Morphological evaluation of maxillary arch in unilateral buccally and palatally impacted canines: a cone-beam computed tomography (CBCT)-based study in Northern Iran.

Purpose: This study investigated the association between the maxillary impacted canines' position and the maxilla's morphological features in an Iranian population based on cone-beam computed tomography (CBCT) images. Material and methods: In this cross-sectional descriptive-analytical study, 47 CBCT images of unilateral buccally impacted maxillary canines and 47 CBCT images of unilateral palatally impacted maxillary canines were examined. Several morphological variables were compared between the impacted and non-impacted sides, and between the buccal and palatal impaction types. Results: Gender and age were not significantly associated with the canine impaction type. The alveolar bone height at the impacted side was significantly greater in the buccally impacted group than in the palatally impacted group (p = 0.016). In a comparison of the impacted and non-impacted sides, all variables of alveolar bone thickness at depth of 2 mm, maxillary arch width, and palatal volume had significantly smaller values in the impacted side in both buccally and palatally impacted groups (p < 0.05). The alveolar bone was significantly thicker at the depth of 10 mm in the impacted side of the buccal group (p = 0.024). The maxillary arch perimeter was significantly smaller in the impacted side of the buccal group (p = 0.008). The palatal depth did not significantly differ between the groups. Conclusion: Among the studied variables, the alveolar bone thickness showed contrary results at different depths. The palatal volume and maxillary arch width were significantly smaller on the impacted side in both buccal and palatal groups, and the arch perimeter showed the same results only in the buccal group.

Correlation of mandibular third molar orientation and available retromolar space with arch length discrepancy in subjects with different growth pattern.

Aim and Objective: To evaluate, compare, and correlate the mandibular third molar orientation and available retromolar space with arch length discrepancy in subjects with skeletal class II malocclusion and different growth pattern. Material and Method: A total of 250 patients (age >18 yrs) having skeletal class II malocclusion (based on YEN angle and WITS appraisal) were divided into two groups. Both the groups (Group I with erupted mandibular third molars {N = 150} and Group II with impacted mandibular third molars {N = 100}) were subdivided into subgroups IA (n = 71), IB (n = 19), IC (n = 71) and Group IIA (n = 54), IIB (n = 30) and IIC (n = 16) for normo-, hypo- and hyperdivergent growth patterns, respectively (based on Jarabak ratio and Sn-Go-Gn angle). Four parameters, that is, retromolar space, width of third molar, third molar angulation, and mandibular incisor angulation were measured on orthopantomogram whereas arch length discrepancy was calculated with the help of lateral cephalogram and study model. Intragroup, intergroup comparisons (using unpaired Student's 't' test), and Pearson's correlation coefficient for assessed parameters were obtained. Result: Third molar angulation and retromolar space were significantly higher in Group I than in Group II (hyperdivergent pattern of Group II had highest value). The width of third molar was less than retromolar space in Group II and vice versa for Group I. Mandibular incisor angulation and arch length discrepancy were more in Group II than in Group I, but difference was statistically nonsignificant. Strong positive correlation was observed for mandibular third molar angulation and available retromolar space in normo- and hyperdivergent growth patterns. Conclusion: Lack of retromolar space along with increased amount of arch length discrepancy and mandibular incisor angulation is responsible for increased chances of third molar impaction in some subjects with class II malocclusion.

Trueness of intraoral scanning for different tooth-size arch-length deficiencies.

