Interpremolar Distance Research Articles

Sex determination and odontometric dimensions - A study of a North Indian population.

Sex determination is an indispensable parameter in identifying unknown deceased individuals. It can narrow down the chances of possible matches by 50%, providing a crucial lead in personal identification. In cases of commingled, decomposed, fragmented, charred and unidentifiable corpses, the importance of dental morphometrics cannot be overlooked due to the resistance of teeth to post-mortem degradation. Addressing this quality of teeth, a descriptive cross-sectional study was conducted in a North Indian population to evaluate sexual variations in dental dimensions and to identify the most sexually dimorphic dental dimension. The study included 207 participants (114 females and 93 males) in the age group of 21 to 45 years. Dental casts were prepared after obtaining informed consent from the participants and ethical clearance from the institute's ethical committee. Six odontometric dimensions, namely incisor-incisor distance, inter canine distance, combined width of central incisors, inter-premolar distance, inter-molar distance, and dental arch height of each participant were recorded on the dental casts using standard procedures. Analysis of the data elucidated the existence of statistically significant sexual dimorphism in the dental dimensions of the participants. The results of the discriminant function analysis show a sex determination accuracy of 68.1%, with a cross-validation accuracy of 65.2%. The study found the incisor-incisor distance to be the most sexually dimorphic trait, making it the best predictor of sex in the present population. The results of the present study may be helpful in sex determination and personal identification from dental remains in medico-legal and disaster victim identification cases.

Headgear therapy in children with Class II malocclusion and the role of compliance on treatment outcome: A nine-month randomized controlled trial.

To evaluate three-dimensional movements of maxillary teeth during headgear treatment in Class II growing children, using digital analytical tools, and to determine the effects of compliance on these movements. A 9-month parallel-group randomized controlled trial was carried out on 40 children with Class II malocclusion, aged 8-12 years, half assigned to receive a cervical headgear and half to a no-treatment group, using block randomization. Subjects in the treatment group were instructed to wear the headgear for 12 hours daily and monitored using an electronic module. After 9 months, the following dental outcomes were measured: first maxillary molar distalisation, rotation, tip and torque, arch depth, and interpremolar and intermolar distances. Caregivers and participants were not blinded to group assignments, but those assessing outcomes were. Linear regression models were used to detect differences between groups and correlation coefficients to find correlations between compliance and dental outcomes. All 40 included patients were analysed. A significant difference in molar distalisation was observed between the treatment (1.2 mm) and control groups (-0.2 mm). Arch depth change was also increased to a larger extent in the treatment groups (1.3 mm vs 0.1 mm), as was the interpremolar distance (1.9 mm vs 0.4 mm). In contrast, no significant differences in molar rotation or torque change were observed. With regard to compliance, average compliance was 55%. A significant correlation was found between molar distalisation and compliance in the treatment group. Headgear therapy has significant effects on molar distalisation, arch depth, and arch width. Compliance has a significant positive effect on molar distalisation.

Relationship between OSA pathophysiological phenotypes and treatment response to mandibular advancement devices: a pilot study.

We assessed whether critical pathophysiological phenotypes predict treatment response in patients with obstructive sleep apnea using a mandibular advancement device (MAD). Thirty-one patients with obstructive sleep apnea were treated with a MAD. Individuals were categorized and graded into 4 pathophysiological phenotypes based on polysomnographic features (anatomical, ventilatory control, arousal threshold, and muscle responsiveness). Morpho-anthropometric data were additionally assessed. Patients were classified as responders or nonresponders. Associations between polysomnographic phenotypes and treatment response were documented, as were morpho-anthropometric data and their impact on therapeutic success. There was a male predominance (64.5%), with a median age of 49 years (25th percentile: 40; 75th percentile: 55), body mass index = 27.4 kg/m2 (25th percentile: 26; 75th percentile: 28.8), and apnea-hypopnea index of 18.2 events/h (25th percentile: 11.7; 75th percentile: 27.6). The majority of patients treated with a MAD (58%) were good responders (68.0% mild and moderate vs 16.7% severe). Treatment response was associated with shorter intermolar and interpremolar distances in the lower arch (P = .0092 and .0129). Rapid eye movement sleep apnea-hypopnea index and MAD-related treatment response were inversely correlated (P = .0013). Favorable anatomical (P = .0339) and low muscle response (P = .0447) phenotypes were correlated with outcomes. According to our results, a favorable response occurred in a better "anatomical phenotype" and in the worse "muscular responsiveness phenotype" according to polysomnographic data. Furthermore, other favorable predictors, such as a rapid eye movement sleep apnea-hypopnea index < 16 events/h and a smaller distance between lower molars and premolars, were found. These findings indicate that clinical and polysomnographic aspects can discriminate phenotypes that may guide decisions on MAD treatment for obstructive sleep apnea. Manetta IP, Duarte BB, Nucci LB, Enes CC. Relationship between OSA pathophysiological phenotypes and treatment response to mandibular advancement devices: a pilot study. J Clin Sleep Med. 2024;20(8):1321-1330.

