Equation for Tooth Size Prediction from Mixed Dentition Analysis for Taiwanese Population: A Pilot Study

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.

The Applicability of the Moyers, Tanaka-Johnston, and Gross-Hasund Analysis and a New Formula for the Vietnamese Population

Aim

Our aim is to determine the applicability of other analyses and develop a new formula appropriate for the Vietnamese population.

Materials and Methods

A cross-sectional descriptive analysis was conducted on a total of 120 dental arch samples (18-25 years old, 60 males, and 60 females) with <5 mm of tooth crowding, complete teeth on the dental arch, no missing teeth, and no fillings on the mesial or distal sides. Each study sample will be imprinted and measured using conventional as well as digital methods.

Result

There was a significant discrepancy between the overall mesiodistal width from canine to second premolar in the maxilla and mandibular measured with electronic calipers on the cast model and the values calculated by the Moyer, Tanaka - Johnston, Gross - Hasund formulae in the mandibular, and measured by digital scanning and results calculated by the Gross-Hasund formula for maxilla and mandibular and the Moyers, Tanaka-Johnston formula for mandibular. The values obtained were compared with those calculated using the Moyers, Tanaka-Johnston, and Gross-Hasund formulae for the mandibular. Additionally, measurements were taken by digital scanning, and the results were calculated using the Gross-Hasund formula for both the maxilla and mandibular, and the Moyers and Tanaka-Johnston formulae for the mandibular. When used to estimate space analysis in the Vietnamese population, the estimation formula for each gender had greater accuracy and reliability than other widely used methods.

Conclusions

As the central incisor and first molar are the first permanent teeth to erupt, the mesiodistal width may be readily measured. This new formula may be used to predict the width in the early stages of the mixed dentition.

Application of Moyer's mixed dentition analysis and establishing probability tables in a sample of Pakistani population

Objective

To assess the congruity of Moyers' dental analysis in Pakistani individuals and to make tables foreseeing the size of non-erupted permanent premolars and canines in children.

Methods

A cross-sectional study was conducted at Orthodontics Department of Armed Forces Institute of Dentistry (AFID) Rawalpindi, Pakistan. This was conducted from January 2020 to December 2021 and included mixed dentition subjects' casts. Mesiodistal widths (MDW) of the permanent dentition were estimated and contrasted with the anticipated values that emerged from the Moyer's mixed dentition examination. Students t-test, simple linear regression and Pearson correlation coefficient examination were utilized for statistical correlation. All data was gathered utilizing an electronic digital caliper and further investigated through IBM SPSS Statistics 24.

Results

Dental casts of the 258 subjects, 106 (41%) males and 152 (58.9%) females with the ages ranging 15.825±2.95 years were analyzed. Tooth size contrasts were significant (p <0.05) which was noticed in comparison to Moyer's predictive table. This demonstrates a bigger tooth size in young men than in young ladies. New probability tables were created through linear regression equations for our population.

Conclusion

Moyer's prediction cannot be applied to the Pakistani population. Mandibular incisors in addition to maxillary first molars are superior in prediction for the size assessment of canines and premolars (cp) that are unerupted in males and upper arch only in females. Another noteworthy conclusion is that in our study sample, in lower arch of females, the width of mandibular molars with mandibular incisors predicts better.