Review articles

By Dr. Leda M Valentini , Dr. Emanuele Fantasia , Dr. Anazoly Chudan Poma , Dr. Roberta Scarola , Dr. Diana Jamshir , Dr. Enrico M Pompeo
Corresponding Author Dr. Leda M Valentini
La Sapienza University, - Italy
Submitting Author Dr. Leda M Valentini
Other Authors Dr. Emanuele Fantasia
La Sapienza University, - Italy

Dr. Anazoly Chudan Poma
La Sapienza University, - Italy

Dr. Roberta Scarola
University of Bari, - Italy

Dr. Diana Jamshir
La Sapienza University, - Italy

Dr. Enrico M Pompeo
La Sapienza University, - Italy


mandibular asymmetries; temporo-mandibular disorders (TMD)

Valentini LM, Fantasia E, Chudan Poma A, Scarola R, Jamshir D, Pompeo EM. Correlations between mandibular asymmetries and temporo-mandibular disorders (TMD): literature review.. WebmedCentral ORTHODONTICS 2019;10(2):WMC005547

This is an open-access article distributed under the terms of the Creative Commons Attribution License(CC-BY), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Submitted on: 14 Feb 2019 04:57:18 PM GMT
Published on: 19 Feb 2019 07:21:05 AM GMT


Cranio-facial asymmetries, and in particular those with mandibular involvement, are a topic of great interest in modern literature, both for the different diagnostic frameworks of reference, and for the possible therapeutic approaches that can provide only orthodontics or in combination with maxillofacial surgery. One interesting aspect centered in international literature, as the topic of this work is to analyze the correlation between this characteristic and the appearance of temporo-mandibular disorders.

In fact, the purpose of this work is to study how mandibular asymmetries are factors that are etiological or predisposing to the development of temporomandibular disorders (TMD). To obtain this, it was analyzed articles related to the association between mandibular asymmetries and temporomandibular disorders.


A manual and electronic research was carried out in the main journals to select studies that evaluated the correlation between mandibular asymmetry and temporo-mandibular disorders. It was included in the research: randomized clinical trials, controlled clinical trials, cohort studies, retrospective studies and case series were, with the exclusion of animal studies, in vitro studies, case reports, letters to publishers and narrative or systematic reviews. In the end we selected 6 articles.


Through the review of the literature a series of observations emerged concerning the topic under investigation. According to one of the articles analyzed it can be argued that mandibular asymmetries can be considered as an etiological or predisposing factor for the development of temporo-mandibular disorders. In fact, a sample of 16 subjects aged from 14 to 36 years (11 females and 5 males) with mandibular asymmetries (structural asymmetry of 81%, functional asymmetry of 19%) with skeletal and dental malocclusion combined with different temporo-mandibular disorders. In 100% of these patients received orthodontic treatment. At the end of the treatment, a comparison was made between the postero-anterior cephalometric analysis (PA) pre- and post-treatment in order to evaluate the resolution of the asymmetry. This comparison showed the resolution of mandibular asymmetries and temporomandibular symptoms after treatment. Another article assesses whether the genes ACTN3, ENPP1, ESR1, PITX1 and PITX2 (genes contributing to sagittal and vertical malocclusions) also contributed to the determination of facial asymmetries and temporo-mandibular disorders (TMD) before and after treatment of orthodontics and orthognathic surgery. In this, 174 patients with a dentofacial deformity were subdivided, through the postero-anterior cephalometric measurements, into symmetric patient groups and into 4 subgroups of asymmetric patients; in addition, these patients were given questionnaires on the diagnosis of the TMD examination and on the pain and function of the jaw (JPF) with the aim of assessing the presence and severity of TMD. The classification of asymmetries showed significant cephalometric differences between symmetric and asymmetric groups and between 4 asymmetric subtypes: group 1: asymmetry of the mandibular body; group 2: asymmetry of the branch; group 3: atypical asymmetry; group 4: C-shaped asymmetry. Through genetic analysis it was possible to observe that ENPP1 SNP-rs6569759 was associated with group 1 (P = 0.004) and rs858339 was associated with group 3 (P = 0.002); ESR1 SNP-rs164321 was associated with group 4 (P = 0.019). These results were confirmed by the analysis of the main component that showed 3 main components that accounted for almost 80% of the variations in the studied groups. The main components 1 and 2 have been associated with ESR1 SNP-rs3020318. Average JPF scores for asymmetric subjects prior to surgery (JPF, 7) were significantly higher than symmetric subjects (JPF, 2). Patients in group 3 had the highest preoperative JPF scores and groups 2 and 3 were more likely to be cured of TMD 1 year after treatment. < 0.05).