Ratio of the transversal dimensions of the dental arch to the index parameters: An experimental clinical study

BACKGROUND: The incidence of malocclusion is increasing annually, which is accompanied by an increase in the number of orthodontic treatment visits. Qualitative diagnostics is the key to successful treatment and an important stage in the prevention of complications, such as recessions, root resorption, and ankylosis.&#x0D; AIM: To perform a comparative analysis of the indices for assessing the transversal parameters of the dentition for residents of St. Petersburg and the Leningrad region.&#x0D; MATERIALS AND METHODS: The width of the combined incisor and the width of the premolars and molars were measured according to the method proposed by A. Pont. Then, the parameters obtained and calculated using the index was compared. All data were statistically processed.&#x0D; RESULTS: Diagnostic models of 200 patients who fit the criteria for inclusion in the study were used. The results revealed that the index values of the width for patients in our region did not match. Thus, the interpremolar distance was on average 1.5 mm less than that calculated by the index, and the intermolar distance was 1.25 mm less.&#x0D; CONCLUSION: Further research is needed to identify new guidelines to increase the reliability of diagnostic measures.

Transverse Maxillary Deficiency Predicts Increased Upper Airway Collapsibility during Drug-Induced Sleep Endoscopy.

To examine the relationship between craniofacial skeletal anatomy and objective measures of pharyngeal collapse obtained during drug-induced sleep endoscopy. We hypothesized that transverse maxillary deficiency and an increased pharyngeal length will be associated with higher levels of pharyngeal collapsibility. Cross-sectional analysis in a prospective cohort. University Hospital. A cross-sectional analysis was conducted in a cohort of consecutive patients from the positive airway pressure(PAP) alternatives clinic who underwent computed tomography (CT) analysis and drug-induced sleep endoscopy for characterization of upper airway collapsibility. PAP titration was used to determine pharyngeal critical pressure (PCRIT ) and pharyngeal opening pressure (PhOP). CT metrics included: Transverse maxillary dimensions (interpremolar and intermolar distances) and pharyngeal length (posterior nasal spine to hyoid distance). The cohort (n = 103) of severe obstructive sleep apnea (Apnea and Hipopnea Index 32.1 ± 21.3 events/h) was predominantly male (71.8%), Caucasian (81.6%), middle-aged (54.4 ± 14.3 years), and obese (body mass index[BMI] = 30.0 ± 4.9 kg/m2 ). Reduced transverse maxillary dimensions were associated with higher PCRIT (intermolar distance: β [95% confidence interval, CI] = -.25 [-0.14, -0.36] cmH2 O/mm; p = .03) and PhOP (Interpremolar distance: β = -.25 [-0.14, -0.36] cmH2 O/mm; p = .02). Longer pharyngeal length was also associated with higher PCRIT (β = .11 [0.08, 0.14] cmH2 O/mm, p = .04) and PhOP (β [95% CI] = .06 [0.03, 0.09] cmH2 O/mm, p = .04). These associations persisted after adjustments for sex, age, height, and BMI. Our results further the concept that skeletal restriction in the transverse dimension and hyoid descent areassociated with elevations in pharyngeal collapsibility during sleep, suggesting a role of transverse deficiency in the pathogenesis of airway obstruction.

