Intermolar Width Research Articles

Effects of Nasoalveolar Molding on Maxillary Arch Dimensions and Malocclusion Characteristics of Deciduous Dentition Patients with Cleft Lip and Palate.

To evaluate the effects of nasoalveolar molding (NAM) therapy on maxillary arch dimensions and malocclusion characteristics in patients with unilateral (UCLP) and bilateral cleft lip and palate (BCLP). Patients in deciduous dentition were referred to the institutional department of orthodontics. The NAM group consisted of 21 patients with UCLP (mean age 4.7±0.7 years) and 12 patients with BCLP (mean age 4.8±0.7 years). Sixteen patients with UCLP (mean age 4.9±0.9 years) and 5 patients with BCLP (mean age 5.4±1.1 years) were included in the non-NAM group. The plaster models of all patients were digitized. Dental arch dimensions and malocclusion characteristics were analyzed via digital software. One-way ANOVA with Bonferroni correction was used for statistical analysis. Intercanine and intermolar widths showed statistically significant differences according to the cleft type (P<.01). There was no statistically significant effect of NAM therapy on maxillary arch parameters and malocclusion characteristics (P>.05). The prevalence of anterior crossbite was 12.1% in the NAM group, and 23.8% in the non-NAM group. NAM therapy did not affect the maxillary arch dimensions and malocclusion characteristics in patients with UCLP and BCLP. The cleft type was the main factor, leading to a significant difference in maxillary widths.

Dimensional Accuracy of 3D-Printed, Digital and Conventional Stone Dental Cast of Dentate Patients Using Arch and Teeth Measurements

Aim: This study aimed to compare the conventional, digital, and three-dimensional (3D)-printed casts in terms of their accuracy in quantifying arch and teeth measurements. Materials and Methods: The conventional casts were prepared using polyether dental impressions. Digital impressions of the typodont reference casts were accomplished using an intra-oral scanner. The digital casts were first converted to stereolithography (STL) files which were then edited, and printed using an SLA printer and photo-polymer resin material. The measurements of the first two groups were completed using a digital caliper, while an imaging software was used to measure digital casts. The occlusocervial (OC) height and mesiodistal (MD) width of canines, second premolars (PMs), and molars of each jaw were measured. Additionally, intercanine width (ICW) and intermolar width (IMW) were also measured. Results: Overall, the lowest OC measurement errors were observed for 3D-printed casts for the upper canine, lower canine, and lower molar (0.003±0.01 mm). Similarly, the lowest MD measurement errors were observed for 3D-printed casts for upper canine, upper PM, and lower PM (0.002±0.01 mm). The ICW and IMW measurement errors for the 3D-printed casts were significantly lower (p &lt; 0.01) for the upper ICW (0.011±0.01 mm) and lower IMW (0.017±0.01 mm) than the other two groups. Compared to the conventional and digital casts, the lower ICW (0.013±0.01 mm) and upper IMW (0.017±0.01 mm) measurement errors observed for the 3D-printed casts were also lower, but non-significantly (p &gt; 0.01). Conclusions: 3D-printed casts presented the lowest OC, MD, ICW, and IMW measurement errors, than the conventional and digital casts. The highest measurement errors were associated with the digital casts.

The Effects of Fixed Versus Removable Orthodontic Retainers on Stability and Periodontal Health: 4-Year Follow-Up of a Randomized Controlled Trial.

Long-term or even indefinite retention is routinely prescribed after orthodontic treatment as a preventive safeguard against post-treatment changes induced by tooth movement, physiological healing, and the aging process. Though both fixed and removable versions of retainers may be equally effective in terms of results, sufficient research to support this assumption is missing at the moment. Long-term effects of fixed and removable retention on the periodontium, and the compliance level when used for an extended period of time. For 4 years participants were given a supply of canine-to-canine retainers and vacuum-formed canine-to-canine retainers. The inter-canine, as well as inter-molar widths, the length, and the extraction space opening of the mandibular anterior portion, were measured. Gingival inflammation, calculus, and plaque were observed, as well as the attachment of clinical and the case of bleeding during probing. 42 members had returned in the follow-up period, with 21 from each of the two groups. Measurements of the modified gingival index and plaque scoring were performed on the 10 intra-oral photographs that were taken at 4-week intervals in this study to investigate the intra-examiner reliability. After controlling for confounding variables, there was a 1.64 mm (95% confidence interval [CI], 0.30, 2.98 mm) median between-groups difference among patients who utilized vacuum-formed retainers (VFRs). The treatment groups did not vary in inter-canine and intermolar widths (P = 0.52; 95% CI, -1.07, 1.05), arch length (P = 0.99; 95% CI, -1.15, 1.14), or opening of extraction spaces (P = 0.84). A long-term study demonstrates that fixed retention can preserve the alignment of the mandibular anterior over time for the first time. Gingival discomfort and higher plaque scores were reported in both types of retainers.

