Prevalence and severity of temporomandibular joint disorder in partially versus completely edentulous patients: A systematic review

Abstract

Temporomandibular joint disorders (TMDs) following tooth loss may or may not be prevalent, but the risk of developing these disorders is always there due to changes in occlusion and vertical dimension, leading to changes in the disc-fossa relationship. The purpose of this systematic review was to evaluate the prevalence and severity of temporomandibular joint (TMJ) disorder in partially versus completely edentulous patients. An elaborated literature search was conducted in PubMed/Medline, Scopus, Web of Science, Lilacs, and Google Scholar databases including all articles about varied effects of partial and complete edentulism on the TMJ published from January 1, 2000, to January 1, 2022. After the meticulous screening, only publications which fulfilled the inclusion parameters were ultimately selected for full-text evaluation and tested for bias using the Joana Briggs Institute Appraisal tools for cross-sectional, case–control, and cohort studies. A total of 547 articles from various electronic databases and manual searches were found. After eliminating the duplicates and thorough screening, 13 studies were included for qualitative synthesis. Most of the studies demonstrated at least one or two signs of the presence of TMDs following tooth loss, the intensity/frequency of which increased in proportion to the number of missing teeth.

INTRODUCTION

The temporomandibular joint (TMJ) is a synovial sliding-ginglymoid joint that is an intricate neural-muscular system working in harmony with the adjacent structures. It is also a three-point articulating joint, with the condyle-fossa being two points of contact and the dentition being the third. If one of these components is altered, the other two will also undergo secondary morphological alterations.[1]

In the human body, the occlusion, craniosacral system, and functional systems are intricately intertwined in a dynamic equilibrium.[2] The phrase “temporomandibular disorder” refers to various conditions that clinically affect either the masticatory musculature, the TMJ and related tissues, or both.[3] Occlusion is believed to have a role in the etiology of temporomandibular joint disorders (TMDs).[4,5] Long-term loss of occlusal support can cause drifting of remaining teeth, changing occlusal contacts, and increasing the risk of TMDs.[6,7] Although many patients are able to adjust to condylar or occlusion positions that are not ideal when teeth are lost, especially posterior teeth, adaptive mechanisms set in to make up for the misalignment. If the joint’s adaptive capacity is exceeded, other patients may develop degenerative joint disease.[8-10] Due to a change in the vector of force that alters biomechanical alterations during function and is followed by a change in the morphology of the glenoid fossa that alters in accordance with the dental pattern (if these changes occur), the morphology of the disc may be permanently altered.[11-14]

The rate of development of these disorders, if not timely rehabilitated in a partially edentulous population, may differ from that of the completely edentulous population, and the severity might also differ. This may further lead to pain and difficulty in mastication, thus affecting the overall health of the individual. Although studies have evaluated the presence of TMD following partial/complete tooth loss, no systematic review has been done comparing the prevalence and severity of TMD after partial or complete tooth loss. As a result, the purpose of this systematic review was to assess and compare the parameters. The null hypothesis stated that there would be no difference in both predominance and severity of TMJ issues between the group of people who were partially and totally edentulous.

MATERIALS AND METHODS

The present systematic review procedure has been registered under registration number CRD42022358477 at the National Institute of Health Sciences, International Prospective Register of Systematic Reviews database. The data were searched according to Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines.[15,16]

The review question “Amongst the elderly population with partially or completely edentulous arches what is the prevalence and severity of TMDs?” was formulated using patient, intervention, comparator, outcome, studies framework [Table 1] followed by an assembled search strategy, specifying inclusion and exclusion criteria, the identification and selection of studies, the evaluation of the quality of the research, the extraction of data and the creation of an evidence table, and interpretation.

Table 1.

Patient, intervention, comparator, outcome, studies strategy

Elements	Contents
Population (P)	Patients of 35 years of age and above with partially (either or both maxillary and mandibular arches) and completely edentulous arches free of any systemic health condition and not wearing any prosthesis
Intervention (I)	Prevalence of TMDs in patients 35 years of age and above with partially and completely edentulous arches free of any systemic health condition and the severity they might develop if not timely rehabilitated
Comparator (C)	Prevalence and severity of TMDs in partially versus completely edentulous patients
Outcome (O)	Prevalence and severity of TMDs in patients with partially (either or both maxillary and mandibular) arches versus completely edentulous arches if not timely rehabilitated
Study design (S)	Cross-sectional, case–control, and cohort (prospective and retrospective) studies

TMDs: Temporomandibular joint disorders

The inclusion criteria included systematic reviews and meta-analysis, observational, and cross-sectional studies published in English from January 1, 2000, to January 1, 2022, involving patients of 35 years of age and above with partially (either or both maxillary and mandibular arches) and completely edentulous arches free of any systemic health condition without any prosthetic rehabilitation. Case reports, case series, articles in non-English languages, and research that did not meet the inclusion requirements were included under the exclusion criteria.