Estimation of human somatype using inter-canine and inter-premolar distances of the maxillary arch.

The establishment of a correlation between tooth dimensions and body size is crucial within the realm of forensic odontology. While numerous investigations have focused on the association between tooth morphology or width and stature, limited reports exist regarding the correlation between overall body structure or build and odontogenic parameters. This study focuses on finding a correlation between inter-arch dimensions and the body build of an individual. This study aimed to examine the potential correlation between an individual's somatotype (body build) and the measurements of inter-canine and inter-premolar maxillary arch widths. Dayananda Sagar College of Dental Sciences. A cross-sectional study. The sample size of the study was 153 individuals aged 18-25 years. Impressions for the maxillary arch were taken, study models were made and inter-arch measurements were taken using a digital Vernier calliper. For body build measurements, Heath-Carter somatotype measuring technique was used. The collected data were entered into an Excel sheet, and statistical analysis was done. Principal component analysis. On using principal component analysis, it was seen that there exists no correlation between body build of an individual when compared to inter-canine and inter-premolar distances. While no positive correlation has been seen between the odontometric parameters and specific body type, it can be argued that this can be due to the cited limitations of the study. Hence, we conclude with the note that a more detailed study would offer more viable and credible results.

Tongue Adaptation and Airway Changes in Two Different Bracket Systems: A Randomised Clinical Trial

Introduction: Orthodontics apart from correcting the malocclusions provide an invariably indirect effects on surrounding musculature and airway by means of creating room for proper tongue posture which helps in improvement of oropharyngeal airway dimensions along with dentoalveolar corrections which in this study was experimented with two different bracket systemsMBT and Damon self-ligating systems. Aim: To assess the adaptation of tongue and oropharyngeal airway changes following treatment with two different bracket systems. Materials and Methods: This randomised clinical trial was conducted in the Department of Orthodontics, Saveetha Dental College and Hospital, Chennai, Tamil Nadu, India, and included 20 participants and categorised into two groups: Group 1 and group 2 included participants who underwent orthodontic treatment with Damon appliance therapy with Damon Copper NiTi (CuNiTi) wires and MBT prescription with Damon CuNiTi wires. Lateral cephalogram and intraoral scanning was done at the start of orthodontic treatment (T0) and after one year (T1). Cephalometric and occlusal model assessment to determine the adaptation of tongue and Oropharyngeal Dimensions (OD) were determined (T0-T1) using the Facad® and 3-shape software. Independent t-tests and paired t-tests were done to compare T0 and T1 for both the groups were done using Statistical Package for the Social Sciences (SPSS) software. Results: Results of paired t-tests showed a statistically significant difference at the Interpremolar distance (IPM1) region of both groups 1 and 2 between T0 and T1 (p=0.034, p=0.011), Intercanine distance (IC) of group 2 upper (p=0.043) and IPM2 of both the groups in the upper arch (p=0.042, p=0.022). Cephalometric results showed a significant increase in all the assessed parameters within the groups between T0 and T1 (p&lt;0.05). Oropharyngeal space did not show any difference in both the systems however comparatively increased in group 1 than in group 2. Conclusion: Treatment with Damon and MBT prescriptions with Damon Cuniti wires showed significant alterations in adaptation of tongue and oropharyngeal space and also in bringing about arch expansion in maxilla and mandible with the greatest expansion noted for first premolar of both the groups and IC and Interpremolar (2nd premolar) width of the upper arch of both the groups.

Stature estimation using the odontometric measurements of the maxilla.

Stature is the height of an individual in an upright position. It is one of the key characteristics, which helps in defining any individual. Stature estimation is needed mostly in medicolegal cases where only a limited number of human fragments are left for forensic analysis. The teeth provide essential measurements that can be used to determine stature. The aim of the study is to find out whether the second maxillary interpremolar distance can be used to effectively estimate stature of individuals. For the study, the sample size taken was 60 (30 male and 30 females), and their second maxillary interpremolar distance was measured using a digital vernier caliper. The collected data were tabulated and statistical analysis was done using SPSS software (23), followed by linear regression. For male: Y = 178.65 - 1.09X, correlation coefficient, r = 0.05, For female: Y = 169.30 - 1.99X, correlation coefficient, r = 0.13. Since r < 0.2, there is no correlation between the interpremolar distance of the second maxillary premolar and the stature. From our study, we conclude that the interpremolar distance of the second maxillary premolar cannot be a reliable parameter for stature estimation in both genders.