EVALUATION OF MAXILLARY ARCH ANALYSIS IN MODINAGAR ADULTS WITH NORMO-OCCLUSION IN VIVO STUDY

Purpose: The aim of this study is to evaluatemaxillary arch analysis in Modinagar adultswith normo-occlusion. Materials and Methods: A total of 100 patients aged between 20 to 30 years with well-aligned arches up to second molar teeth were included in this study.Upper and lower alginate impression using properly fit dentulous metallic trays was taken for each arch. These impressions were transferred to the laboratory for pouring with Dental Stone to obtain dental arch. Each study model was signed by the coding number and either F or M letter (F=female, M=male).A digital calliper was used to measure the following parameters: Inter-molar distance, inter-canine distance, inter-molar depth and inter-canine depth. Results:The inter canine width among the males (36.70±2.589) was found to be significantly higher as compared to females (33.66±1.343). The inter-molar width among the males (55.07±4.726) was found to be significantly higher as compared to females (50.50±3.378). the intergroup comparison of inter-canine depth between males and females using the independent t test with p value less than 0.05 considered to be statistically significant.The inter-canine depth among the males (9.098±1.754) was found to be higher as compared to females (8.854±1.051) with p value of 0.041 denoting a significant difference. Among the males 54% were having ovoid arch form, 26% were having Tapered arch form and 20% were having Square arch form. Among the females 40% were having Ovoid arch form, 32% were having Tapered arch form and 28% were having Square arch form .The intergroup comparison between males and females in terms of shape of arch was statistically significant with p value of 0.346. Conclusion:This study shows that males showed larger arch size than females.The Ovoid arch form was the most prevalent, followed by the tapered and square arch form in the Modinagar population among both males and females.

Comparison of palatal depth and intermolar width in class I and class II div 1 malocclusion and in class II div 1 with hyperdivergent and hypodivergent pattern

: To compare the aligning efficiency, pain experienced by the patient during alignment and the post alignment third order values of anterior teeth in I arch (study) group and conventional NiTi (control) wire group.: A prospective clinical study.: A total of 40 dental arches (maxilla/mandible) were divided into 2 study groups with 20 dental arches (maxilla/mandible) in each group based on the selection criteria. Group I. Twenty dental arches (maxillary/mandibular) having 0.018” preadjusted appliance (MBT) brackets (ORMCO), aligned with I –arch 0.016”x0.014” copper NiTi wires. Group II Twenty dental arches (maxillary/mandibular) having 0.018” preadjusted appliance (MBT) brackets by ORMCO aligned with round super elastic NiTi archwires.: I -arch copper NiTi (study group) was more efficient in alignment compared to the superelastic NiTi (control group) in the lower arch and the values are statistically significant. There was torque expression in the I-arch group as compared to the superelastic NiTi group. The subjects in the I-arch (study group) experienced lesser pain compared to the superelastic NiTi (control group) and the pain values are statistically significant.

