Three-dimensional evaluation of the relationship between dental and basal arch forms in normal occlusion

Abstract

Objective:The purposes of this study were to evaluate the relationship between the dental and basal arch forms; to analyze their differences in the tapered, ovoid, and square arch forms in normal occlusion by using three-dimensional (3D) virtual models; and to test the hypothesis that the overjet and maxillomandibular basal arch width difference have a significantly positive correlation. Methods: Seventy-seven normal occlusion plaster casts were examined by 3D scanning. Facial axis (FA) and WALA points were digitized using the Rapidform 2006 software. The dimensions of the dental and basal arches and the overjet were measured. The samples were classified into 3 groups according to arch forms: tapered (n = 20), ovoid (n = 20), and square (n = 37). Analysis of variance (ANOVA) was used to compare the dental and basal arch dimensions. The Pearson correlation coefficients between the intercanine as well as the intermolar widths at the FA and WALA points were calculated. Results: With regard to the basal arch dimensions, the tapered arch form showed a larger mandibular intermolar depth than the ovoid. Strong correlations were noted between the basal and dental intermolar widths in both the upper and lower arches (r = 0.83 and 0.85, respectively). Moderate correlation was found between the upper and lower intercanine widths (r = 0.65 and 0.48, respectively). Conclusions: The 3 dental arch form groups differed only in some dimensions of the skeletal arch. Moderate correlations were found between the basal and dental intercanine widths. These findings suggest that the basal arch may not be a principle factor in determining the dental arch form. (Korean J Orthod 2011;41(4):288-296)

Archform Comparisons between Skeletal Class II and III Malocclusions

“…Ball [6] compared the relationship between dental and basal archforms in Class II Division 1 and Class I patients, and a relationship was observed between FA and corresponding WALA points in canine and molar areas (R 2 = 0.843, 0.847). However, Kim [7] reported a moderately relevant relationship in dental and basal archforms in the canine region for normal occlusion samples (r = 0.48), and these results agreed with our findings.…”

“…They concluded that the WALA ridge estimates the basal bone archform. In other several studies [7] , [8] , the WALA points also have been used to refer the basal bone arch form,proven reliable to represent the basal bone archform.…”

Preform ark tellerinin dental arklar üzerine etkilerinin 3D model analizi ile değerlendirilmesi

“…3,[9][10][11] Teknolojinin gelişmesi ile birlikte 3 boyutlu (3D) analizlerin yapılabilir olması araştırmacıların daha gerçekçi ölçümler yapabilmek üzere farklı referans noktaları kullanımlarına olanak sağlamıştır. 12,13 Çekimli ve çekimsiz sabit ortodontik tedaviler sonucu ark genişliklerinin ve uzunluklarının değiştiği bir çok çalışmada gösterilmiştir. 14,15 Bu çalışmanın amacı minimal çapraşıklık vakalarında uygulanan sabit ortodontik tedavilerde kullanılan preform ark tellerinin alt ve üst çene dental ark formu üzerine etkilerinin üç boyutlu olarak değerlendirilmesidir.…”

Is there a relationship between dental crowding and the size of the maxillary or mandibular apical base?

“…11 Points on dental casts adjacent to the mucogingival junction (ie, the WALA ridge, named for Will Andrews and Larry Andrews who made the discovery) have also been used, with significant associations reported between WALA ridge dimensions and dental arch dimensions. [12][13][14] These relations should be expected and are also spurious because the limits of the WALA ridge landmarks were dentally defined.…”