Indirect vs direct bonding of mandibular fixed retainers in orthodontic patients: Comparison of retainer failures and posttreatment stability. A 5-year follow-up of a single-center randomized controlled trial

This 2-arm parallel trial aimed to assess the number of failures of mandibular fixed retainers bonded with direct and indirect bonding methods at a 5-year follow-up and investigate the stability of intercanine and interpremolar distances. Consecutive patients from the clinic of the University of Geneva (Switzerland) were randomly allocated to either direct or indirect bonding of a mandibular fixed retainer at the end of orthodontic treatment. Inclusion criteria included the presence of all mandibular incisors and canines; and the absence of active caries, restorations, fractures, or periodontal disease of these teeth. The patients were randomized in blocks of 4 using an online randomization service, with allocation concealment secured by contacting the sequence generator for assignment. Two and 5 years (T5) after bonding the retainers, the patients were recalled, and impressions were taken. The primary outcome was the 5-year survival of the mandibular fixed retainer bonded with both bonding methods. The secondary outcomes were the intercanine and interpremolar distances and the assessment of unexpected posttreatment changes (ie, changes in torque and/or rotations of the mandibular incisors and canines). Blinding was applicable for outcome assessment only. Kaplan-Meier curves were generated, and a Cox proportional hazard regression model was fitted for bonding type, age, and treatment. Linear mixed models were fitted to intercanine and interpremolar distances: bonding type, time, age, and treatment were modeled as outcomes. Sixty-four patients were randomized in a 1:1 ratio. At T5, 6 patients without previous failure were lost to follow-up from each group. At T5, the fixed retainer was debonded in 14 patients (54%) for each group. The hazard ratio of indirect bonding to direct bonding was 1.09 (95% confidence interval, 0.26-4.60; P= 0.91); there was no statistically significant difference in survival between the groups. Regarding intercanine and interpremolar distances, none of the tested prognostic factors reached statistical significance. Unexpected posttreatment changes were observed in 6 failure-free patients, all bonded with the direct bonding method. Only 1 patient required debonding of the fixed retainer. No other serious harms were observed. The 5-year survival rate for both direct and indirect bonding methods was 46%, without a statistically significant difference between bonding methods. Bonded retainers were effective in maintaining intercanine and interpremolar distances. Unexpected posttreatment changes were only observedwith retainers bonded with the direct bonding method. The trial was not registered. The protocol was not published before trial commencement. No funding or conflict of interest to be declared.

Impact of scanning strategy on the accuracy of complete-arch intraoral scans: a preliminary study on segmental scans and merge methods.

PURPOSEThis study investigated the accuracy of full-arch intraoral scans obtained by various scan strategies with the segmental scan and merge methods.MATERIALS AND METHODSSeventy intraoral scans (seven scans per group) were performed using 10 scan strategies that differed in the segmental scan (1, 2, or 3 segments) and the scanning motion (straight, zigzag, or combined). The three-dimensional (3D) geometric accuracy of scan images was evaluated by comparison with a reference image in an image analysis software program, in terms of the arch shape discrepancies. Measurement parameters were the intermolar distance, interpremolar distance, anteroposterior distance, and global surface deviation. One-way analysis of variance and Tukey honestly significance difference post hoc tests were carried out to compare differences among the scan strategy groups (α = .05).RESULTSThe linear discrepancy values of intraoral scans were not different among scan strategies performed with the single scan and segmental scan methods. In general, differences in the scan motion did not show different accuracies, except for the intermolar distance measured under the scan conditions of a 3-segmental scan and zigzag motion. The global surface deviations were not different among all scan strategies.CONCLUSIONThe segmental scan and merge methods using two scan parts appear to be reliable as an alternative to the single scan method for full-arch intraoral scans. When three segmental scans are involved, the accuracy of complete arch scan can be negatively affected.