Evaluation of intercanine arch width, intermolar arch width and the canine fossa width in the determination of gender of an individual between 18 and 35 years – An in vitro analytical retrospective study

Objective s: The aim of this study is to verify and assess the usefulness of intercanine arch width, intermolar arch width, and canine fossa width in maxilla and intercanine and intermolar width in mandible for gender determination in the adult population. In medicolegal cases, estimation of gender using the skeletal remains of victims is imperative. The identity of an individual can be verified by examination of teeth and surrounding tissues from skeletal remains. Measurements from teeth and skull can help a Forensic Odontologist to identify deceased victims by age, gender, or race. The association of skeletal remains with gender gains utmost importance in cases of mass fatality such as earthquakes, tsunami, accidents, cyclones, and floods. If an individual is not in a condition to be identified, then they can be identified from the dentition or remains of dentition during any natural or manmade calamities. The benefit of determining gender in mass calamities is that accurately determined gender confines the number of missing individuals to one-half of the population in the majority cases. Many studies pertaining to maxillary arch widths have been performed yet the literature regarding mandibular arch widths remains scarce. Furthermore, in the literature, very few studies have been carried out to correlate canine fossa width and gender of an individual. Material and Methods: The study was carried out on a sample size of 120 study models, between 18 to and 35 years in department of orthodontics and dentofacial orthopedics and the samples had equal male and female distribution. A digital vernier caliper measured the intercanine arch width, intermolar arch width and canine fossa width and the parameters were measured by a single observer and statistical analysis was performed. Results: Intercanine arch width in maxillary arch was 36.38 ± 3.08 mm and 33.44 ± 2.72 mm for males and females correspondingly with P &lt; 0.001 which is statistically highly significant. Intermolar arch width in maxillary arch was 47.81 ± 3.02 mm and 45.2 ± 2.64 mm for males and females correspondingly with P &lt; 0.001 which is statistically highly significant. Canine fossa width in maxillary arch was 43.42 ± 2.58 mm and 40.36 ± 2.32 mm for males and females correspondingly with P &lt; 0.001 which is statistically highly significant. Intercanine arch width in mandibular arch was 27.43 ± 2.96 mm and 26.2 ± 1.97 mm for males and females correspondingly with P &lt; 0.05 which is statistically significant. Intermolar arch width in mandibular arch was 41.88 ± 3.47 mm and 39.89 ± 2.48 mm for males and females correspondingly with P &lt; 0.001 which is statistically highly significant. After employing the receiver operating curve, to figure out specificity and sensitivity of the parameters, high specificity of 97%, with the best sensitivity of 78% was recorded for the maxillary canine fossa width. Conclusion: The results show that in cases of mass calamities, maxillary canine fossa width will prove to be useful tool in gender determination accurately after analyzing the dental remains of young missing adults with multiple missing teeth. This will further aid the forensic odontologist to determine identity of the missing individual.

Analysis of maxillary arch expansion in growing patients treated with early Class III protocol versus RME.

To evaluate and compare the maxillary arch expansion obtained in growing patients treated with Class III early treatment protocol (the modified SEC III protocol), or rapid maxillary expansion (RME). This retrospective observational study included patients in the mixed dentition with maxillary constriction and/ or dental crowding. The first group consisted of 30 patients (11 males and 19 females, mean age 9.4 ±1.7 years) with dentoskeletal Class III malocclusion treated with the modified SEC III protocol. The second group of 30 patients (14 males and 16 females, mean age 9.3 ±1.5 years) with Class I or II malocclusion was treated with a Hyrax-type expander applied to bands on the first upper molars. For each subject, initial (T0) and post expansion (T1) digital dental casts were collected. The intermolar and intercanine widths, the arch lengths at both cusp and gingival levels, the anteroposterior length and the palatal depth were measured at T0 and T1. At T1 there were statistically significant differences for 3-3 occlusal (OC) (P < 0.009), arch-length OC (P <0.030), anteroposterior arch-length (AP) (P <0.003), Depth (P <0.030) and Ap (P <0.000). No statistically significant T0-T1 changes were found between the modified SEC III and Hyrax groups except for Depth (P <0.011) with a mean difference of 2.3 mm between the two groups. Both bonded and banded expanders, used in the modified SEC III protocol and RME treatment respectively, produced similar changes in the upper arch. The different initial dentoskeletal malocclusions of the two sample groups were not relevant to the post-expansion arch changes.

