Tooth size ratios during orthodontic treatment for different arch length and arch perimeter groups need to be evaluated carefully.

In order to establish standard norms for the Pakistani population, we investigated the geomorphometrics of tooth size and arch dimension using a conventional digital caliper (DC) and a digital stereomicroscope (SM). The sample consisted of 128 subjects ranging in age from 18 to 24 years. A total of 44,155 variables were measured. Dental models of each subject for maxillary and mandibular arches were scanned via Hirox digital stereomicroscope for the fabrication of the digital models, and the geomorphometrics of tooth size and arch dimensions were measured via SM scanned digital models. All the measurements were also carried out via DC on plaster dental models. Sex differences and changes associated with methods were assessed, and interrelationships between different variables were explored within the study group. For the data obtained by DC and SM techniques, the men had significantly larger arch dimensions and geomorphometrics of tooth size than the women did. There were no significant disparities observed between the techniques. The developed norms for the mesiodistal, buccolingual, diagonal tooth sizes and arch dimension had significantly greater values for males in relation to females (*pd" 0.05 to ***pd" 0.001). This study has established a new reference database of tooth size and arch dimensions via both DC and digital SM for first time on Pakistani population. These norms will be helpful for clinical treatment planning in dentistry. Contemporaneously, the norms will be of great value to forensic dentists and dental anthropologists for making comparisons within and between different populations.

The purpose of this study was to evaluate the validity and reliability of orthodontic measurements made on digital models created with Hirox digital microscope (HDM). The data sources were plaster dental models from the archives of School of Dental Sciences, Universiti Sains Malaysia. A total of 11 dental models with 396 variables were measured using the plaster dental casts, and Hirox digital models were created. The study inclusion and exclusion criteria were followed. Two investigators (A and B) carried out the measurements of the selected dental casts using a digital caliper (DC) and the HDM. Dental plaster models were scanned using the HDM for the fabrication of the Hirox digital models. The tooth size and arch width were measured by DC and HDM. The validity of the digital measurements for examiners A and B the ICC coefficients were statistically significant (p<0.001), and the values of coefficient were in the range of strong correlation. The ICC coefficient values for inter-examiner A and B were all in the range of strong correlation for both tooth size and arch width variables in which the reliability coefficient values were comparable between digital measurements using HDM and measurements using DC. All ICC coefficient values were statistically significant (p<0.001). The results show that linear measurements of dental casts using a digital microscope are valid and reliable.

Aims: To correct the Angle class I malocclusion with crowding via four premolar extractions.Presentation of case:A 19-year-old Malaysian female presented with the bimaxillary protrusion, crowding, high canines, midline deviation and edge-to-edge anterior bite. Upper lateral incisors were palatalized and in crossbite interactions with the opposite teeth.Discussion: Treatment was initiated using fixed orthodontic appliances followed by four 1st premolar extractions in both arches. Case was finished with good inter cuspation of the upper and lower teeth. Molars were finished in a Class I relationship with canine guidance, and ideal overjet and overbite were obtained.Conclusion: Successful finishing of a case with beautiful smile, obtained proper overjet and overbite, corrected cross bite, midline shifting and the improved soft tissue profile.Bangladesh Journal of Medical Science Vol.17(4) 2018 p.683-687

Objective:To investigate the maxillary and mandibular anterior crown width/height ratio and its relation to various arch perimeters, arch length, and arch width (intercanine, interpremolar, and intermolar) groups.Materials and Methods:The calculated sample size was 128 subjects. The crown width/height, arch length, arch perimeter, and arch width of the maxilla and mandible were obtained via digital calliper (Mitutoyo, Japan). A total of 4325 variables were measured. The sex differences in the crown width and height were evaluated. Analysis of variance was applied to evaluate the differences between arch length, arch perimeter, and arch width groups.Results:Males had significantly larger mean values for crown width and height than females (P ≤ 0.05) for maxillary and mandibular arches, both. There were no significant differences observed for the crown width/height ratio in various arch length, arch perimeter, and arch width (intercanine, interpremolar, and intermolar) groups (P ≤ 0.05) in maxilla and mandible, both.Conclusions:Our results indicate sexual disparities in the crown width and height. Crown width and height has no significant relation to various arch length, arch perimeter, and arch width groups of maxilla and mandible. Thus, it may be helpful for orthodontic and prosthodontic case investigations and comprehensive management.