Mandibular Arch Width Research Articles

Association between Dental Arch Widths and Interarch Relationships in Children with Operated Unilateral Complete Cleft Lip and Palate

Palate and lip repair have great influence on the sagittal and transverse growth of the maxilla. The correlation between arch widths and sagittal interarch relationships in operated patients with complete unilateral cleft lip and palate (UCLP) in the mixed dentition is not clear. The aim of this study was to compare the maxillary arch widths of patients with UCLP and different interarch relationships (GOSLON Yardstick index). The study sample consisted of 144 pairs of dental casts of patients with complete UCLP from 8 to 10 years of age, from a single center. These dental casts were divided into three groups: group I (patients with GOSLON Yardstick 1 and 2 interarch relationships), group II (GOSLON Yardstick 3), and group III (GOSLON Yardstick 4 and 5). The control group consisted of 40 pairs of dental casts of noncleft Class I patients at the same age range. The maxillary and mandibular arch widths were measured at canine, deciduous molars, and permanent first molar regions. Intergroup comparisons were performed by analysis of variance followed by Tukey tests (P < .05). Maxillary arch widths were significantly smaller in all three groups with repaired UCLP compared to the control group. Group III showed reduced intercanine and second deciduous molar widths compared to group I. No intergroup differences were observed for mandibular arch widths. Operated UCLP patients with more severe sagittal discrepancies tend to show more severe transverse maxillary arch deficiencies.

Clinical importance of median mandibular flexure in oral rehabilitation: a review.

The mandible has a property to flex inwards around the mandibular symphysis with change in shape and decrease in mandibular arch width during opening and protrusion of the mandible. The mandibular deformation may range from a few micrometres to more than 1 mm. The movement occurs because of the contraction of lateral pterygoid muscles that pulls mandibular condyles medially and causes a sagittal movement of the posterior segments. This movement of mandible can have a profound influence on prognosis and treatment outcome for various restorative, endodontics, fixed, removable and implant-related prosthesis. The review unfolds the causes, importance and clinical implications of median mandibular flexure in oral rehabilitation. This review also highlights the appropriate preventive measures and techniques that should be adopted by clinicians to minimise the effect of flexural movement of the jaw during oral rehabilitation. This would not only help clinicians to achieve a good prosthesis with accurate fit and longevity but also maintain the health of the surrounding periodontal or periimplant gingival tissues and bone.

Comparison between rapid and mixed maxillary expansion through an assessment of arch changes on dental casts

BackgroundAim of this retrospective observational study was to compare upper and lower dental changes in patients treated with Rapid Maxillary Expansion (RME) and Mixed Maxillary Expansion (MME), assessed by dental cast analysis.MethodsTreatment groups consisted of 42 patients: the RME group (n = 21) consisted of 13 female and 8 male subjects with the mean age of 8.8 years ± 1.37 at T0 and 9.6 years ± 1.45 at T1; the MME group (n = 21) consisted of 12 female and 9 male patients with a mean age of 8.9 years ± 2.34 at T0 and 10.5 years ± 2.08 at T1. The upper and lower arch analysis was performed on four dental bilateral landmarks, on upper and lower casts; also upper and lower arch depths were measured. The groups were compared using independent sample t-test to estimate dental changes in upper and lower arches.ResultsBefore expansion treatment (T0), the groups were similar for all examined variables (p>0.05). In both RME and MME group, significant increments in all the variables for maxillary and mandibular arch widths were observed after treatment. No significant differences in maxillary and mandibular arch depths were observed at the end of treatment in both groups. An evaluation of the changes after RME and MME (T1) showed statistically significant differences in mandibular arch depth (p<0.001) and maxillary intercanine widths (p<0.05). Differences in maxillary arch depth and arch width measurements were not significant.ConclusionsRME and MME can be considered two effective treatment options to improve transverse arch dimensions and gain space in the dental arches. A greater lower arch expansion was observed in the MME group, which might be attributed to the “lip bumper effects” observed in the MME protocol.

