maximum pullout load both significantly correlated with healing time and with each other. Similarly, histomorphometric analyses showed that new bone formation increased with healing time but increased dramatically only after 4 weeks. The data may provide guidance for determining optimal implant plans in clinical practice.
Conclusion: Mini-screw healing is a continuous process, and week 4 is a critical time point in this process.
Effects of Ovariectomy on Rat Genioglossal Muscle Contractile Properties and Fiber-Type Distribution
Authors: Liu Yue-hua , Jia Shan-shan , Hou Yu-xia 
Published: October 2008

Abstract
Objective: To test the hypothesis that ovariectomy has no effects on contractile, histochemical, or biochemical properties of the rat genioglossus (GG).
Materials and Methods: Eight-week-old female Sprague-Dawley rats were randomly assigned into three groups: normal group (Normal), sham-operated group (Sham), and ovariectomized group (OVX). Four weeks later, genioglossal electromyography activity (EMGgg) and contractile properties were measured, including relative integrated EMG (iEMG), maximal twitch tension, 70%-decay time, and fatigue index (FI). Then rats were sacrificed and paired GG were removed for further analysis. Adenosine-triphosphatase (ATPase) staining was performed to determine the percent fiber-type distribution and to identify cross-sectional area (CSA) of muscle fibers. Myosin heavy chain (MHC) phenotypes were determined by gel electrophoresis.
Results: Ovariectomy reduced EMG activity and contractile properties of the GG. Following ovariectomy, the CSA of type IIA and the proportion of MHCIIA decreased significantly. The MHC isoform composition of GG transferred from relative slow-twitch to fast-twitch isoform, following the order MHCIIB → MHCIIX → MHCIIA. Sham operation had no effect on any of the parameters.
Conclusions: The hypothesis is rejected. The contractile properties of the GG are sensitive to ovariectomy. These changes were, at least in part, associated with changes in the amount and type of contractile protein expressed.
Use of Palatal Miniscrew Anchorage and Lingual Multi-Bracket Appliances to Enhance Efficiency of Molar Scissors-Bite Correction
Authors: Tamamura Nagato , Kuroda Shingo , Sugawara Yasuyo , Takano-Yamamoto Teruko , Yamashiro Takashi 
Published: October 2008

Abstract
This article reports the successful treatment method of scissors-bite correction using miniscrew anchorage and a lingual multi-bracket appliance. A female patient, 17 years and 4 months old, had a chief complaint of crowding of anterior teeth. The patient was given the diagnosis of Angle Class I malocclusion with bimaxillary protrusion and incisor crowding. She also showed a scissors-bite of the second molar on the right side. Miniscrews were inserted into the palatal region of the upper second molar to reinforce the anchorage, and a lingual multi-bracket appliance was placed into the maxilla. Miniscrews inserted palatally were used to correct the scissors-bite in the first 3 months; afterward, they were used to retract the six anterior teeth. The total active treatment period was 26 months. Because of the bite-plane effect, the upper and lower molars were separated in occlusion, and the scissors-bite was corrected effectively within a short time. The combined use of palatal miniscrew anchorage and lingual multi-bracket appliances enhances efficiency of molar scissors-bite correction.
Acceptability of Dental Appearance in a Group of Finnish 16- to 25-Year-Olds
Authors: Svedström-Oristo Anna-Liisa , Pietilä Terttu , Pietilä Ilpo , Vahlberg Tero , Alanen Pentti , Varrela Juha 
Published: October 2008

Abstract
Objective: To define a grade in the Aesthetic Component (AC) of the Index of Orthodontic Treatment Need (IOTN) that would differentiate between esthetically acceptable and unacceptable occlusions and that would also be both subjectively and objectively meaningful.
Materials and Methods: Dental appearance and self-perceived orthodontic treatment need were analyzed in a group of Finnish young adults (171 males, 263 females, age range 16–25 years). Subjective data were gathered using a questionnaire, and the respondents were requested to score their dental appearance on a visual analog type 10-grade scale. Professional assessment of dental appearance was performed by two orthodontists using the AC of the IOTN. The cutoff value between esthetically acceptable and unacceptable occlusions was defined using receiver operating characteristic curves.
Results: Sixty-six percent of orthodontically treated and 74% of the untreated respondents were satisfied with their own dental appearance. Every third respondent reported one or more disturbing traits in their dentition. The most frequently expressed reason for dissatisfaction was crowding; girls expressed dissatisfaction more often than boys did (P = .005). A self-perceived treatment need was reported infrequently by 8% of orthodontically treated and 6% of untreated respondents. In the logistic regression analysis, self-perceived need for orthodontic treatment was the only significant factor explaining dissatisfaction with own dental esthetics. On the applied scales, grades 1 and 2 fulfilled the criteria for satisfactory dental esthetics.
Conclusion: The results suggest that the AC grade 3 could serve as a cutoff value between esthetically acceptable and unacceptable occlusions.
Disk Position and Temporomandibular Joint Structure Associated with Mandibular Setback in Mandibular Asymmetry Patients
Authors: Kawakami Masayoshi , Yamamoto Kazuhiko , Inoue Tomohiro , Kajihara Atsuhisa , Fujimoto Masaki , Kirita Tadaaki 
Published: October 2008

