The Role of Maxillofacial Structure on Condylar Displacement in Maximum Intercuspation and Centric Relation.

Ilona Radej,Izabela Szarmach,Konstantinos Michalakis

doi:10.1155/2022/1439203

Ilona Radej, Izabela Szarmach + Show 1 more

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https://doi.org/10.1155/2022/1439203

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Abstract

Purpose This study is aimed at evaluating the impact of the craniofacial structure and occlusal conditions on the position of the articular heads of the mandibular condyles in the maximum intercuspal position (MIP) and comparing the centric relation (CR) and MIP of the mandibular condyles prior to orthodontic treatment. Methods The studied group consisted of 33 women and 15 men (median age of 17.75 years). Contact points of opposing teeth in the MIP were assessed by hand-held casts. Condylar displacement (CD) in three spatial planes on both sides was measured on models mounted in an articulator using a mandibular position indicator (MPI). Patients were divided into groups according to craniofacial structures (vertical and horizontal growth directions). The Mann-Whitney, Kruskal-Wallis, post hoc Dwass-Steel-Critchlow-Fligner, and Pearson's χ2 independence tests as well as Spearman's nonparametric correlations were used in the statistical analyses. Results Within the limitations of this study, no statistically significant correlation of CD with certain cephalometric measurements from a lateral cephalometric radiograph (ANB, SN-ML, and SGo/NMe) was observed. Correlation, however, was found between condylar displacement in the transverse axis and the mandibular plane angle SN-ML (p = 0.033) and also between condylar displacement in the anteroposterior axis and a midline shift of the mandible (p = 0.041). The results revealed a relationship between Angle's classification of molar position on the right side and anteroposterior CD values (p = 0.006). Conclusions Cephalometric measurements cannot be used to predict CD at the level of the condyles. Analysis of occlusal conditions of models mounted in an articulator is desirable for patients with Angle's class I and lower jaw asymmetry.

Highlights

The centric relation (CR), which is defined as an optimal, orthopedically stable musculoskeletal position [1], provides maximum jaw stability and minimizes the force directed on each tooth during its functioning [2]
If occlusal interferences are present, seating of the condyles in CR will be prevented and they will undergo a forced displacement as to allow for a stable occlusion of the teeth—the maximum intercuspal position (MIP). Such condylar displacement (CD) from CR to MIP occurs in 83.3% of the untreated population [3, 4]
Electromyographic studies suggest that the position of the articular heads of the mandibular condyles in the CR, when the teeth are in the MIP, allows for more harmonious and less intense work of the masticatory muscles [5] and provides a clinically repeatable reference position for developing a functional treatment plan for occlusion [6]

Summary

Introduction

The centric relation (CR), which is defined as an optimal, orthopedically stable musculoskeletal position [1], provides maximum jaw stability and minimizes the force directed on each tooth during its functioning [2]. Electromyographic studies suggest that the position of the articular heads of the mandibular condyles in the CR, when the teeth are in the MIP, allows for more harmonious and less intense work of the masticatory muscles [5] and provides a clinically repeatable reference position for developing a functional treatment plan for occlusion [6]. For this reason, the orthodontist should take this position into account in order to provide maximum comfort posttreatment for the patient. Orthodontic treatment should be planned with the intent of achieving maximal conformity of the condylar processes’ positions in CR and MIP [2, 3, 7, 8]

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