A retrospective study of the accuracy of Invisalign Progress Assessment with clear aligners

The objective of this study was to detective the accuracy of model superimposition and automatic analysis for upper and lower dentition width in Invisalign Progress Assessment during the process of clear aligners. 19 cases were included in this study. Pre-treatment dental cast (T0) and post-treatment dental cast after staged treatment (T1) were available for three-dimensional model superimposition. Subsequently, movements of maxillary teeth in the horizontal plane (cross-section) after staged treatment and width of upper and lower dentition were measured by three-dimensional model superimposition in the real world and Invisalign Progress Assessment separately. Consequently, the data collected from these two methods were compared. In Invisalign Progress Assessment, movements of maxillary teeth in the horizontal plane after staged treatment was 2.31 (1.59,3.22) [median (upper quartile, lower quartile)] millimeter (mm), while in three-dimensional model superimposition, the result was 1.79 (1.21,3.03) mm. The difference between the two groups is significant (P < 0.05). Intercanine width upper, intermolar width upper, intercanine width lower, and intermolar width lower were 36.55 ± 2.76 mm, 56.98 ± 2.62 mm, 28.16 ± 1.85 mm, 53.21 ± 2.72 mm separately in Invisalign Progress Assessment and were 36.48 ± 2.78 mm, 56.89 ± 2.58 mm, 28.05 ± 1.85 mm, 53.16 ± 2.64 mm separately in three-dimensional model analysis, which was no significant difference among these groups (P > 0.05). The data from Invisalign Progress Assessment was not in parallel with what was achieved from model superimposition with palate as a reference completely. The accuracy of model superimposition in Invisalign Progress Assessment needs further investigation, whereas the accuracy of model analysis in Invisalign Progress Assessment was accurate. Thereby, results from Invisalign Progress Assessment should be interpreted with caution by the orthodontist in the clinic.

Dental changes induced by a modified Herbst appliance followed by fixed appliances: A digital dental model analysis.

Herbst therapy is an effective treatment for Class II malocclusions. However, the maintenance of the effects after fixed appliances treatment remains questionable. This retrospective study aimed to assess, using digital dental models, the sagittal and transverse dental arch changes in young patients during two Class II Division 1 treatment phases, first with modified Herbst appliance (HA) and then with fixed appliances. The treated group (TG) comprised 32 patients (17 boys, 15 girls; mean age, 12.85 ± 1.16 years) treated with HA and fixed appliances. The control group comprised 28 patients (13 boys, 15 girls; mean age, 12.21 ± 1.35 years) with untreated Class II malocclusions. Digital models were obtained immediately before and after HA therapy and after fixed appliances. Data were statistically analyzed. Compared with the control group, the TG showed an increase in maxillary and mandibular arch perimeters and in intercanine and intermolar arch widths, a decrease in overjet and overbite, and an improvement in canine and molar relationships. In the time after HA therapy until the end of fixed appliances treatment, the TG showed a decrease in maxillary and mandibular arch perimeters, overjet, upper and lower intermolar widths; an increase in molar Class II relationship; and no changes in canine relationship, overbite, and upper and lower intercanine widths. In this sample of patients treated with HA, on average, there was an improvement in the Class II relationship, which seemed to remain after fixed appliances. The transverse dental changes achieved in HA phase relapsed after treatment with fixed appliances.

Scan Aided Dental Arch Width Prediction via Internationally Recognized Formulas and Indices in a Sample of Kurdish Population/Iraq.

Background: Numerous studies have investigated the applicability of Pont's index using a variety of selection criteria. The morphology of teeth and the shapes of the face are significantly influenced by racial, cultural, and environmental factors, so the current study focused on these demographics. Methods: This study is a retrospective study and included one hundred intraoral scanned images selected from patients seeking orthodontic treatment. Medit design software was used to obtain the real measurements and compare them to the predicted values from Pont's index. Paired t tests were used to test the validity of Pont's index, and regression equations were advocated to predict the inter-molar, inter-premolar, and anterior arch widths via SPSS version 25. Results: There were significant differences between the real anterior, inter-premolar, and inter-molar widths and the predicted values obtained from Pont's index, and there were weak positive correlations between the real values and the predicted values from Pont's index. Conclusions: Pont's index is not reliable to predict the arch widths for the Kurdish population, and new formulas are advocated. Hence, space analysis, malocclusion treatment, and arch expansion therapy should all take into account these results. Therefore, the derived equations may have further positive effects on diagnoses and treatment preparation.