Background/purpose: As science and technology continue to advance, the utilization of intraoral scanners (IOSs) has become increasingly popular in the orthodontic workflow. The aim of this study was to discuss whether the degree of crowded arches affects scan accuracy. Materials and methods: Three different crowding levels of dental models (model MI: mild, model MO: moderate, and model SE: severe) were scanned using both an IOS and desktop scanner. Stereolithographic files were obtained and superimposed via CAD software to calculate differences between each measuring point of a model and the farthest corresponding point. The deviations from three models were compared with statistical analysis. Results: The trueness of different crowding arches showed that the deviation value of model SE was the maximum, followed by model MI, and model MO in the maxillary arch. In the mandibular arch, the order of the deviation from greatest to least was firstly model SE, then model MO, and model MI. Significant differences were observed among the maxillary models (P < 0.001), but there was no significant difference between models in the mandible (P = 0.669). Conclusion: The trueness of the three crowded arches is in the clinically acceptable range. The degree of crowding increases, the trueness of scanning at each position decreases. In the maxillary arch, more severe crowding corresponds to higher deviations. In the mandible, the degree of crowding is not explicitly related to the maximum deviation; therefore, the clinician should notice the deviation when using IOSs for crowding cases.

Reliability of mixed dentition space analysis using a digital model obtained from an optical impression: a preliminary study.

OBJECTIVE: While mixed dentition space analysis is a common practice in pediatric dentistry, digital models created using an intraoral scanner are not as widely used in clinical settings. This preliminary study used a very small sample size with one reference model and aimed to (1) compare the accuracy of mixed dentition space analysis using a digital model obtained from an optical impression with that of conventional plaster model-based analysis and (2) assess inter-examiner differences. RESULTS: The space required for the mandibular permanent canine and premolars and arch length discrepancy were calculated using each model. The largest significant difference between plaster- and digital model-based analyses was identified when the right arch length discrepancy was considered (-0.49 mm; 95% confidence interval: -0.95-0.03); however, the value was considered clinically insignificant. Significant inter-examiner differences were observed for six items of the plaster model; however, no such differences were observed when using the digital model. In conclusion, digital model space analysis may have the same level of accuracy as conventional plaster model analysis and likely results in smaller inter-examiner differences than plaster model analysis.

Validation of a mathematical-geometrical model to calculate the length of an individual anterior arch.

PURPOSE: For resolving anterior dental crowding or spacing, it is of key interest in personalised orthodontic diagnostics and treatment planning to predict the extent of space gained or lost in the anterior dental arch by changing incisor inclination or position. To facilitate the determination of anterior arch length (AL) and to predict its alterations following tooth movements, a mathematical-geometrical model, based on a third-degree parabola, was established. The aim of this study was to validate this model and assess its diagnostic precision. METHODS: This retrospective diagnostic study evaluated 50 randomly chosen dental casts taken before (T0) and after (T1) orthodontic treatment with fixed appliances. Plaster models were digitally photographed, allowing two-dimensional digital measurements of arch width, depth and length. A computer programme based on the mathematical-geometrical model to be validated was created to calculate AL for any given arch width and depth. Mean differences and correlation coefficients as well as Bland-Altman plots were used to compare the measured and the calculated (predicted) AL, evaluating the precision of the model. RESULTS: Inter- and intrarater reliability tests showed reliable measurements of arch width, depth and length. Measured and calculated (predicted) AL revealed high concordance according to concordance correlation coefficient (CCC), intraclass correlation coefficient (ICC), and Bland-Altman analyses and negligible differences between the mean values. CONCLUSIONS: The mathematical-geometrical model calculated anterior AL without significant difference to the measured AL, indicating its validity. The model can thus be used clinically for predicting alterations of AL following therapeutic changes of incisor inclination/position.

What are the intra-arch risk factors for palatally displaced maxillary canine? - Results of a case-control study.