Malocclusion and oral health-related quality of life among young Danish adults. Is there a difference between subjects who received orthodontic treatment during adolescence and subjects without treatment need? A cross-sectional study

Objectives To evaluate and compare malocclusion traits and oral health-related quality of life (OHRQoL) between untreated young adults assessed to have no orthodontic treatment need during childhood, and young adults treated orthodontically during childhood. In addition, to investigate the relationship between malocclusion and OHRQoL. Materials and methods One hundred undergraduate students were screened for eligibility. Subjects had intraoral scans and completed OHIP-14 questionnaires. Angle molar relationship, overjet, overbite, arch length and width, Little's Irregularity Index (LII), Peer Assessment Rating (PAR) index and Dental Aesthetic Index (DAI) scores were assessed. Unpaired t-tests were used to compare outcomes between treated and untreated subjects. Multiple regression analyses were conducted to model the relationship between OHIP-14 and several prognostics simultaneously. Results Ninety-six subjects were included (mean age ± SD = 23.7 ± 1.8 years): 41 treated and 55 untreated. The untreated subjects had significantly higher LII (p = .02), PAR (p = .01), DAI (p < .01) and overbite (p = .03). The treated subjects had significantly larger inter-canine and inter-premolar distances. No relationship was found between OHIP-14 and LII, PAR, DAI, age, gender and presence/absence of previous orthodontic treatment. However, the DAI score was significantly correlated with the OHIP-14 functional limitation domain. Conclusions Untreated subjects had significantly higher LII, PAR and DAI scores than the treated subjects. DAI score was significantly correlated with the OHIP-14 functional limitation domain.

Microimplant assisted rapid palatal expansion vs surgically assisted rapid palatal expansion for maxillary transverse discrepancy treatment

This study compared the skeletal and dental changes of microimplant assisted rapid palatal expansion (MARPE) with those produced by surgically assisted rapid maxillary expansion (SARPE) in postpeak adolescents and adults. The sample comprised 17 patients (mean age, 26±11years) selected for the MARPE group and 15 (mean age, 28.5±10.5years) selected for the SARPE group. Cone-beam computed tomography scans taken just before and after the expansion were used to assess dental and skeletal changes and compare the changes between the groups. MARPE showed greater transversal skeletal changes in the midface and posterior and anterior maxillary base measurements. The transverse displacement of the alveolar process was greater but not significant for the SARPE group than the MARPE group. Regarding dental effects, the root distance measurements did not differ between the groups, but SARPE produced a significantly greater increase in intermolar and interpremolar distance and a greater buccal inclination of the alveolar process and supporting teeth than MARPE. The MARPE technique showed an increase in skeletal transverse maxillary expansion at the midface and basal bone compared with SARPE, especially at the posterior palatal region; however, no difference was found in the expansion of the alveolar process between the 2 methods. MARPE presented a more parallel expansion in both a coronal and axial view, whereas SARPE led to a V-shaped opening. The greater buccal inclination of the alveolar process and supporting teeth was observed in the SARPE group.

Correlation between the transverse dimension of the maxilla, upper airway obstructive site, and OSA severity.

