Proposed classification for interproximal contacts of primary molars using CBCT: a pilot study

Abstract

Contact areas in primary teeth are known to be broader, flatter, Background: and situated more gingivally than in permanent teeth. The objective of the present study was to evaluate the different types of intact contact areas in primary teeth using cone beam computed tomography (CBCT) among children.A cross-sectional study was designed with 74 contacts from 28 Methods: existing CBCT images of patients aged between 3 and 14 years, obtained from the Indian Dental Education Academy, Chennai, India. The shape of the contact area was observed at three levels, the coronal, middle, and apical thirds, in three different sections of CBCT. The weighted Cohen's kappa values for inter-examiner reliability was 0.893 at baseline. Prevalence of the types of contact areas was expressed in the form of numbers and percentages.Results exhibited four different types of contact areas between the Results: primary molars, namely, O type, X type, I type, and S type, based on the shapes observed; hence, the proposed classification is referred to as OXIS. The most common pattern seen was I (66.2%), followed by X (21.6%), O (9.4%) and the least common was S (2.7%).The three-dimensional evaluation of intact interproximal contact Conclusion: areas between primary molars are of four types.

Prevalence and correlation of OXIS contacts using Cone Beam Computed Tomography (CBCT) images and photographs

“…The highest and the least prevalent contact in the mandible, however, was the I (80.5%) type and S (1.9%) type, respectively. Compared with previous studies, 11,12 the results of our study were in perfect agreement with respect to the most common contact but were contradictory with respect to the least common contact which was different in all the three different studies. Overall, the order from the most to the least common contact areas in this study was I (79.7%), X (10.0%), S (6.6%), and O (3.7%), respectively, which was not consistent with the results of previous studies, which reported an order of I > X > O > S 11 and I > S > O > X 12 .…”

“…Compared with previous studies, 11,12 the results of our study were in perfect agreement with respect to the most common contact but were contradictory with respect to the least common contact which was different in all the three different studies. Overall, the order from the most to the least common contact areas in this study was I (79.7%), X (10.0%), S (6.6%), and O (3.7%), respectively, which was not consistent with the results of previous studies, which reported an order of I > X > O > S 11 and I > S > O > X 12 . These differences in findings could be attributed to the significant difference in the sample size, which consisted of 1,343 contacts in this study compared with 74 contacts performed with CBCT images and 4,476 contacts in the clinical study.…”

“…Data collection was performed by a paediatric dentist (KM) who was previously calibrated by a subject expert and was blinded to participants’ information. The detailed process of calibration was explained in a previously published pilot study 11 . Before the investigation, 30 CBCT scans with 120 intact contacts (not included in this study) were screened by the examiner on two different occasions with an interval of two weeks.…”

“…Based on this length, the crown was divided into three equal portions namely the occlusal, middle, and cervical thirds. Following this, the type of contact area in between the mesial surface of the second primary molar and distal surface of the first primary molar was scored at the three different levels (occlusal, middle, and cervical thirds) in the axial section according to the OXIS criteria mentioned in a previously published study 11 . The scoring of the types of contact areas was performed separately for the maxilla and mandible.…”

“…Although it has been well‐documented in the literature that there is a significant association of closed contact types with proximal caries when compared with open contacts in posterior primary molars, 3,9,10 there is little information about the types of contacts in primary dentition. Recently, a retrospective cross‐sectional investigation was conducted 11 to assess the variations in contacts between primary molars as seen from the axial view. This study was performed on 28 existing CBCT images and identified four types of contacts in between the primary molars, that is, open contact (O), point contact (X), straight contact (I), and curved contact (S), based on their shapes.…”