A new approach to sex estimation using the mandibular canine index

Rao et al.'s mandibular canine index (MCI) is a simple odontometric method which uses the mandibular canine as the key to sex estimation. This index is defined as the ratio between the right canine mesiodistal dimension and the mandibular canine arch width. The aim of this study was to contribute to sex estimation using dental techniques by analysing the MCI efficiency, and to propose a new approach for its use. Measurements were taken from 120 plaster casts (70 females) in the 16-30 year age group. Although statistically significant sexual dimorphism was observed in both the mesiodistal dimension and the mandibular canine arch width, the MCI showed a low accuracy in sex classification (54.2% correct identifications). This accuracy was improved to 64.2% using receiver operating characteristics curve analysis. Yet, despite the better accuracy, these results reinforce the idea that the MCI may not be particularly useful in sex prediction, since it may not reflect the same degree of sexual dimorphism as its absolute measures.

Mandibular arch dimensions following bonded and banded rapid maxillary expansion

BackgroundThe purpose of this study was to examine changes in mandibular arch dimensions of subjects submitted to either bonded or banded maxillary expansion. MethodsThe sample comprised of two groups, one with patients who underwent maxillary expansion with banded, Haas-type expanders, retrospectively selected (banded group), and the other patients carefully matched in sex, age, and malocclusion, prospectively observed with bonded, Hyrax-type expanders (bonded group). Each group was composed of 29 subjects evaluated at T1, before maxillary expansion, and T2, after expansion and stabilization. The mandibular arches were evaluated for changes in arch width, depth, and perimeter. Paired and independent Student's t tests were used to compare groups. ResultsPatients in the banded group experienced significantly more mandibular arch width expansion in the molar region. Both groups experienced a decrease in arch depth; however, the bonded group showed significantly greater loss. ConclusionRapid maxillary expansion is an effective method for achieving a gain in arch width and space in the maxillary arch and, depending on the type of expander, banded or bonded, it produces a different response on an untreated mandibular arch.

Longitudinal evaluation of dental arch asymmetry in Class II subdivision malocclusion with 3-dimensional digital models

Class II subdivision malocclusions with their asymmetric occlusal relationships often pose treatment difficulties. The aim of this study was to evaluate the longitudinal changes of dental arch asymmetry in untreated subjects with Class II subdivision malocclusion. From 706 files from the University of Michigan Growth Study, longitudinal records of 17 untreated subjects with Class II subdivision malocclusion were included this study. Dental arch changes at 3 consecutive longitudinal intervals, defined by the cervical vertebral maturation method, were analyzed on digital dental models. The average ages of the subjects were 12.4, 15.1, and 19.1years at the 3 time periods, respectively. Maxillary and mandibular reference lines were constructed and used for the intra-arch asymmetry measurements. The Friedman test and analysis of variance with repeated measures were used to determine dental arch asymmetries at the P<0.05 level. All subjects were found to have a type 1 Class II subdivision malocclusion characterized by distal positioning of the mandibular first molar on the Class II side. No statistically significant intra-arch asymmetry changes were found for the maxillary and mandibular dental arches in any time period. Between the baseline and the final follow-up, the data indicated decreases in maxillary and mandibular intercanine arch widths and arch lengths symmetrically. The results of this study indicate that the dental arch asymmetry in patients with Class II subdivision malocclusions did not improve or worsen with growth.

Thirty-two-year follow-up study of Herbst therapy: A biometric dental cast analysis

The aim of this study was to analyze the very long-term effects of Herbst treatment on toothposition and occlusion. Fourteen patients from a sample of 22 with Class II Division 1 malocclusions consecutively treated with the banded Herbst appliance were reexamined 32 years after therapy. Dental casts were analyzed from before (T1) and after (T2) treatment, and at 6 years (T3) and 32 years (T4) after treatment. Minor changes in maxillary and mandibular dental arch perimeters and arch widths were seen during treatment (T1-T2) and posttreatment (T2-T4). Mandibular incisor irregularity remained, on average, unchanged from T1 to T2 but increased continuously during the 32-year follow-up period (T2-T4). Class II molar and canine relationships were normalized in most patients from T1 to T2. During the early posttreatment period (T2-T3), there was a minor relapse; during the late posttreatment period (T3-T4), molar and canine relationships remained, on average, unchanged. Overjet and overbite were reduced to normal values in all subjects during treatment (T1-T2). After treatment (T2-T4), overjet remained, on average, unchanged, but overbite increased insignificantly. Thirty-two years after Herbst therapy, overall, acceptable long-term results were seen. Stability was found in 64% of the patients for sagittal molar relationships, in 14% for sagittal canine relationships, in 86% for overjet, and in 86% for overbite. A Class II relapse seemed to be caused by an unstable interdigitation of the occluding teeth, a persisting oral habit, or an insufficient retention regimen after treatment. Most posttreatment changes occurred during the first 6 years after treatment. After the age of 20 years, only minor changes were noted. Long-term posttreatment changes in maxillary and mandibular dental arch perimeters and widths as well as in mandibular incisor irregularity seemed to be independent of treatment and a result of physiologic dentoskeletal changes throughout adulthood.

