Accuracy of check‐bite registration and centric condylar position

Abstract

In a dentate subject a jaw relation can either be determined in maximum intercuspation and is as such given by the occlusal morphology, or the mandibular position can be allocated according to the centric position of the condyles. For comprehensive restorative treatment or analytic measures of the occlusion it is important to record the centric condylar position. Various registration methods have been described in the literature, but there is no consensus on which is the 'best'. The aim of the present study was therefore to assess the accuracy of various registration methods and evaluate a possible influence of the used materials. Four dentists were involved in the clinical part of the study, another was responsible for the measurements. Impressions were taken from 81 fully dentate volunteers. The casts were mounted by face-bow transfer and central-bearing-point (CBP) registration into Dentatus articulators. Subsequently the centric condylar position was determined with six different methods and materials, respectively. Each method was reproduced twice so that a total of 18 registrations was performed per patient. The mandibular positions which resulted from the individual registrations were then repeatedly compared in the condylar area using a computer supported specially modified measuring articulator. The accuracy was found best for the unrefined wax wafer registration (x=0.33 mm) and with an average of 0.44 mm worst when using acrylic wafers. The CBP and frontal jig methods as well as tin-foil and refined wax wafers showed an accuracy in-between these boundaries. The biggest measured mandibular displacement between any two registrations were considerably 2.0 mm. However, the described differences in accuracy between the various methods and materials proved statistically not significant. All investigated jaw registrations showed an accuracy of about 20 times the tactile fine sensibility of natural teeth which has to be taken into account when inserting fixed prosthetic restorations in centric condylar position. Despite meticulous clinical and technical procedures small occlusal adjustments are therefore almost unavoidable.

Condylar positions generated by five centric relation recording techniques

“…The subjects were from 26 to 36 years of age and met the following inclusion criteria: [1] not undergoing orthodontic treatment [2]; absence of temporomandibular joint signs and symptoms [3]; a complete dentition excluding the third molars; and [4] in good health. The rights of all subjects were protected and the study was approved by the Colorado Multiple Institution Review Board.…”

“…At present, there is no established "gold standard" method of recording patients' centric relation (CR) position [1][2][3]. Rather, many different techniques are surrounded by open-ended controversy regarding their comparative reproducibility and/ or accuracy or even the necessity of mounting study casts in CR [4].…”

Recording the retruded contact position: a review of clinical techniques

“…It was found that the dominant influence upon reproducibility was clinical technique rather than recording medium or the particular mandibular position recorded. Conversely, Utz et al 60 has suggested that reproducibility is unachievable, regardless of technique or technical excellence. Utz et al 60 may be right in that absolute reproducibility of RCP is impossible, however differences of 0.08 mm have lead Posselt 15 to conclude that these variations are 'probably clinically insignificant'.…”

Centric relation in prosthetic rehabilitation

“…Znaczenie mają między innymi umiejętności operatora, zastosowana metoda, czas rejestracji, stan nerwowo-mięśniowy pacjenta oraz zastosowanie odpowiednich materiałów do rejestracji zwarcia. 54,55 Optymalny materiał do rejestracji położenia żuchwy względem szczęki powinien wykazywać niską lepkość początko-wą, a po związaniu być sztywny i stabilny objętościowo. [56][57][58] Jest wiele materiałów, które mogą być stosowane do rejestracji położenia żuchwy w relacji centralnej, jednak wszystkie one posiadają wady i zalety.…”