The analysis of the 6 articles eviedenced that the diagnoses of disk dislocation with reduction, myalgia of masticatory muscles and arthralgia were highly prevalent in the asymmetry groups, and all had strong statistical associations. Through this study it was observed that orthodontic and orthognathic facial asymmetry treatments are effective in eliminating temporomandibular dysfunction in most patients and that postero-anterior cephalometry can classify asymmetry into distinct groups and identify the probability of associations of the temporomandibular disorders and of the genotype. Another article centered the interest on the topic by evaluating the correlation of the morphological discrepancy between the mandibular condyle and the temporomandibular joint (TMJ) and the displacement of the disk on the magnetic resonance (MRI). This study included 61 patients with unilateral internal imbalance based on both magnetic resonance and clinical examination. The coronal morphologies of the condyle and the fossa were divided into four groups. According to the coronal morphology of the condyle and the fossa, all the joints were dichotomized into harmonized groups or in a group of discrepancies (eg condilo angled and concave fossa). The incidence of discrepancy and the discrepancy relationship with other findings on magnetic resonance imaging were statistically evaluated. Through this analysis it was possible to observe that the discrepancy was correlated to the incidence of the deformity of the disk on the interested side.


In conclusion, from the following revision of the literature a correlation between mandibular asymmetry and temporo-mandibular disorders has been refuted since, in most of the articles, there is a link between the asymmetries and the reduction/resolution of the temporo-mandibular disorder of the patients on which it is performed.


1) An investigation of the simultaneously recorded occlusal contact and surface electromyographic activity of jaw-closing muscles for patients with temporomandibular disorders and a scissors-bite relationship. Author links open overlay panel Kun Qi Shao-Xiong Guo Yi Fei Xu Qi Deng Lu Liu Baoyong Li Mei-Qing Wang. Journal of Electromyography and Kinesiology. Volume 28, June 2016, Pages 114-122

2) Int Orthod. 2014 Jun;12(2):222-38. doi: 10.1016/j.ortho.2014.03.013. Epub 2014 May 10. Correlations between mandibular asymmetries and temporomandibular disorders (TMD). D'Ippolito S1, Ursini R2, Giuliante L2, Deli R3.

3) ENPP1 and ESR1 genotypes associated with subclassifications of craniofacial asymmetry and severity of temporomandibular disorders. Author links open overlay panel Kay Chunga Tabitha Richards Romain Nicot Alexandre R.Vieira Christiane V.Cruz Gwénaël Raoul Joel Ferri James J.Sciotea. American Journal of Orthodontics and Dentofacial Orthopedics. Volume 152, Issue 5, November 2017, Pages 631-645

4) Discrepancy of coronal morphology between mandibular condyle and fossa is related to pathogenesis of anterior disk displacement of the temporomandibular joint. Author links open overlay panel Kunihito Matsumoto DDS, Da Shigeo Kameoka DDS, Toshihiko Amemiya DDS, Hisaya Yamada DDS, Masa Araki DDS, DdKazuoIwai DDS, Dd Koji Hashimoto DDS, De Kazuya Honda DDS, Df. Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology Volume 116, Issue 5, November 2013, Pages 626-632

5) Common symptoms of temporomandibular disorders do not mean same treatment plans: A case series. Maria Paco, Paula Chaves, Francisco Pinho, Carolina Lemos, Rui Costa, Jose A. Duarte ,Teresa Pinho

6) Temporomandibular Joint Disorders and Orofacial Pain. Mansur Ahmad, BDS, PhD Correspondence information about the author BDS, PhD Mansur Ahmad Email the author BDS, PhD Mansur Ahmad, Eric L. Schiffman, DDS, MS University of Minnesota School of Dentistry, 515 Delaware Street Southeast, Minneapolis, MN 55455, USA

Source(s) of Funding


Competing Interests


0 reviews posted so far

0 comments posted so far

Please use this functionality to flag objectionable, inappropriate, inaccurate, and offensive content to WebmedCentral Team and the authors.


Author Comments
0 comments posted so far


What is article Popularity?

Article popularity is calculated by considering the scores: age of the article
Popularity = (P - 1) / (T + 2)^1.5
P : points is the sum of individual scores, which includes article Views, Downloads, Reviews, Comments and their weightage

Scores   Weightage
Views Points X 1
Download Points X 2
Comment Points X 5
Review Points X 10
Points= sum(Views Points + Download Points + Comment Points + Review Points)
T : time since submission in hours.
P is subtracted by 1 to negate submitter's vote.
Age factor is (time since submission in hours plus two) to the power of 1.5.factor.

How Article Quality Works?

For each article Authors/Readers, Reviewers and WMC Editors can review/rate the articles. These ratings are used to determine Feedback Scores.

In most cases, article receive ratings in the range of 0 to 10. We calculate average of all the ratings and consider it as article quality.

Quality=Average(Authors/Readers Ratings + Reviewers Ratings + WMC Editor Ratings)