Accuracy of laser-scanned models compared to plaster models and cone-beam computed tomography

To compare the accuracy of measurements obtained from the three-dimensional (3D) laser scans to those taken from the cone-beam computed tomography (CBCT) scans and those obtained from plaster models. Eighteen different measurements, encompassing mesiodistal width of teeth and both maxillary and mandibular arch length and width, were selected using various landmarks. CBCT scans and plaster models were prepared from 60 patients. Plaster models were scanned using the Ortho Insight 3D laser scanner, and the selected landmarks were measured using its software. CBCT scans were imported and analyzed using the Avizo software, and the 26 landmarks corresponding to the selected measurements were located and recorded. The plaster models were also measured using a digital caliper. Descriptive statistics and intraclass correlation coefficient (ICC) were used to analyze the data. The ICC result showed that the values obtained by the three different methods were highly correlated in all measurements, all having correlations>0.808. When checking the differences between values and methods, the largest mean difference found was 0.59 mm±0.38 mm. In conclusion, plaster models, CBCT models, and laser-scanned models are three different diagnostic records, each with its own advantages and disadvantages. The present results showed that the laser-scanned models are highly accurate to plaster models and CBCT scans. This gives general clinicians an alternative to take into consideration the advantages of laser-scanned models over plaster models and CBCT reconstructions.

Alteration of Maxillary and Mandibular Growth of Adult Patients With Unoperated Isolated Cleft Palate

The objective of this study was to investigate the effects of cleft palate itself on the growth of maxilla and mandible. Fifty-two adult female patients with unoperated isolated cleft palate and 52 adult female individuals with normal occlusion were included in our study. Computer software was used for lateral cephalometry measurement. Manual measurement was performed for dental cast measurements, and sample t test analysis was applied to analyze the differences between the 2 groups using SPSS 17.0. The sella-nasion-subspinale point angle, subspinale-nasion-supramentale point angle, and maxillary arch length of the cleft group were significantly smaller than those of the control group (P < 0.01). Both maxillary and mandibular posterior dental arch widths of the cleft group were significantly larger compared with the control group (P < 0.01), whereas the sella-nasion-supramentale point angle, mandible arch length, palate height, and palate shelf inclination did not differ between the 2 groups. The measurements did not differ between the submucosal cleft and the overt cleft patients. Cleft palate itself has adverse effects on the maxilla growth with shorter maxillary arch length and wider posterior dental arch width.

Comparison of the mandibular arch widths in cleft palate patients

Mandibular arch widths and ratios are computed for unilateral cleft patients. The mandibular dental arch dimensions in unilateral cleft are different from that of the normals. Studies were made on the arch widths of normals of our population, but the arch dimensions of the cleft patients are not that widely studied. The mandibular dental arch dimensions in unilateral cleft are not different from that of the normals. The average MD33/MD44 and MD33/MD66 ratios among males and the normals showed a statistically significant difference (p<.05). The average MD33/MD44 ratio among females of the cleft and the normals also showed a statistically significant difference (p<.05). The parameters in the study did not show any statistically significant difference between the males and females among the cleft. There was significant difference between males of the cleft and the normal populations in (MD66). The long term stabilityof treatment results in cleft palate patients is to be taken up for further research