Acquiring a better comprehension of obstructive sleep apnea physiopathology can contribute to improving patient selection for surgical treatments. We hypothesize that maxillary transverse deficiency restricts the space available for the tongue, leading to upper airway obstruction during sleep. Our primary hypothesis was that maxillary transverse deficiency increases the prevalence of tongue collapse during drug-induced sleep endoscopy (DISE). The secondary hypothesis was that maxillary transverse deficiency will also increase the prevalence of circumferential collapse at the velopharynx. The exploratory hypothesis was that maxillary transverse deficiency is associated with increased obstructive sleep apnea severity. The objectives of this study were to correlate maxillary morphometric measurements with (1) the anatomic level of obstruction during DISE and (2) the apnea-hypopnea index on polysomnography. We made a cross-sectional analysis of patients with obstructive sleep apnea undergoing DISE in search of positive airway pressure alternative treatment. Maxillary measurements were collected from a computed tomography scan (interpremolar distance, intermolar distance [IMD] and sella-nasion A point angle), findings from DISE, and sleep study variables from polysomnography. Correlation between computed tomography, DISE, and polysomnography data was assessed using Pearson's correlation, and receiver operating characteristic curves were determined for each facial measurement. Sixty-nine patients were included in the study. The group with velopharyngeal circumferential collapse had mean IMD = 26.30 mm (25.5-31.45), and the group with anteroposterior collapse had mean IMD = 29.20 mm (26.8-33.10; P = .040). The group with complete tongue-base obstruction had mean interpremolar distance = 26.40 mm (25.1-28) and IMD = 26.30 mm (25.6-28.4), and the group without obstruction had mean interpremolar distance = 28.7 mm (27.2-30; P = .003) and IMD = 34.06 mm (32.1-37; P < .001). The receiver operating characteristic curve determined an IMD cutoff of 29.8 mm for predicting tongue-base obstruction. The maxillary transverse deficiency, identified by reduction in interpremolar distance and IMD, predicted the occurrence of complete tongue-base obstruction, complete concentric collapse at the velopharynx, and multilevel obstruction during DISE. We did not find an association between the maxillary measurements and obstructive sleep apnea severity. These associations hold some promise in ultimately supplanting insights previously available only through DISE.

Comparison of Mandibular Arch Expansion by the Schwartz Appliance Using Two Activation Protocols: A Preliminary Retrospective Clinical Study.

Background and objectives: Dental crowding is more pronounced in the mandible than in the maxilla. When exceeding a significant amount, the creation of new space is required. The mandibular expansion devices prove to be useful even if the increase in the lower arch perimeter seems to be just ascribed to the vestibular inclination of teeth. The aim of the study was to compare two activation protocols of the Schwartz appliance in terms of effectiveness, particularly with regard to how quickly crowding is solved and how smaller is the increasing of vestibular inclination of the mandibular molars. Materials and Methods: We compared two groups of patients treated with different activation’s protocols of the lower Schwartz appliance (Group 1 protocol consisted in turning the expansion screw half a turn twice every two weeks and replacing the device every four months; Group 2 was treated by using the classic activation protocol—1/4 turn every week, never replacing the device). The measurements of parameters such as intercanine distance (IC), interpremolar distance (IPM), intermolar distance (IM), arch perimeter(AP), curve of Wilson (COW), and crowding (CR) were made on dental casts at the beginning and at the end of the treatment. Results: A significant difference between protocol groups was observed in the variation of COWL between time 0 and time 1 with protocol 1 with protocol 1 subjects showing a smaller increase in the parameter than protocol 2 subjects. The same trend was observed also for COWR, but the difference between protocol groups was slightly smaller and the interaction protocol-by-time did not reach the statistical significance. Finally, treatment duration in protocol 1 was significantly lower than in protocol 2. Conclusion: The results of our study suggest that the new activation protocol would seem more effective as it allows to achieve the objective of the therapy more quickly, and likely leading to greater bodily expansion.

Lower Arch Dimensions in Children with Anterior Open Bite and Normal Vertical Overbite: A Cross-sectional Study.

Aim:Dental arch is a dynamic structure and its size depends on genetic and environmental factors. The aim of this study was to determine lower arch dimensions in children between 8 and 16 years with anterior open bite (AOB) and normal vertical overbite (NVO).Materials and Methods:A cross-sectional study was performed in 132 individuals with AOB and 132 with NVO between 8 and 16 years selected from public schools. Intercanine width, arch length, intermolar and interpremolar distances, and arch perimeter of the lower arch were measured in previously digitalized models using the GOM inspection program and an optical three-dimensional scanner.Results:Individuals with NVO presented smaller lower arch size with statistical differences in intercanine (P = 0.024, 95% confidence interval [CI]: 0.01, 0.02) and intermolar (P = 0.000, 95% CI: −1.76, −0.53) width and nonsignificant differences in the arch perimeter (P = 0.239, 95% CI: −1.57, 0.39) according to Mann–Whitney U-test.Conclusion:Individuals between 8 and 16 years of age with NVO showed smaller lower dental arch than individuals with AOB in most dimensions.