INTRODUCTION: This study aimed to identify the intra-arch risk factors for palatally displaced canine by comparing the maxillary transverse dimensions, palatal depth (PD), and arch length (AL) of the subjects with and without impacted canine using cone-beam computed tomography (CBCT). METHODS: In this prospective case-control study, 79 CBCT images of gender- and skeletal feature-matched subjects (25 cases and 54 controls) were compared. Based on the CBCT images, maxillary transverse widths at four levels (molar basal, molar alveolar, premolar basal, and premolar alveolar), maxillary PD, and maxillary AL were measured. Group comparisons were assessed using analysis of variance (ANOVA), followed by post-hoc Scheffe's test, and risk factors were identified using univariate and multivariate logistic regression. RESULTS: The impacted canine group showed significantly smaller molar alveolar width, premolar alveolar width, PD, and greater AL compared to the control group (P = 0.046, P < 0.001, P = 0.003, and P = 0.001, respectively). No significant difference was observed in the molar and premolar basal width measurements between the two groups. Multivariate analysis showed that impacted maxillary canine was influenced by premolar alveolar width (odds ratio (OR): 0.669), PD (OR: 0.532), and AL (OR: 1.739). CONCLUSION: Intra-arch risk factors, such as reduced maxillary premolar transverse alveolar width, PD, and greater AL, are associated with palatally displaced canine.

Evaluation of the impact of reference tooth morphology and alignment on model measurement accuracy.

Background: The development of personalized and high-precision dental treatment is inseparable from the accurate measurement and analysis of the model. Compared with traditional plaster models, digital models allow dentists to obtain richer and more detailed inspection results. However, the measurement of digital models in clinical practice usually ignores the influence of the overall three-dimensional (3D) structure of teeth and tooth arrangement on the measurement results. The purpose of this study was to evaluate the effect of calibrated tooth axis and tooth arrangement on tooth width and arch length. Methods: A total of 110 digital models from 80 participants were used to measure teeth width and dental arch length using the following methods: Method A, simple positioning of the proximal and distal of teeth; Method B: calibration of the clinical crown axis; and Method C: calibration of the overall 3D axis of the teeth. The Measurand model included pre- and post-orthodontic models of the same patients to assess the impact of tooth alignment on outcomes. Results: In the aligned dentition, whether the tooth axis was calibrated had no effect on the measurement results. On unaligned dentitions, calibrating the pinion allowed for more accurate measurements, with Method C the closest to the true size. Furthermore, the arrangement of teeth affected the measurement, but there was no continuous linear correlation with arch length discrepancy (ALD). Conclusions: Clinicians should choose appropriate measurement methods according to actual needs when performing model measurement, and should pay attention to the influence of tooth axis, tooth shape, and arrangement on the measurement results.

Validity and Reliability of Intraoral and Plaster Models' Photographs in the Assessment of Little's Irregularity Index, Tooth Size-Arch Length Discrepancy, and Bolton's Analysis.

Background Dental impressions have been required to obtain proper study models. This procedure is time- and labor-consuming for the orthodontist and could be exhausting to the patient, especially when braces are fitted in the context of a research project. This study aimed to assess the accuracy, reliability, and reproducibility of using intraoral photographs and plaster models' photographs in measuring Little's Irregularity Index (LII), tooth size-arch length discrepancy (TSALD), and Bolton's ratios. Methods A total of 52 dental arches of 26 patients were included in this study. Plaster models, occlusal intraoral photographs, and photographs of the collected plaster models were obtained for each patient. Then, LII, TSALD, and Bolton's ratios were measured using a manual caliper for plaster models' measurements and a software-based on-screen method for the photographs. Results The intraclass correlation coefficients (ICCs) of measurements made on intraoral photographs and photographs of plaster models were high (ranging from 0.90 to 0.99 and from 0.88 to 0.99, respectively), indicating a high level of agreement with the gold standard measurements. In addition, the differences were insignificant. The intra-/inter-examiner ICCs ranged from 0.90 to 0.99/0.92 to 0.99 and from 0.85 to 0.99/0.88 to 0.98 for plaster models and intraoral photographs of the dental arches, respectively. The analysis of reproducibility of capturing intraoral photographs of the dental arches on two different occasions showed high ICCs ranging from 0.96 to 0.99 with almost no significant differences between repeated measurements (P > 0.05). Conclusion LII, TSALD, and Bolton's overall and partial ratios can be measured from intraoral photographs of the dental arches with high accuracy, reliability, and reproducibility. Therefore, this methodology can be suggested for use in research projects when multiple records of the dental arches are required instead of depending on time- and labor-consuming procedures of ordinary dental impressions.