Sexual Diamorphism-An Odontometric Approach

Background: Teeth being the most stable tissue in the body provide one of the best records for forensic investigation. Tooth morphology is influenced by cultural, environmental and racial factors. Present study attempts to establish the applicability of human dentition in sexual dimorphism in Indian population. It focuses to measure the odontometric parameters (i.e. mandibular canine width, mandibular intercanine distance, incisor width, mandibular premolar and molar arch width,), calculate dental indices (i.e. mandibular canine index, mandibular premolar and molar indices) and thereby prove their efficacy in determining the sex of an individual. Materials and Methods: This cross sectional prospective study was carried out on 200 MBBS students of Kasturba Medical College, Mangalore. After taking written informed consent the intraoral odontometric parameters were measured and the data was then analysed using SPSS version, 11.5. Results: Results showed that mandibular canine width, mandibular canine index, mandibular premolar arch width, mandibular molar arch width, premolar index and molar index shows significant difference (p value<0.001) between males and females. Maximum sexual dimorphism exists in mandibular canine width (12.678) and mandibular canine index (12.639), while incisor width and intercanine distance have no applicability in sex identification. Maximum correlation is shown by mandibular canine width (0.657) and least by molar index (0.393). The predictive value of sexing a person is highest by using mandibular canine width alone (43.2%) and least by molar index(15.5%), this predictiblity increases considerably (56.4%) when all the parameters are combined together. Conclusion: Thus, the usefulness of dentition as an aid in gender determination by odontometric analysis is well supported. Mandibular teeth and in particular the mandibular canine can form the key in gender differentiation.

The relationship between mandibular arch length and widths in a sample of Yemeni subjects with normal dento-Skeletal relationship.

Objective:To assess the relationship between mandibular arch length and widths in a sample of Yemeni subjects aged (18-25) years.Materials and Methods:The investigation involved clinical examination of (765) adults; only 214 (101 females, 113 males) out of the total sample were selected to fulfill the criteria for the study sample (normal dento-skeletal relationship). Study models were constructed and evaluated to measure mandibular arch dimensions. The Spearman's correlation coefficient (r) was calculated between the measurements of arch widths and lengths.Results:Overall, the male group demonstrated greater transverse and sagittal mandibular dimensions; However, this was only statistically significant for measurements of inter-first and second molar distances and anterior arch length (P < 0.05). Relatively stronger linear relationships were observed between the inter-canine distance and mandibular arch lengths (P < 0.05, Spearman's r ranged between 0.17 to 0.50).Conclusion:Among studied mandibular dimensions in subjects with normal dento-skeletal relationship, only the inter-canine distance demonstrated a week to moderate linear relationship with the mandibular arch lengths.

Comparison of arch width, alveolar width and buccolingual inclination of teeth between Class II division 1 malocclusion and Class I occlusion

To compare the arch width, alveolar width, and buccolingual inclination of maxillary and mandibular posterior teeth between Class II division 1 malocclusion and Class I occlusion. Forty-five subjects with Class I occlusion and 45 subjects with Class II division 1 malocclusion were selected to measure the maxillary and mandibular arch width and alveolar width of premolars and first molars with digital caliper. Buccolingual inclination of maxillary and mandibular premolars and first molars were measured with a modified universal bevel protractor. All of the posterior teeth in both groups were lingually tilted. The maxillary premolars and first molars were significantly more lingually tilted (P < .05) in Class II division 1 malocclusion than in Class I occlusion. Mandibular first premolars were significantly less lingually tilted in Class II division 1 malocclusion than in Class I occlusion. No significant difference of buccolingual inclination was found in mandibular second premolars and first molars between the two groups. No significant difference in maxillary and mandibular arch width and alveolar width was found between the two groups. Buccolingual inclination rather than arch width and alveolar width plays an important role in transverse discrepancy of Class II division 1 malocclusion.