PubMed/Medline, Scopus, Web of Science, Google Scholar, and Lilacs databases were searched electronically along with a manual search of the references and citation analysis. For data search, the medical subject heading terms (MeSH) utilized were “temporomandibular disorders,” “temporomandibular diseases,” “TMJ changes after tooth loss,” “missing posterior teeth,” “partially edentulous,” “completely edentulous,” and “radiographic changes in TMJ following tooth loss.” Following a rigorous screening of search results against eligibility criteria and data extraction, two independent reviewers (PR and PS) conducted a literature search. Two authors (DS and AS) independently assessed the bias risk in the included studies using a quality assessment checklist for cross-sectional studies, case–control studies, and cohort studies that was adapted from the checklist for Critical Appraisal by Joanna Briggs Institute. The third author (AS) was contacted in the event of a disagreement. A study was deemed to have a low risk of bias when the “yes” score was more than 70%, a moderate risk of bias when the “yes” score was between 50% and 69%, and a high risk of bias when the “yes” score was ≤49% for every article.[17,18] This scoring was finalized after consulting with all the authors. The studies that were included in the data extraction process were sorted and tabulated in chronological order. The summarized data from these included studies were listed.

RESULTS

Initial electronic and manual searches identified 547 studies (PubMed/Medline = 72, Scopus = 22, Web of Science = 15, LILACS = 34, Google Scholar = 132, and manual search = 272). Two independent reviewers (PR and PS) carried out the initial screening of titles and abstracts after the duplicates (n = 204) were eliminated. Full texts of 132 studies were acquired after a screening of the title and abstract. Following a full-text review, 43 papers were included. Finally, after the risk of bias assessment and due to various other reasons, a total of 13 studies (8 cross-sectional, 4 case–control, and 1 cohort study) were included for qualitative synthesis. The selection process for the study is presented in Figure 1.

Figure 1.

Study selection process

Since the present review aims to compare the prevalence and severity of TMDs in partially and completely edentulous patients, all the included studies were divided into partially (11 studies) and completely edentulous (2 studies) groups, respectively. A total of 2788 patients with missing teeth were examined either clinically or both clinically and radiographically for TMDs. In all the included studies, the clinical assessment was used as a diagnostic modality for assessing TMJ changes followed by 4 studies that had questionnaire and clinical assessment, 2 studies that reported radiographic along with clinical assessment, and 1 study that adopted logistic regression analysis for assessing TMJ changes following tooth loss. The clinical assessment involved the evaluation of Joint sounds, joint pain, muscle pain/tenderness, and mandibular deviation. For radiographic evaluation, Tallents et al.[19] used magnetic resonance imaging and Bertram et al.[20] used cone-beam computed tomography apart from clinical assessment for assessing TMJ changes following tooth loss.

In all the included studies, for both partially and completely edentulous groups, a strong association was found between missing teeth and the development of one or more than one symptom of TMDs, except for one study by Reshmi et al.,[21] which demonstrated a low prevalence of TMDs (P = 0.064) in partially edentulous patients. Among all the included studies, six reported[22-27] presence of abnormal TMJ sounds as one of the most common complaints of patients following tooth loss. Few of the studies also provided data on gender predilection in the development of TMDs after tooth loss. Four studies[21,25-27] concluded that females had more incidence of TMDs following tooth loss than males, while only one study[22] reported the opposite. Two studies having patients with partially edentulous arches compared TMD symptoms in Kenndy Class I versus Class II cases, in which one study concluded that patients with a Kennedy’s Class I mandibular condition or a combination of Class I and Class II situation in the maxilla and mandible showed a higher prevalence of TMD,[21] whereas the other study concluded that contrary to the unilateral loss posterior tooth, the bilateral loss posterior tooth is associated with a more pronounced increase in cranial condyle displacement and condylar erosion.[20]

On the evaluation of the bias risk, it revealed that most of the cross-sectional studies (n = 4; 50%) exhibited a moderate bias risk overall; however, three studies (37.5%) had a low bias risk and one study (12.5%) had a high risk of bias. Similarly, among case–control studies, 2 studies demonstrated a moderate risk of bias, and 2 showed a low risk of bias. Furthermore, a moderate risk of bias was observed in one cohort study reported in this systematic review. A compilation of the extracted data from all of the included studies is depicted in Table 2.