Abstract
Objective: To determine the changes in articular disk position and the temporomandibular joint (TMJ) structure in patients who had an asymmetric setback of the mandible performed by a bilateral sagittal split ramus osteotomy with manual positioning of the condyle.
Materials and Methods: Twenty-two patients with skeletal Class III malocclusion being treated at Nara Medical University Hospital were evaluated using clinical examination and pre- and postoperative magnetic resonance images of their TMJs.
Results: Changes in articular disk position after asymmetric setback surgery were not statistically significant, although a tendency of anterior displacement in the fossa was noted. The anterior and posterior joint spaces did not show significant changes, whereas the condyle head of the deviated or contralateral side tended to be positioned downward.
Conclusion: The asymmetric setback of the mandible with intraoperative manual positioning of the condyle does not significantly change the disk position in the fossa.
Overjet at the Anterior and Posterior Segments: Three-Dimensional Analysis of Arch Coordination
Authors: Kook Yoon-Ah , Bayome Mohamed , Park Soo-Byung , Cha Bong-Kuen , Lee Young-Wuk , Baek Seung-Hak 
Published: October 2008

Abstract
Objectives: To compare the amounts of anatomical overjet measured from facial axis (FA) points with the amounts of bracket overjet measured from bracket slot center (BSC) points.
Materials and Methods: The samples consisted of 27 subjects with normal occlusion whose models were fabricated with a three-dimensional (3D) scanner and the 3Txer program (Orapix Co Ltd, Seoul, Korea). 3D virtual brackets (0.022″ Slot, MBT setup, 3M Unitek, Monrovia, Calif) constructed with a 3D-CAD program were placed on an FA point with the 3Txer program. The arch dimension and the amounts of overjet from FA and BSC points were measured. Paired t-tests and analysis of variance (ANOVA) tests were used for statistical analysis.
Results: No significant difference in arch width and depth was observed between FA and BSC points. Although the amounts of overjet measured from FA points showed homogenous distribution, a tendency to decrease from the anterior segment (2.3 mm) to the posterior one (2.0 mm) was noted. However, the amounts of overjet measured from BSC points were variable, especially in the premolar and molar areas. Significant discrepancies in the amounts of overjet in most of the areas between FA and BSC points (more than P &lt; .05), except the lower second premolar and second molar areas, were reported, even though insets and offsets are part of the prescription for the base of straight-wire appliance (SWA) brackets.
Conclusions: The hypotheses that the amount of overjet measured from BSC points was 3 mm through the whole segments and that distribution of the amounts of overjet from BSC points was the same as that from FA points were rejected.
Change of Incisor Inclination Effects on Points A and B
Authors: Al-Abdwani Rasha , Moles David R. , Noar Joseph Harold 
Published: October 2008

AbstractObjective: To identify and evaluate changes in the cephalometric position of points A and B due to an incisal inclination change caused by orthodontic treatment.Materials and Method: A total of 103 pairs of consecutive pretreatment and posttreatment lateral cephalographs that met the inclusion criteria were systematically collected from the departmental database and digitized using a customized software program (Gela). Repeatability analyses showed good reliability and no evidence of bias. A statistical model was generated using a Generalized Estimating Equation approach to analyze the data accounting for growth and bodily movement because both factors influence the position of points A and B (P &lt; .001, P &lt; .001). Changes in tooth length were also accounted for, as these changes may influence the calculated position of the centroid (P = .002).Results: Each 10° change in the maxillary incisor inclination results in a statistically significant average change in point A of 0.4 mm in the horizontal plane (P = .028). Each 10° change in the mandibular incisor inclination results in a borderline statistically significant average change in point B of 0.3 mm in the horizontal plane (P = .058). There were no significant changes in the vertical position of points A and B.Conclusion: The effects of incisal inclination changes, due to orthodontic treatment, are of no clinical relevance to the position of point A and B, even though they may be statistically significant. The validity of points A and B as skeletal landmarks generally holds true, and accounting for treatment changes is unnecessary.
The Impact of Malocclusion/Orthodontic Treatment Need on the Quality of Life
Authors: Liu Zhijian , McGrath Colman , Hägg Urban 
Published: October 2008