Short-term treatment effects of quad-helix on maxillomandibular expansion in patients with maxillary incisor crowding

The purpose of this study was to evaluate the effects of the maxillary arch expansion on maxillomandibular arch widths in patients treated with the quad-helix versus untreated controls. The treatment group consisted of 50 consecutive patients treated for maxillary incisor crowding with a quad-helix appliance in the early mixed dentition. Lateral cephalograms and dental casts taken at the start (T0) and end (T1) of the quad-helix treatment were obtained. The control group consisted of 50 untreated patients with the same type of malocclusion. Two consecutive lateral cephalograms and dental casts of each untreated patient were taken at about the same time as T0 and T1. All these study materials were analyzed for comparison between the two groups. The mean ages at T0 and T1 in the two groups were about the same. The maxillary first molars moved and tipped distally in the treatment group and mesially in the control group. The quad-helix treatment actually expanded the mandibular and maxillary arches concurrently. The more the maxillary arch widths were expanded and the less the maxillary first molars were inclined distally, the more the mandibular arch widths were expanded. The quad-helix activation caused lingual tipping and mesiobuccal rotation of the maxillary first molars. The mesiobuccal rotation of the maxillary first molars could turn molar occlusal relationships for the better from Class II to Class I. The quad-helix treatment gives rise to spontaneous expansion of the mandibular arch concurrent with maxillary expansion in the early mixed dentition patients with maxillary incisor crowding.

Changes in mandibular transversal arch dimensions after rapid maxillary expansion procedure assessed through cone-beam computed tomography

Objective: This study aimed at evaluating the changes in mandibular arch widths and buccolingual inclinations of mandibular posterior teeth after rapid maxillary expansion (RME). Methods: Baseline and post-expansion cone-beam computed tomographic (CBCT) images of patients who initially had bilateral posterior cross-bite and underwent RME with a banded-type expander were assessed in this study. The patients included 9 boys (mean age: 13.97 ± 1.17 years) and 11 girls (mean age: 13.53 ± 2.12 years). Images obtained 6 months after retention were available for 10 of these patients. Eighteen angular and 43 linear measurements were performed for the maxilla and mandible. The measurements were performed on frontally clipped images at the following time points; before expansion (T1), after expansion (T2), and after retention (T3). Statistical significance was assessed with paired sample t-test at p ＜ 0.05. Results: T1-T2 comparisons showed statistically significant post-RME increases for all measurements; similarly, T2-T1 and T3-T1 comparisons showed statistically significant changes. The maxillary linear and angular measurements showed decreases after expansion, and mandibular linear and angular measurements increased after retention. Conclusion: All mandibular arch widths increased and mandibular posterior teeth were uprighted after RME procedure.

Posterior crossbite in the deciduous dentition period, its relation with sucking habits, irregular orofacial functions, and otolaryngological findings

The aim of this study was to assess unilateral posterior crossbite, sucking habits, orofacial functions, and otolaryngological findings in the deciduous dentition. These findings would allow us to establish a preventive program for posterior crossbite, based on interceptive treatment at an early stage of dental development. We would determine the predictive value for posterior crossbite development in correlation with the duration of sucking habits. Data were collected on 30 children (13 boys, 17 girls) with unilateral posterior crossbite (mean age, 5.5 years; range, 3.6-7.2 years) and 30 children (17 boys, 13 girls) without crossbite (mean age, 5.9 years; range, 5.4-6.7 years), randomly selected from a local kindergarten. Information about each subject's nutritive and nonnutritive sucking behaviors was collected through parent interviews and questionnaires. An orthodontist and an otolaryngologist clinically examined all the children. Study models were obtained from all children, and dental arch parameters including arch widths in the canine and second deciduous molar regions were measured directly from the models. The data were then compared between the posterior crossbite and the noncrossbite groups. The results indicated correlations between prolonged pacifier sucking habit (P = 0.001), short frenulum linguae (P <0.001), smaller maxillary arch width (P <0.001), greater mandibular arch width (P <0.002), and unilateral posterior crossbite. A receiver operating characteristic curve was plotted for the pacifier sucking time. The borderline for the development of posterior crossbite suggested by the receiver operating characteristic curve was 18 months of pacifier sucking duration. The odds ratios between the crossbite and noncrossbite groups were 3.6 (CI = 0.97-13.4) for pacifier habit duration of 18 to 35 months and 21.9 (CI = 3.7-129.4) for pacifier suckers of more than 36 months. No significant correlation between enlarged adenoids and tonsils or impaired nasal breathing and the crossbite was found. These results suggest that the duration of a pacifier habit and a short frenulum linguae are associated with posterior crossbite at the age of 4 or 5 years because of the low tongue posture in the mouth. Pediatricians and pedodontists should give precise recommendations for enhancing breast feeding and discontinuing pacifier habits at least until the child is 18 months of age. Further studies are also needed to determine more objectively the etiology of tongue posture, swallowing pattern, and the length of the frenulum linguae in children with posterior crossbite.