Table 2.

Extracted data from all the included studies

Author/year	Study type	Sample size	Status of edentulousness	Diagnostic modality/assessment used for evaluation of TMJ disorder	Outcomes (TMJ disorder) evaluated	Relevant findings
Tallents et al., 2002[19]	Case–control	345	Partially edentulous	Clinical and radiographical (MRI) assessment	Clinical evaluation of jaw pain, joint noise, and locking. radiographical evaluation of the TMJs for the presence or absence of disk displacement	Disk displacement was observed to be positively correlated with the absence of mandibular posterior teeth
Dulcić et al., 2003[39]	Cross-sectional	196 (male=68, female=128)	Partially edentulous	Clinical assessment	Clinical evaluation of the presence of one or more TMD symptoms - pain, crepitation, or clicking in the head and neck region	Regardless of sex, patients with more tooth loss in the supporting zones have a higher incidence and severity of TMD
Wang et al., 2009[12]	Cohort	741 (male=386, female=355)	Partially edentulous	Logistic regression analysis	Gender, age, the number of missing posterior teeth, and the number of quadrants with missing posterior teeth	The number of missing posterior teeth and the number of dental quadrants with missing posterior teeth both have an increased impact on TMD
Shetty, 2010[26]	Cross-sectional	100 (male=60, female=40)	Completely edentulous	Clinical assessment	Clinical evaluation of signs of joint sounds, joint tenderness, pain on mouth opening, muscle tenderness, deviation of the mandible on mouth opening, limitation during mouth opening, and referred pain	TMD symptoms were present in more than half of the asymptomatic patients. Additionally, 59% of the participants showed one or more TMD symptoms
Shet et al., 2013[25]	Cross-sectional	250 (male=99, female=151)	Partially edentulous	Clinical assessment	Joint sounds and joint tenderness	Subjects with greater tooth loss in the supporting zone have a higher incidence and severity of TMD and this can hasten the progression of degenerative joint disease
Falahi et al., 2016[24]	Case–control	200 (male=80, female=120)	Partially edentulous	Questionnaire-based and clinical assessment	Mouth opening, lateral excursions, deviations in the path of lateral excursions, presence or absence of clicking and crepitation, joint locking, condylar luxation, and pain in the TMJ and masticatory muscles	The number of occlusal support regions was found to be significantly correlated with the severity of TMD
Manchikalapudi and Polasani, 2017[54]	Case–control	140	Partially edentulous	Questionnaire-based and clinical assessment	Impaired mandibular movement, impaired or altered TMJ movement, muscle pain, joint pain, and pain in mandibular movements	While denture wearers displayed mild mandibular mobility restriction and mild pain during jaw motions, nondenture wearers displayed higher muscular soreness on palpation, clicking, and deviation of the jaw
Bertram et al., 2018[20]	Case–control (2 years)	210 (male=98, female=112)	Partially edentulous	Clinical and radiographic (CBCT) assessment	Radiographically evaluated for condylar morphology	A positive correlation was found between the degree of TMJ condylar erosion, the number of posterior teeth missing in each quadrant, and the bilateral position of posterior teeth missing
Chairunnisa and Sihombing, 2018[55]	Cross-sectional	100	Partially edentulous	Questionnaire-based and clinical assessment	Maximal mouth opening distance, TMDs function decline, and deviation, muscle pain, joint pain, and pain during mandibular movements	As the number of missing teeth increases, the incidence of TMDs also increases
Reshmi et al., 2018[21]	Cross-sectional	150	Partially edentulous	Questionnaire-based and clinical assessment	Limitations in movement, joint clicks, a feeling of tiredness or fatigue in the TMJ region, duration of symptoms, and the severity of symptoms	The prevalence of TMD among partially edentulous subjects was found to be low among the participants
Amin et al., 2019[22]	Cross-sectional	143 (male=78, female=65)	Partially edentulous	Clinical assessment	Facial pain, mouth opening, deviation, TMJ sounds, muscle tenderness	Signs of TMDs are more common in partially edentulous patients
Agustina et al., 2020[23]	Cross-sectional	113	Partially edentulous	Clinical assessment	Joint sounds (clicking, popping, and crepitation)	The degree of tooth loss is significantly correlated with TMJ clicking and crepitation
Zakir et al., 2020[27]	Cross-sectional	100	Completely edentulous	Clinical assessment	TMJ pain and sounds, mouth opening, and head, and neck muscles pain	During the first 5 years of edentulousness, TMJ problems were the most common