Comparison of Changes in Dental Arch Dimensions in Cases Treated with Conventional Appliances and Self-Ligating Damon System

Proposition: The objective of this study was to compare changes in maxillary and mandibular dental arch dimensions in cases treated nonextraction with conventional appliances and self-ligating Damon System. Materials and Methods: initial (T1) and final (T2) dental casts of 45 patients with Class I malocclusion treated nonextraction, with slight to moderate crowding, divided into two groups. Group 1: 21 patients treated with self-ligating Damon appliances, at a mean initial age of 18.37 years and mean treatment time of 2.11 years. Group 2: 24 patients treated with conventional appliances, at a mean initial age of 19.50 years and mean treatment time of 1.99 years. The model analysis was performed; Little irregularity index was used to evaluate crowding and arch form was evaluated by measurements in maxillary and mandibular arches including intercanine, interpremolar (first and second premolars) and intermolar distances and arch length. The intragroup comparison was performed with dependent t or Wilcoxon tests and intergroup comparison, with independent t or Mann Whitney tests. Results: In intergroup comparison of treatment changes (T2-T1) the Damon group presented an increase in maxillary transversal dimensions significantly greater than the conventional group. The change in maxillary arch length did not show difference between the groups. Regarding the mandibular arch, the Damon group presented a significantly greater increase in intercanine and inter first premolars than the conventional group. In The mandibular arch length, the greater and significant increase was observed in the groups of patients treated with conventional appliances. Conclusions: The treatment with the Damon appliances resulted in a significantly greater increase of maxillary arch dimensions when compared to conventional appliances. Mandibular intercanine and interpremolar distances also presented greater increase in Damon than conventional appliances. The increase in mandibular arch length was greater in conventional than in Damon group.

Indirect vs direct bonding of mandibular fixed retainers in orthodontic patients: Comparison of retainer failures and posttreatment stability. A 2-year follow-up of a single-center randomized controlled trial

The objectives of this 2-arm parallel trial were to compare the numbers of failures of mandibular fixed retainers bonded with indirect and direct methods and to investigate the posttreatment changes 2years after placement. Sixty-four consecutive patients from the postgraduate orthodontic clinic of the University of Geneva in Switzerland were randomly allocated to either an indirect or a traditional direct bonding procedure of a mandibular fixed retainer at the end of their orthodontic treatment (T0). Eligibility criteria were the presence of the 4 mandibular incisors and the 2 mandibular canines, and no active caries, restorations, fractures, or periodontal disease of these teeth. The patients were randomized in blocks of 4 (using an online randomization service) with allocation concealment secured by contacting the sequence generator for assignment. The patients were recalled 12months and 24months (T3) after retainer bonding. The main outcome was any first-time failure of retainers (ie, at least 1 composite pad debonded or fractured); unexpected posttreatment changes of the mandibular incisors and canines were a secondary outcome. Impressions and lateral cephalograms were taken at T0 and T3: changes in mandibular intercanine and interpremolar distances and mandibular incisor inclination were assessed. Blinding was applicable for outcome assessment only. The chi-square test and Cox regression were used to compare the survival rates of the retainers bonded with direct and indirect methods. Paired t tests were used to assess differences in intercanine and interpremolar distances and mandibular incisor inclination at T0 and T3. Significance was set at P<0.05. Sixty-four patients were randomized in a 1:1 ratio. One patient dropped out at baseline, and 3 patients did not reach the T3 recall. In 24 of 60 (40%) patients, the fixed retainer failed within 2years: 13 of 30 (43%) in the indirect bonding group and 11 of 30 (37%) in the direct bonding group (log-rank test, P=0.64). The hazard ratio was 1.26 (95% confidence interval, 0.56-2.81; P=0.58). Bond failures occurred mainly during the first year. There were no clinically significant changes in mandibular intercanine distance, interpremolar distance, and incisor inclination between T0 and T3, or between groups. In 5 patients (17%), all in the direct bonding group, unexpected posttreatment changes, systematically consisting in a lingual inclination of the mandibular left canine, were observed. In 1 patient (3%), the change was considered clinically severe. No other serious harm was observed. There was no difference in the risks of failure between mandibular retainers bonded with direct and indirect methods. Bonded retainers are effective in maintaining intercanine and interpremolar distances. There seem to be fewer unexpected posttreatment changes with retainers bonded with the indirect compared with the direct method. The trial was not registered. The protocol was not published before trial commencement. No funding or conflict of interest to be declared.