A Comparative Study on Dental-Arch Morphology in Adult Unoperated and Operated Cleft Palate Patients

To investigate the effects of cleft itself and palatoplasty on the development of dental-arch morphology. Computed tomography scanning and imaging system for dental cast measurement were applied to statistically analyze the differences in dental-arch form among 30 adults with normal occlusion, 30 adult patients with operated unilateral complete cleft palate, and 30 adults with unoperated cleft palate. All maxillary arch widths and anterior arch length of the operated group are significantly smaller than those of the unoperated group (P < 0.01). In the unoperated group, the maxillary anterior arch width and maxillary and mandibular arch length are significantly smaller, whereas both maxillary and mandibular posterior arch widths are significantly larger as compared with the control group (P < 0.01). The influence of cleft palate on the development of maxillary arch is limited to the vicinity of the cleft in the anterior region only. Palatoplasty is the main cause resulting in the constriction of maxillary arch, while inhibiting the sagittal development of the anterior arch.

Maxillary and mandibular arch widths of Colombians

This study provides reference data and evaluates the potential of using regression models to predict maxillary and mandibular arch widths. A total of 473 Colombian mestizos, aged 5 to 17 years, with normal occlusions and malocclusions (Class I and Class II Division 1) were evaluated. Arch widths and tooth sizes were measured on each subject's dental casts. Anthropometric measurements of body size, facial breadth, and facial height were used, along with tooth sizes, to develop multiple regressions for predicting arch widths. Analyses showed that Class II subjects had significantly (P < 0.05) narrower anterior maxillary widths than those with normal occlusion or Class I malocclusion. Class I subjects had narrower interpremolar widths than those with normal occlusion or Class II malocclusion. Boys had significantly (P < 0.001) wider arches than girls, especially in the posterior aspects. Older children had significantly wider arches than younger children, with intermolar and interpremolar widths having the largest and smallest age effects, respectively. Regression analyses of subjects with normal occlusion showed that 2 to 5 variables combined to explain 36% to 64% of the variation in arch widths, with the sizes of the maxillary incisors and bigonial width explaining most of the variation. When applied to subjects with malocclusion, the predictions indicate transverse deficiencies in the premolar region of Class I subjects and deficiencies in the anterior maxilla of Class II subjects. Predictions based on Pont's index, the Schwarz analysis, or the McNamara rule of thumb were biased and less reliable than those based on the regressions.

Dental Arch Widths of Southern Chinese

To investigate the dental arch width of the Southern Chinese across buccal cusps, central fossae, or lingual cusps and compare these values with study findings in different populations and using different definitions. The dental arch dimensions of study casts of an unselected sample from a 12-year-old Hong Kong Oral Health Survey of 12-year-old children (n = 358; 210 boys and 148 girls) were measured. When compared with Caucasians, the Southern Chinese were characterized by a wider dental arch width. However, variations were great. All maxillary and mandibular male arch widths were significantly larger than female arch widths, except at the incisor regions. This study yielded a database about dental arch widths by which different studies on these widths can be compared.

上顎骨延長法と下顎正中分割を併用した下顎枝垂直骨切り術により治療を行った重度の骨格性ＩＩＩ級の１例

In this report, we describe the case of a 22-year-old male with severe skeletal Class III who was treated with distraction osteogenesis of the maxilla and intraoral vertical ramus osteotomy (IVRO). The severe skeletal Class III was accompanied by hypoplasia of the maxilla and overgrowth of the mandible (overjet, -20.0 mm; overbite, 1.0 mm). A high Le Fort I osteotomy was carried out, and the maxilla was distracted using the rigid external distraction II (RED II) system. After the active distraction and consolidation period, rigid fixation of the maxilla and IVRO were carried out; splitting of the mandible midline was added to the procedure to achieve a narrow mandibular arch width. After 6 months of postoperative orthodontic treatment, the occlusion and masticatory function of the patient had improved, and he was satisfied with the outcome of the treatment.