Comparison of Efficiency of Bonded retainers and Vacuum formed retainers- A Randomized Clinical trial

Background: Major goal of orthodontic treatment is long term stability of the corrected teeth after orthodontic treatment. After orthodontic treatment there is always chance of relapse. To prevent relapse several appliances are available as a retention device such as bonded fixed retainers, vacuum formed retainers, removable Hawley retainer, Begg’s retainer. Now a days vacuum formed retainer has become more acceptable due to low cost, esthetic and easy fabrication. Objective: The purpose of this study was to analyze the clinical success of bonded retainers with vacuumformed retainers, as far as keeping up the consequences of orthodontic treatment in the lower arch as long as a year after debond. Methods: This was a randomized clinical trial (RCT) carried out at the department of Orthodontics, Bangabandhu Sheikh Mujib Medical University, Dhaka. In the study a total of 40 subjects who had fulfilled the selection criteria were randomly allocated to one of two groups, receiving either a vacuum-formed retainer or a bonded retainer for the mandibular arch. Qualification criteria was patients approaching debond after treatment with preadjusted edgewise fixed orthodontic appliance whose pretreatment records and study models were accessible to confirm pretreatment labial segment crowding or spacing and who had clinically acceptable alignment after treatment. The principle purpose was to research the clinical adequacy of the 2 kinds of retainers regarding changes in incisor irregularity at one year of preservation of treatment outcome. The following measurements were documented at each time point (6 and 12 months) with a digital caliper: Little’s irregularity index, intercanine width, intermolar width, arch length, extraction space opening. Result: The two groups were very much coordinated as for age, sex, clinical qualities, and treatment plans. Four patients did not attend in the follow up period and the study finished up in 36 patients. There was a statistically significant difference between the groups for changes in Little’s irregularity index and arch length. Vacuum-formed retainer group showed greater changes than the bonded retainer group (P value 0.035 and 0.022). There were also no statistically significant changes at any time for intercanine width and intermolar width. Conclusion: Some relapse is likely after fixed orthodontic treatment regardless of retainer choice, and this is negligible in many patients after debond. Bonded retainers have a superior capacity to hold the mandibular incisor arrangement after orthodontic treatment than vacuum-formed retainers. Trial registration: not done. Bangladesh Medical Res Counc Bull 2022; 48: 105-111

Comparison of alignment efficacy and arch dimensions changes with superelastic-, heat-activated-, and seven stranded coaxial nickel-titanium archwires during fixed orthodontic treatment – A double-blind randomized clinical trial

Objectives: The objectives of this study were to compare the alignment efficacy, changes in arch dimensions, and pain experience with three different nickel-titanium (NiTi) archwires. Material and Methods: Forty-five subjects were subjected to indirect bonding in the mandibular arch, and allocated to three groups using block randomization; Group 1 (0.014” Superelastic NiTi), Group 2 (0.014” 27° Copper NiTi), and Group 3 (0.016” seven stranded coaxial NiTi archwire). The mandibular study models were retrieved periodically at 4-week intervals for 12 weeks, which were blinded to measure the change in Little’s irregularity index (LII) and dental arch dimensions. Pain and discomfort were recorded with visual analog scale at five different time intervals, namely, immediately after bonding (0) and at 1-, 4-, 8-, and 12-h for initial 7 days. Repeated analysis of variance, Wilcoxon Signed-Rank test, post hoc Bonferroni test, and Friedman’s test was applied for the comparison and was used for data analysis. Results: A significant reduction of LII score and increase inarch length, intercanine, interpremolar, and intermolar width (P ≤ 0.001) were observed after 12 weeks among all groups. However, intergroup comparison showed significant mean changes only for intercanine width (Group 1 versus 3) and interpremolar width (Groups 1 and 3; Groups 2 and 3). All other variables were found to be insignificant at all-time intervals when compared among each group. The increase in pain score was maximum with Group 1and least with Group 3. Conclusion: All archwires were found to be effective in reducing the LII score. Nevertheless, Group 3 archwire could achieve reduction of LII to zero in 14% of subjects than Groups 1 and 2.

Three-dimensional relationship between the degree of bilateral impacted mandibular third molars angulation and the mandibular dental arch parameters: a cross-sectional comparative study.