Comparison of transverse dental changes induced by the palatally applied Frog appliance and buccally applied Karad's integrated distalizing system.

ObjectiveTo compare the transverse dental changes induced by the palatally applied Frog appliance and buccally applied Karad's integrated distalizing system (KIDS).MethodsWe evaluated the pre- and post distalization orthodontic models of 39 patients, including 19 treated using the Frog appliance, which is palatally positioned (Frog group), and 20 treated using KIDS, which is buccally positioned (KIDS group). Changes in intermolar and interpremolar distances and the amount of maxillary premolar and molar rotation were evaluated on model photocopies. Wilcoxon and Mann-Whitney U tests were used for statistical evaluations. A p-value of < 0.05 was considered statistically significant.ResultsSignificant distopalatal rotation of premolars and distobuccal rotation of molars were observed in Frog group (p < 0.05), while significant distopalatal rotation of molars (p < 0.05), with no significant changes in premolars, was observed in KIDS group. The amount of second premolar and first molar rotation was significantly different between the two groups (p < 0.05 and p < 0.001, respectively). Furthermore, expansion in the region of the first molars and second premolars was significantly greater in KIDS group than in Frog group (p < 0.001 for both).ConclusionsOur results suggest that the type and amount of first molar rotation and expansion vary with the design of the distalization appliance used.

Cone-beam computed tomography evaluation of Pont's index predictability for Malay population in orthodontics.

Introduction:In orthodontic treatment, three-dimensional (3D) dental casts has a significant role in diagnosis and treatment planning. The aim of this study was to evaluate Pont's index predictability in orthodontics.Materials and Methods:Premolar arch width, molar arch width and mesiodistal width of the maxillary incisors were measured three-dimensionally to assess shape of dental arches. The data source was cone beam computed tomography (CBCT) high volumetric data acquisitions from Malay ethnic background. Arch widths were measured and recorded from 53 subjects (32 male and 21 female with the mean age, 25.81), both the maxillary and mandibular arches, to obtain CBCT high volumetric data. All measurements were obtained through CBCT Planmeca Romexis TM Software 2.3.1.R (Helsinki, Finland).Results:Pont's formula overestimated the upper and lower interpremolar distance, with mean differences of 8.35 ± 3 mm and 12.02 ± 3.20 mm, respectively. Furthermore, the formula overestimated the upper and lower intermolar distance, with mean differences of 7.87 ± 3 mm and 16.14 ± 5.86 mm, respectively.Conclusions:The results indicate that Pont's index is not practical for use with the Malaysian population since the index overestimated interpremolar and intermolar widths. This raises questions whether the index is a true predictor of arch width measurements.

Three-dimensional cephalometric superimposition of the nasomaxillary complex

Two-dimensional maxillary superimposition techniques have been routinely used in clinical practice, but a 3-dimensional plane has yet to be introduced and validated. The purposes of this study were to propose a new plane for regional superimposition of the maxillary complex and then to validate it through clinical data. Pretreatment and posttreatment palatal expansion records were used. The magnitudes of the transverse expansion at the levels of the first premolars and the first molars were assessed using the proposed superimposition plane and then were compared with the gold standard plaster model measurements. Descriptive statistics and agreement testing were performed to compare the methods. When comparing the superimposition and plaster measurement methods, the mean errors for intermolar and interpremolar distances were 0.57 and 0.59mm, respectively. Both the intraclass correlation coefficient and the Bland-Altman plot demonstrated high agreement between the 2 methods (intraclass correlation coefficient greater than 0.9). The proposed maxillary superimposition plane yields clinically suitable results when compared with the gold standard technique, with a mean error of less than 0.6mm for typical intra-arch measurements. This new landmark-derived maxillary plane for superimposition is a promising tool for evaluating maxillary dentoalveolar changes after treatment.