Comparative Study of Tooth Size and Arch Dimensions in Class I Crowded, Proclined Malocclusion and Class I Normal Occlusion.

AIM: The objectives are to compare the extent and to find whether it is arch dimension or tooth size that contributes to a greater extent to malocclusions such as dental crowding and proclination. MATERIALS AND METHODS: A total of 90 pretreatment models were selected and divided into three groups, namely uncrowded (Group-A), crowded (Group B), and proclination (Group-C). Measurements obtained were: (1) The largest mesiodistal width of each tooth on each arch (except the second and third molars), (2) Buccal inter-canine and inter-molar widths, (3) Lingual inter-canine and inter-molar widths, (4) Arch perimeters, and (5) Arch length. RESULTS: The mesiodistal teeth dimensions were higher in crowded and proclination group. Both inter canine width and inter molar width of maxilla were reduced in crowded group. Maxillary and mandibular arch perimeter and arch lengths were higher proclination group.

Does arch length preservation in mixed dentition children affect mandibular second permanent molar eruption? A systematic review and meta-analysis.

BACKGROUND: Arch length preservation strategies utilize leeway space or E-space in the mixed dentition to resolve mild to moderate mandibular incisor crowding. The purpose of this systematic review of the literature was to analyze the effects of arch length preservation strategies in on mandibular second permanent molar eruption. METHODS: A search for relevant articles published from inception until May 2020 was performed using PubMed/Medline, Cochrane databases, Clinicaltrials.gov, Google scholar and journal databases. Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were adopted for the conduct of the systematic review. Using RevMan 5.3 software, the most pertinent data were extracted and pooled for quantitative analysis with 95% confidence intervals. Heterogeneity was analyzed by using Cochran Q test and I squared statistics. RESULTS: A total of 5 studies involving 855 mixed dentition patients with arch length preservation therapy were included in the qualitative analysis. Pooled estimate of the data from two studies revealed 3.14 times higher odds of developing mandibular second molar eruption difficulty due to arch length preservation strategies using lingual holding arch (95% CI; OR 1.10-8.92). There was no heterogeneity found in the analysis. The certainty levels were graded as very low. CONCLUSIONS: This systematic review demonstrates that arch length preservation strategies pose a risk for development of mandibular second molar eruption disturbances, but the evidence was of very low quality. Registration number: CRD42019116643.

Accuracy of Model Estimation versus Tanaka and Johnston Arch Length Analysis.

OBJECTIVES: This study examines how accurate pediatric dentists are at estimating dental arch lengths by comparing their model estimations (guesstimating the arch length without measuring) to the Tanaka and Johnston mixed dentition arch length analysis. STUDY DESIGN: This study consisted of two parts, a survey of practitioners and a model estimating and measuring component. The survey was designed and given to 44 pediatric dentists to determine how many were practicing orthodontics and using arch length analyses routinely. Then 18 pediatric dentists and 13 pediatric dental residents examined 20 sets of mixed dentition models and estimated how much space was available. These estimations were compared to the calculated gold standard, the Tanaka and Johnston arch length analysis of the same models. RESULTS AND CONCLUSIONS: More than half of the dentists surveyed that practice comprehensive orthodontics use arch length estimates. Pediatric dentists and pediatric dental residents are just as good as each other at estimating arch length. Pediatric dentists and pediatric dental residents underestimated arch length by -3.6 and -3.1 mm, respectively. More research needs to be done to determine if model estimation is a clinically acceptable way to judge arch length.

Role of Facial Index and Odontometric Parameters in the Establishment of Stature and Gender of Individuals.