The purpose of this study was to three-dimensionally evaluate the relationship between the degree of bilateral impacted mandibular third molar (IM3M) angulation and the mandibular dental arch parameters in normal skeletal and dental malocclusion patients. In this retrospective cross-sectional comparative study, 120 adult subjects' cone-beam computed tomography (CBCT) images were three-dimensionally analyzed. The sample included 120 adults aged 20-30years, with a gender distribution of 51 male and 69 female participants. The sample was divided into 100 adults with bilateral IM3M (study group) and 20 adults with normal bilateral erupted M3M (control group). The study group was sub-divided into three groups according to the degree of IM3M buccolingual angulation (BL°): group A, < 12° on the center of the ridge (N = 30), group B, 12-24° off-center of the ridge (N = 40), group C, > 24° off-center of the ridge (N = 30). The study group was also sub-divided into two groups according to IM3M mesiodistal angulation (MD°): group 1 from 10 to 45° (N = 36), group 2 > 45° (N = 64). Comparison within and between groups was performed using one-way ANOVA followed by Tukey's post hoc test. The correlation between IM3M, BL, and MD angulation and the mandibular arch parameter was calculated using Pearson's correlation coefficient. Statistically significant differences (P < 0.001) were found between the IM3M BL° and anterior teeth inclination, arch length (AL), and inter-second molar width (inter 2nd MW) as well as between the IM3M MD° with anterior crowding and the arch length (P < 0.001). A significant positive correlation was found between IM3M BL° and anterior teeth inclination and between IM3M MD° and anterior teeth crowding and inter 2nd MW. A significant negative correlation was observed between IM3M BL° and inter 1st MW and 2nd MW. The degree of buccolingual and mesiodistal angulation of the impacted mandibular third molars was related with mandibular dentoalveolar changes. Increased buccolingual angulation is generally associated with increased anterior teeth inclination and decreased 1st and 2nd inter-molar width. The increase in mesiodistal angulations was generally related with increased anterior teeth crowding and 2nd inter-molar width. Assessment of the relationship between the impacted mandibular third molars and the degree of arch discrepancy, and the position of mandibular incisors in the three planes of space might help in the decision-making process for the extraction of the impacted third molars in adult patients.

Assessment of Dental Crowding Occurring in Mixed Dentition in Maxillary and Mandibular Arches Based on Tooth Size-Arch Length Relationships and Certain Cephalometric Parameters.

The aim of the study is to find indicators of crowding in primary and mixed dentition that may lead to occurrence of dental crowding in future dentition using dental measurements. A sample of 300 children was selected and divided into two groups based on their age primary dentition and mixed dentition. Dental arch impressions were made and casts were poured. The study was then divided into two phases for assessment of degree of crowding by Little's irregularity index (LII) and by measurement of tooth size-arch length discrepancies. Appropriate statistical analysis was used to assess the correlation of measurements in crowded and noncrowded groups. It was found that Little's index is less dependable as an indicator of anterior crowding. In the primary dentition, there is significant difference in inter-canine width between lower noncrowded and crowded dentition. In the mixed dentition, there is significant difference in Intermolar width between upper noncrowded and crowded dentition and in sum of incisors between noncrowded and crowded dentition in both the arches. Little's index is not a reliable indicator of crowding in both primary and mixed dentition. Inter-canine width of lower arch can be considered as an indicator of crowding in primary dentition. The intermolar width of upper arch, sum of incisors in upper and lower arch and the intercanine width of upper and lower arch can be considered indicators of crowding in the mixed dentition. Kandakkeel FN, Nagar P, Saseendran A, et al. Assessment of Dental Crowding occurring in Mixed Dentition in Maxillary and Mandibular Arches based on Tooth Size-Arch Length Relationships and Certain Cephalometric Parameters. Int J Clin Pediatr Dent 2023;16(2):357-362.

Long-term effects of orthodontic interceptive expansion treatment : Aretrospective study.