Abstract
Objective: To assess the current evidence of the relationship between malocclusion/orthodontic treatment need and quality of life (QoL).
Materials and Methods: Four electronic databases were searched for articles concerning the impact of malocclusion/orthodontic treatment need on QoL published between January 1960 and December 2007. Electronic searches were supplemented by manual searches and reference linkages. Eligible literature was reviewed and assessed by methodologic quality as well as by analytic results.
Results: From 143 reviewed articles, 23 met the inclusion criteria and used standardized health-related QoL (HRQoL) and orthodontic assessment measures. The majority of studies (18/23) were conducted among child/adolescent populations. Seventeen of the papers were categorized as level 1 or 2 evidence based on the criteria of the Oxford Centre for Evidence-Based Medicine. An observed association between HRQoL and malocclusion/orthodontic treatment need was generally detected irrespective of how they were assessed. However, the strength of the association could be described as modest at best. Key findings and future research considerations are described in the review.
Conclusions: Findings of this review suggest that there is an association (albeit modest) between malocclusion/orthodontic treatment need and QoL. There is a need for further studies of their relationship, particularly studies that employ standardized assessment methods so that outcomes are uniform and thus amenable to meta-analysis.
A Novel Method for the Assessment of Three-Dimensional Tooth Movement during Orthodontic Treatment
Authors: Jang Insan , Tanaka Motohiro , Koga Yoshiyuki , Iijima Seiko , Yozgatian Joseph H. , Cha Bong Kuen , Yoshida Noriaki 
Published: October 2008

AbstractObjective: To (1) evaluate the stability of palatal rugae as landmarks for superimposition of dental casts and (2) establish a three-dimensional superimposition method of maxillary dental casts for analyzing orthodontic tooth movement.Materials and Methods: The sample consisted of dental casts obtained from 10 patients treated with extraction of bilateral maxillary first premolars and placement of three palatal miniscrews as anchorage for retraction of the anterior teeth. Dental casts were measured by means of laser surface scanning system, and three-dimensional images were reconstructed. Serial dental casts were superimposed on the three miniscrews as registration landmarks (miniscrew-superimposition method), and the displacement of each palatal ruga point during the closure of extraction spaces was measured. Displacement of the central incisors was measured by the miniscrew-superimposition method and the proposed superimposition technique (ruga-palate-superimposition method). Correlation analysis and paired t-tests were performed to determine whether a significant difference existed between the measurements of the two superimposition methods.Results: The medial points of the third palatal rugae and the shape of the palatal vault were stable throughout the treatment. The displacement of the central incisors measured using the ruga-palate-superimposition method showed no significant difference with that measured using the miniscrew-superimposition method.Conclusion: The maxillary dental casts can be reliably superimposed on the medial points of the third palatal rugae and the palatal vault as reference landmarks.
The Association of Malocclusion Complexity and Orthodontic Treatment Outcomes
Authors: Pulfer Ryan M. , Drake Carl T. , Maupome Gerardo , Eckert George J. , Roberts W. Eugene 
Published: October 2008

Abstract
Objective: To determine the relationship of the ABO Discrepancy Index (DI) to outcomes for routine malocclusions, and to ascertain whether significant trends in DI scores could be noted among annual samples of patients taken from 1998 to 2004.
Materials and Methods: A total of 716 consecutive patients with permanent dentition from a large urban graduate orthodontics program were sampled over the 7-year span. A group of six researchers with a dental background were trained and calibrated in the various components of the DI method to ensure reproducible criteria and accurate recording of clinical and radiographic data across researchers. Data management and analyses were undertaken by two other investigators who were not involved in data coding.
Results: Only a weak positive association was seen between the DI and Objective Grading System (OGS) and Comprehensive Clinical Assessment (CCA) scores. The DI was not significantly related to a general time trend.
Conclusion: The DI was found to be a reliable and relatively stable index for measuring malocclusion complexity in annual samples of patients. Although the DI is significantly related to outcomes for the most severe malocclusions, it was not a good predictor of outcome for more routine malocclusions. If the minimal acceptable outcome is defined as 30 OGS points, the mean DI (15.7) and the average OGS score (28.2) indicate that many of the malocclusions in patients in the present sample were of potential board quality.
Influence of Radiographic Position of Ectopic Canines on the Duration of Orthodontic Treatment
Authors: Fleming Padhraig S. , Scott Paul , Heidari Negan , DiBiase Andrew T. 
Published: October 2008

Abstract
Objective: To investigate the influence of radiographic position of palatally impacted canines on the length of treatment for orthodontic alignment.
Materials and Methods: Treatment records of 45 consecutive successfully treated patients (36 unilateral, 9 bilateral) with ectopic palatal canines treated with surgical exposure and orthodontic traction were analyzed. The sample was based on orthodontic referrals over a 3-year period in Kent and Canterbury Hospital, UK. The duration of treatment was related to radiographic parameters including the height of the impacted canine, angulation of the long axis to the upper midline, mesiodistal position of the canine tip relative to the midline and adjacent incisors, and the anteroposterior position of the canine root apex.
Results: Using multiple stepwise regression analysis, the horizontal position of the canine crown relative to adjacent teeth and maxillary dental midline showed a statistically significant correlation with the duration of treatment (P =.042), explaining 7.7% of the overall variance. However, treatment duration was found to be independent of the initial canine angulation (P = .915), vertical height (P =.065), and position of the canine apex (P = .937).
Conclusions: Accurate prediction of treatment duration for orthodontic alignment of palatally impacted maxillary canines is difficult. However, the mesiodistal position of the canine may be a useful predictor of treatment duration. (Angle Orthod. 2009:79;442–446.)