BACKGROUND: Dental anthropology is an important aspect of bioarchaeology and forensic anthropology. In forensic anthropological studies, identifying an unknown individual from a mangled and decomposing body is a challenging task. Cranial remains are the only critical clues available for personal identification. Age, sex, and stature are significant parameters in establishing the identity of an unrecognized individual. Stature is the natural height of the individual in an upright position. Stature can be estimated from various parts of the body such as long bones, short bones, and skull. Few studies conducted in specific population have established a correlation for predicting stature from cephalometric and odontometric parameters. Thus, the present study was conducted to determine stature and gender based on cephalometric and odontometric parameters in the population of Tamil Nadu. AIMS: The aim of this study was to investigate the possibility of predicting the stature and gender of an individual based on odontometric measurements, facial height, and bizygomatic width. MATERIALS AND METHODS: A total of seventy individuals in the age group of 18-24 years were selected for the study. The facial height, bizygomatic width and length ,mesiodistal and labiolingual diameter of clinical crown of maxillary central,lateral and canine teeth of both the right and left quadrants were measured. The values were analyzed statistically. Through this analysis, regression equations for estimation of stature from odontometric and facial index were derived. RESULTS: Pearson correlation test was carried out to establish a correlation between the stature and the measured parameters. Regression analysis was carried out to establish stature from the odontometric and facial index of the individual. The regression equations were used to get estimated stature in the same sample of volunteers from which regression equations were obtained. Tabulated results showed a probable correlation between various parameters. CONCLUSION: In our study, a positive correlation between cephalometric measurements, gender, crown length of permanent left central incisor, and combined mesiodistal diameter of permanent maxillary anteriors with stature was found. This can be used as a supplementary method for estimating the stature of unknown human bodies.

Factors influencing different types of malocclusion and arch form-A review.

AIM: This review intends to highlight malocclusion as a multifactorial issue and review the different factors that influence different types of malocclusion and arch form. METHODS: An online article search was performed on the factors influencing malocclusion and arch form from January 1990 through April 2020. The search was performed within the Google, Rutgers library, PubMed, MEDLINE databases via OVID using the keywords mentioned in the PubMed and MeSH headings for the English language published articles January 1990 through April 2020, which evaluated different factors that influence malocclusion and arch form. RESULTS: Of the 300 articles found in initial search results, 31 articles met the inclusion criteria set for this review. These 31 studies were directly related to the factors that impact malocclusion and different arch forms. CONCLUSION: Genetic inheritance, genetic mutations, age, gender, ethnicity, dental anomalies like macrodontia, congenital diseases, muscular diseases, hormone imbalance, and human behaviour are all factors that influence malocclusion and arch forms. The elements within the individual's control like behaviours can aid in preventing malocclusion. However, it seems as if the underlying reason for most of these factors indicates that malocclusion is a by-product of genetics and pathology.

Effects of Combined Rapid Maxillary Expansion and Facemask Therapy on the Mandibular Dental Arch in Mixed Dentition.

OBJECTIVE: The aim of this study was to evaluate changes in the mandibular dental arch and incisor alignment induced by combined bonded Rapid Maxillary Expansion (RME) and Face Mask (FM) therapy in the mixed dentition stage in which leeway space was used throughout the treatment. STUDY DESIGN: This retrospective study evaluates pretreatment (T0) and posttreatment (T1) cephalometric radiographs and orthodontic models of 25 patients (mean age: 10.75±2.64), in mixed dentition, having skeletal Class 3 anomaly (ANB<0) with maxillary retrognatism (SNA=77.2±0.68) and bilateral posterior crossbite treated with bonded Hyrax RME-FM. Mean treatment duration was 10.4 months. Dental model measurements were performed using the 3Shape OrthoAnalyzerTM 2013-1 program. Changes in the mandibular incisor and first molar positions were determined on cephalometric radiographs. Statistical evaluation was done with a paired t-test. RESULTS: A significant increase of 1.2 mm was found in intermolar width (p<0.001) in the mandibular dental arch. There was a significant decrease (1.4 mm) (p<0.001) in arch depth and an increase in arch length discrepancy (1.7mm)(p<0.01). There was a significant increase (0.8mm) (p<0.05) in the incisors' irregularity score (LII). IMPA showed a significant decrease (p<0.05). CONCLUSION: Clinicians should be aware that mandibular crowding tends to increase during this type of combined therapy.