The aim of this retrospective cohort study was to evaluate the long-term effects of interceptive orthodontic treatment with aremovable expansion plate, based on transversal, sagittal, and vertical parameters. Atotal of 90patients needing interceptive treatment due to acrossbite or space deficiency were included. Records consisting of clinical photos, radiographs, and digital dental casts were collected for evaluation at two time points: the start of interceptive treatment (T0) and the start of comprehensive treatment (T1). Molar occlusion, overjet, overbite, presence and type of crossbite, mandibular shift, and transversal measurements were recorded for comparison. After expansion with removable appliances, asignificant increase in intermolar width was achieved and could be maintained over the observation period (p < 0.001). However, no significant changes regarding overjet, overbite, or molar sagittal occlusion were observed. Crossbite correction was successful in 86.9% of patients with unilateral crossbite and in 75.0% of patients with bilateral crossbite (p < 0.001). Early expansion with aremovable expansion plate is asuccessful method to correct crossbites and increase intermolar width in the early mixed dentition phase. Results remain stable until the start of comprehensive treatment in the permanent dentition.

Maxillary and Mandibular Interarch Width Among Different Malocclusions

Objective: To determine the association of maxillary and mandibular interarch width among different malocclusions. Material and Methods: This cross-sectional study was done at the Department of Orthodontics of the Dr. Ishrat Ul Ibad Khan Institute of Oral Health Sciences, Dow University of Health Sciences, Karachi, during a period of one year from January 2017 to December 2017. Individuals with a Class I canine and molar relationship with minor crowding, normal growth and development, and mal-aligned upper and lower dental arches. Class II molar and canine relationship on at least one side, Class II division 1 or 2 groups, bilateral Class III molar relationship in centric occlusion, Class III permanent canine relationship with excessive negative overjet, good facial symmetry, and participants had to have all their permanent teeth present except for their third molars were included. Readings were obtained by measuring the interarch width using a vernier gauge caliper. The calibration of the vernier caliper was checked daily using the standard technique. The intercanine arch width was measured from the cusp tip of one canine to the contralateral canine. Intermolar width was assessed as the distance between the central fossae of the left and right first molars. The readings were taken by a single examiner, and the measurement was repeated three times with an interval of two minutes between each measurement to reduce the possibility of errors. To assess the reliability of the measurements, the intra-examiner reliability was determined using the intraclass correlation coefficient (ICC). The collected data was analyzed using statistical software, SPSS version 26. Results: The study examined the maxillary and mandibular interarch widths of participants with different types of malocclusions. Class I had the highest maxillary intercanine width, and Class III had the highest maxillary intermolar width. Class III had the highest mandibular intercanine and intermolar width. Class II Division 2 had the lowest intercanine and intermolar width in both arches. Significant differences were observed in the mean intermolar width in the mandibular arch between Class II Division 2 and Class III malocclusions and in the maxillary intercanine width between Class I and Class II Division 2 malocclusions. No significant difference was found in other width measurements among the different types of malocclusions. Conclusion: It has been concluded that patients with Class III malocclusion had narrower upper width measurements compared to the normal occlusion sample. Keywords: Maxillary, mandibular, interarch width, malocclusion

Dimensional changes in the palate associated with Invisalign First System: a pilot study.

To compare palatal dimensions and molar inclinations after Invisalign First System (IFS) to those in patients treated with slow maxillary expansion (SME) and normal controls. Twenty-three mixed dentition patients treated with IFS were gender- and dental age-matched to another two groups: Haas-type SME and control group. The intercanine width (ICW), intermolar width (IMW), palatal surface area (SA), volume (V), and first molar buccolingual inclinations (MI) were measured before (T1) and after (T2) treatment. Analysis of variance was used to compare the differences among the three groups. The ICW increased significantly by 3.10 mm after IFS, 4.77 mm with SME, and 0.54 mm in controls; the difference among the groups was statistically significant (P < .001). The IMW increased by 1.95 mm in IFS, 4.76 mm in SME, and 0.54 mm in controls, with significant intra- and intergroup differences. Palatal SA and volume increased by 43.50 mm2 and 294.85 mm3 in the IFS group, which differed significantly from SME, but was similar to controls. The right and left MI increased 0.24° and 0.08° buccally, respectively, in the IFS group, which was comparable to controls, while significantly increased buccal MI was observed in the SME group. IFS expands the upper arch with increased ICW and IMW compared to controls, but the expansion amount is smaller than SME. Unlike SME, IFS has no effects on palatal dimensions and molar inclinations.

