PhD Scientific Days 2026

Dental Research

Evaluation of the effects of orthognathic surgeries on the temporomandibular joint using a mandibular movement analyzer device

Name of the presenter

Lőrincz, Gergely

Institute/workplace of the presenter

Department of Paediatric Dentistry and Orthodontics

Authors

Dr. Lorincz Gergely¹, Prof. Dr. med. habil. Rózsa Noémi Katinka¹, Dr. Bogdan Sandor², Dr. Nemes Balint¹
1: Department of Paediatric Dentistry and Orthodontics
2: Department of Oro-Maxillofacial Surgery and Stomatology

Text of the abstract

Introduction
The primary goal of orthognathic surgeries combined with orthodontic treatment is not only to improve facial aesthetics but also to establish proper oral function and orthopedic stability of the temporomandibular joint (TMJ). While aesthetic outcomes are well-documented in the literature, their three-dimensional effects on the condyle remain less investigated.
Aims
To evaluate changes in functional movements, we analyze the extremes of mandibular movements pre- and postoperatively. To examine TMJ orthopedic stability, we compare the discrepancy between the centric relation (CR) and maximum intercuspation (MIP) condylar positions before and after surgery.
Methods
10 patients (aged 19–55; 1 male, 9 females) treated at Semmelweis University are participating. Measurements are performed 1 month prior to surgery and 6–9 months postoperatively using the ARCUS Digma III (KaVo) digital 3D movement analysis device. Orthognathic surgeries are performed by Dr. Sándor Bogdán's team at the Dept. of Oro-Maxillofacial Surgery and Stomatology. Digital planning (IPS Case Designer) and splint manufacturing are performed at the Dept. of Paediatric Dentistry and Orthodontics. We record the extremes of functional movements (protrusion, retrusion, laterotrusion, maximum mouth opening) and condylar positions in MIP and CR. Software analysis evaluates the spatial discrepancy between the two positions with 0.1 mm precision. Ethical approval: SE RKEB No. 249/2024.
Results
Postoperative measurements showed a minimal, non-significant decrease in extreme right (−0.61 ± 3.85 mm) and left (−1.15 ± 4.89 mm) laterotrusion , protrusion (−0.62 ± 3.91 mm), while maximum mouth opening slightly increased (+1.71 ± 7.95 mm), confirming no overall functional impairment. The 3D spatial discrepancy between CR and MIP positions decreased for both condyles: For the right the mean distance decreased from 0.89±0.94 mm preoperatively to 0.33±0.17 mm postoperatively, for the left from 0.64±0.48 mm to 0.29±0.14 mm.
Conclusion
Orthognathic surgeries effectively maintain mandibular function while improving TMJ stability. The reduced CR-MIP spatial discrepancy indicates postoperative orthopedic stabilization, which can decrease the risk of temporomandibular disorder.
Funding: Supported by the "FOK Kari Kutatási Pályázat – 2026".