Evaluation of the Reliability, Reproducibility and Validity of Digital Orthodontic Measurements Based on Various Digital Models among Young Patients.

The advantages of intraoral model scanning have yielded recent developments. However, few studies have explored the orthodontic clinical use of this technique particularly among young patients. This study aimed to evaluate the reliability, reproducibility and validity of the orthodontic measurements: tooth width, arch length and arch length discrepancy in each digital model obtained by model scanner and intraoral scanner, relative to a plaster model. Arch length measured using two methods: curved arch length (CAL) measured automatically by digital program and sum of sectional liner arch length (SLAL) measured sum of anterior and posterior liner arch lengths. Arch length discrepancy calculated each arch length measurement methods: curved arch length discrepancy (CALD) and sum of sectional liner arch length discrepancy (SLALD). Forty young patients were eligible for the study. A plaster model (P), model-scanned digital model (MSD) and intraoral scanned digital model (ISD) were acquired from each patient. The reliability of the measurements was evaluated using Pearson's correlation coefficient, while the reproducibility was evaluated using the intraclass correlation coefficient. The validity was assessed by a paired t-test. All measurements measured in P, MSD and ISD exhibited good reliability and reproducibility. Most orthodontic measurements despite of CAL in MSD exhibited high validity. Only the SLAL and SLALD in ISD group differed significantly, despite the good validity of the tooth width, CAL and CALD. The measurements based on the digital program appeared high reliability, reproducibility and accurate than conventional measurement. However, SLAL and SLALD in ISD group appeared shorter because of distortion during intraoral scanning. However, this could be compensated by using digital programed curved arch. Although the validity of SLAL and SLALD in the ISD group differed statistically, the difference is not considered clinically significant. Although MSD and ISD are acceptable for a clinical space analysis, clinicians should be aware of digital model-induced errors.

The impact of playing wind musical instruments on the dental arch dimensions in a male west african population.

BACKGROUND: Dental arch dimensions are important considerations in orthodontic treatment planning and monitoring. OBJECTIVE: This study aimed to compare the dental arch dimensions in wind and non-wind instrument players (WIP and non-WIP). METHODS: This was a cross-sectional study which compared a group of 50 male subjects aged 18-45 years that had been playing wind instruments for a minimum of 2 years with a control group matched for age in the same environment. The arch dimensions were assessed for both groups by measuring their dental casts using a digital caliper. Data was analyzed using statistical Software Package for Social Sciences (SPSS Inc, Chicago, IL) version 17. Statistical significance level was set at P < 0.05. RESULTS: The mean number of years of playing wind instrument among the WIP was 9.26 ± 6.21 years. All the maxillary arch dimensions were larger in the WIP group except for the palatal depth while the mandibular arch parameters in the non-WIP group were larger than the WIP group except the mandibular arch length. The differences were not statistically significant (P > 0.05). The mean maxillary inter-canine width (37.48 ± 1.12 mm), inter-molar width (57.27 ± 1.99 mm), arch length (29.80 ± 2.2.09 mm), and palatal depth (22.21 ± 2.33 mm) for class B instrument (Saxophone and clarinet) players were larger than either the class A instrument (Trumpet and trombone) players or the non-WIP group. These differences were not statistically significant (P > 0.05). CONCLUSIONS: Playing a wind instrument as well as the type of instrument played, duration, and frequency of play did not significantly affect dental arch dimensions.

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.

