Examination of Palatal Mucosal Relief in Normal Occlusion Patients

Although its discussional stability, the position of primary rugae distal edges was examined for two reasons: on one hand, it was provoked by Van der Linden’s clinical study on the stable and constant position of the first rugae in relation to canines and on the other, by the lack of published research results on this issue in Bulgarian medical literature. From anatomo-topographic point of view, the first rugae are disposed just behind sutura incisiva with its onset between the lateral incisives and canines. Most frequently, the first ruga is fastened to the palatal suture on a quite large basis. Having in mind that the palatal mucosa and teeth have common ectodermal origin and the genetic determination of relief reveals yet in embryonic development, the elucidation of the relationship between them is of special interest. Our study on first ruga position determining the commencement of rugal zone aimed at establishing the stability of rugal position in orthodontically non-treated Class I intact dentitions and at its possible use as a reference for comparisons. Our study used the classical anthropologic method of Martin-Saller and the method of Jordanov. The study group included 80 Bulgarian students at the Faculty of Dental Medicine, Medical University – Sofia, from both sexes (42 males and 38 females) with intact dentition and normal occlusal proportions – Class 2 (orthognatic occlusion) and non-treated orthodontically. The analysis of mucosal relief components showed that three shapes of papilla incisiva were most commonly observed: oval (31.3%), pear-shaped (23.8%) and flame-shaped (17.5%). This corresponded with the shape types and respective frequencies found by the population study among Bulgarians. The analysis of the type of rugal zone relief showed that in normal occlusion subjects, type A (three primary rugae) was mainly observed. These data were similar to those obtained for adult Bulgarians. The distal border in normal occlusions was rather symmetric than asymmetric. Our research data for the medial rugae disposition in relation to canines revealed that almost 1/2 of the cases (38) (47.5%) displayed bilaterally symmetric disposition of medial (primary) ruga against the canine tooth. The medial (primary) rugae were projected in right in 92.6% of the cases and in left in 87.8% of the cases, within the limits of the canine mesiodistal diameter as the significant frequency of this position give grounds for its acceptance as a norm/reference.