The Reliability of ClinCheck® Accuracy before and after Invisalign® Treatment—A Multicenter Retrospective Study

The objective was to evaluate the accuracy of ClinCheck® reliability in the sagittal, vertical, transverse, and arch length dimensions before and after Invisalign® (Align Technology, Santa Clara, CA, USA) treatment. This retrospective study was conducted on 206 patients who underwent dual-arch clear aligner therapy exclusively with Invisalign®. Digital models were obtained from iTero® scanners from three different private practices where the treatment plans were performed and executed by multiple orthodontists with varying degrees of experience. The ClinCheck® models of the initial, achieved, and predicted outcome were obtained from Align Technology® and the values were compared using Pearson correlation (p &lt; 0.05) to determine if predicted values were correlated with achieved values. ANOVA was used to compare the different centers. The highest reliabilities were associated with interincisal angle (96.23%), upper intercanine width (97.97%), lower intercanine width (97.67%), upper intermolar width (97.58%), and lower intermolar width (97.72%) (p &lt; 0.001). The lowest reliabilities were associated with arch length parameters in which the upper was 38.79% and the lower at 30.02% (p = 0.03, p &lt; 0.001). However, there were no statistically significant differences between the centers in terms of the accuracy of treatment provided. The mean predicted accuracy of Invisalign® was 76.85% overall; however, Invisalign® providers may need to exaggerate the digital tooth movements to achieve the desired outcome.

Gender Determination in Pakhtun Pakistani Population Using Dental Arch Dimensions: A Digital Model Study

Introduction: In circumstances where the ante mortem list is unknown, gender determination would exclude one-half of the population, aid in a more precise search of the ante mortem records. This study aims to formulate gender prediction models in the Pakhtun Pakistani population using digital dental arch dimensions. Methods: Data collection and analysis of the dental casts were conducted on 128 subjects, 64 males and 64 females from the Pakistani population. The mean age of the subjects was 19.2 years old. Several linear dental arch dimensions were measured and recorded for both upper and lower arches. Results: It was found that gender differences in linear arch dimensions were statistically significant for both males and females (p&lt;0.05); in which the arch dimensions for the males were larger than the arch dimensions for the females. Stepwise discriminant function analysis found that the highest discriminant power of the variables was present within the inter-second premolar width for the upper arch and inter-molar width for the lower arch. These variables significantly contributed to gender variance. Moreover, the prediction of 67.2% of original grouped cases for the upper arch and 66.4% of cross-validated group cases was correct. Similarly, the correct prediction was made on 64.8% of original grouped cases for the lower arch and 64.1% of cross-validated group cases. Conclusion: The dental arch dimensions were larger among the males compared to the females. Prediction models obtained in this study were moderately strong predictors which may be used as an adjunct to predict gender.

Three-dimensional relationships between condylar volume and dentoskeletal characteristics in Class II hyperdivergent female adults

BackgroundThis study aimed to determine the differences among various volumes of condylar osseous patterns and the corresponding dentoskeletal characteristics based on the risk of temporomandibular disorder.MethodsCraniofacial spiral computed tomography data of 60 Class II hyperdivergent female adults were divided into normal, resorptive, flattened, and osteophyte groups based on condylar osseous forms. The condylar volumes of each group were compared, and their correlations with the dentoskeletal characteristics were assessed in three dimensions. Pairwise least significant difference tests were used to examine individual pairwise differences between groups, and one-way analysis of variance was used to measure differences among multiple groups. Pearson correlation and Spearman rank correlation analyses were used to determine the correlation between condylar volume and dentofacial characteristics. Statistical significance was established at p < 0.05.ResultsThe condylar volume in the normal group was significantly greater than that in the changed groups, with no significant differences between the subgroups. The decrease in condylar volume was associated with a retruded and clockwise-rotated mandible with shorter rami. Condylar volume was negatively correlated with overjet, the alveolar height of the lower anterior and posterior teeth, sagittal inclinations of the lower teeth, intermolar width of the mandibular first molars, and width between the corresponding alveolar crests.ConclusionMultiple three-dimensional dentoskeletal characteristics of Class II hyperdivergent female adults are correlated with condylar bony changes, regardless of the form. These results could be helpful in indicating potential pathological changes in the temporomandibular joint and in making proper treatment plans for these patients.