[Applicability of the Moyers mixed dentition analysis for the Hungarian population]. / A Moyers-féle vegyes fogazati analízis alkalmazhatóságának vizsgálata a magyarországi lakosság körében.

Introduction: Moyers mixed dentition analysis is one of the most commonly used prediction methods to estimate the size of the unerupted teeth. By its use, we can determine the severity of tooth size-arch length discrepancies in mixed dentition. Since the tooth size may vary considerably among different ethnic groups, for the most precise estimation of the required space, an analysis based on the individual's own ethnic group would be recommended. Aim: Our aim was to evaluate the applicability of Moyers mixed dentition analysis for the Hungarian population. Method: Upper and lower study casts of 370 patients were evaluated. The mesiodistal widths of the teeth were measured by using a Pittsburgh digital caliper. The odontometric values obtained were used to calculate actual and predicted values. The actual teeth measurements were then statistically compared to the predicted values derived from Moyers probability tables. Results: Using Moyers analysis, we found significant differences at each percentile between the actual and predictive values in both sexes. In the upper jaw, values for men at the 95th, 85th, 75th, and 65th percentile overestimated the actual values, while for women only the 65th percentile underestimated it. In the lower jaw, all values were overestimated in relation to the actual measurements at all percentiles. Conclusions: Based on our results, Moyers mixed dentition analysis cannot be reliably applied for the Hungarian population. If used, it is recommended to use the Moyers predicted values at the 65th instead of the 75th percentile, as this will result in closer estimation to the actual space requirements. Orv Hetil. 2019; 160(50): 1984-1989.

Factors influencing dental arch form.

Dental arch length, bilateral intermolar distance, morphology of the anterior teeth, and bilateral intercanine distance have been reported as factors influencing the determination of dental arch form. However, studies evaluating the factors that influence the determination of the above-mentioned components are limited. Therefore, to verify these points, the present study aimed to examine factors influencing the determination of dental arch form using statistical methods.Data obtained from sample dental casts were analyzed using principal component and cluster analyses. By principal component analysis, 23 sets of information were summarized into three components for the maxilla and four for the mandible. As a result of cluster analysis using principal component scores, the maxillary and mandibular dental arches were classified into four forms, respectively.Dental arch length is an important indicator of dental arch size and is influenced by the bilateral interincisor distance of the maxilla and mandible, and the mesiodistal crown width of the incisors and premolars. In the mandible, canine width also affects dental arch length. Dental arch width also influences the determination of dental arch form. However, the distance between the anterior teeth and the distance between the molars are independent and have no effect on each other.

A New Method for Prediction of Dental Arch Perimeter.

PURPOSE: Dental arch length, width, and perimeter are considered to be important for the diagnosis and treatment of orthodontic cases. This study aimed to utilize dental arch width and length to create an equation for predicting dental arch perimeter. MATERIALS AND METHODS: Sixty-seven pairs of study models for patients with normal occlusion who received dental treatment were included in this study. Dental arch width at the level of the canines, first premolars, and first molars, in addition to dental arch length and perimeter, were measured using a digital vernier with 0.01mm accuracy. Data were subjected to step-wise regression analysis to determine the major predictors of arch perimeters and develop regression equations for both arches. The predicted arch perimeters were compared with the actual measured values using paired sample t-test. RESULTS: For both arches, the perimeter showed a direct, moderate to strong, highly significant correlation with the length and width measurements. Findings from step-wise regression analysis indicated that there was a strong correlation between arch perimeter and the inter-canine width and arch length, which explained 67.7% of the variation in arch perimeter in the maxillary arch. In the mandibular arch, inter-molar width, inter-canine width, and arch length explained 55.1% of the variation in the dental arch perimeter. The arch perimeter values predicted from the developed equations were not significantly different from the actual values that were measured. CONCLUSION: New regression equations based on dental arch width and length at the level of the premolars, molars, and canines were developed to predict dental arch perimeters for both the mandibular and maxillary arches.