MRI: Magnetic resonance imaging, TMJ: Temporomandibular joint, TMDs: TMJ disorders, CBCT: Cone-beam computed tomography

DISCUSSION

The included studies’ data supported acceptance of the null hypothesis of no difference in terms of prevalence and severity of TMJ disorders between the partially and completely edentulous group as it was observed from the included studies that the development of TMDs is a multifactorial entity and that not only loss of occlusal support, but, occlusal disharmony, emotional stress, masticatory muscle fatigue, parafunctional oral habits, traumatic injuries, hormonal influences, articular changes within the joint and malfunction of structures adjacent to TMJ can cause TMJ dysfunction in partially/completely edentulous patients.[22,28-30] This can further lead to the development of symptoms such as persistent masticatory muscle discomfort that radiates to the head and neck region.[30]

The confirmation of the possibility of the presence of any TMD symptoms better relies on a positive clinical dynamic/static test outcome;[31,32] therefore, low to moderate biased studies in which TMJ disorders were diagnosed via clinical examinations were preferably included for qualitative synthesis, except for one study in which the link between a number of independent factors and a categorical dependent variable was examined using logistic regression analysis. In addition, it determines the likelihood of an occurrence by fitting data to a logistic curve.[33]

Although there are studies that have found a low correlation between occlusal factors and the development of TMDs,[34-36] the included studies in the present systematic review have shown a strong prevalence of TMD following tooth loss. This can be explained according to the fact that in partially edentate patients, tooth loss or tooth wear may affect the occlusion and condylar posture at TMJ. Losing a tooth also causes the remaining teeth that are opposite and adjacent to shift, which results in early contact in centric and eccentric movements. Temporomandibular disorders and pain dysfunction symptoms may be brought on by this change in condylar posture over time, which may also cause structural alterations to the TMJ surfaces.[37] The impact of condylar position and loss of posterior teeth on temporomandibular disorders is still debatable, and little is known about the impact of the loss of anterior teeth and condylar position based on the research that is now accessible.[37,38] Complete edentulism is characterized by retruded contact position and the absence of intercuspation. Because of this, when the jaw closes, the position of the condyle-fossa in the mandibular fossa may change.[1]

Most of the included studies[19,21,23,24-27,39] recorded joint sounds for clinical assessment of TMJ following tooth loss which can be explained by researches done by various authors, concluding that joint sounds (clicking followed by crepitation and popping) are the most common sound symptom that arises from TMD.[23,40,41] As a result of friction between the condyle and the disc’s posterior band, these articular noises are generated in TMJs that demonstrate disc displacement without reduction. Such a collision would make a single sound at the movement’s maximum amplitude.[42] Some researchers believe that clicking can be a pause in the meniscus’s forward gliding motion or it can also be related to sudden acceleration of condylar and internally displaced disc tissues.[43-46] According to others, clicks can also be attributed to fluid cavitation or can be found associated with a sudden movement of ligaments.[47,48] Crepitus is thought to be a symptom of osteoarthrosis, which is more common in patients who are edentulous, and other degenerative diseases of the articular surfaces, which are often brought on by aging.[46,49] According to Hwang et al. as indicators of anterior disc displacement with reduction and arthrosis, respectively, clicking and crepitation should be regarded as markers of morphological abnormalities.[50] However, according to a few authors, jaw sounds are common in the general/nonpatient population, and their clinical significance remains questionable; therefore, without discomfort or restricted jaw mobility, jaw sounds by themselves do not signify any TMJ issue.[42,51-53] Pain in the TMJ originates from the articular surfaces when the joint is overloaded. This can occur after tooth loss due to masticatory overloading. Mandibular movement immediately ceases when such pain is suddenly and unexpectedly felt (nociceptive reflex). However, over a due period, movement becomes limited and very deliberate (protective cocontraction).[10] Considering all these factors, apart from joint noises, all the included studies have assessed joint/muscle pain and tenderness, with few studies also assessing mandibular movements,[22,24,26,54,55] mouth opening,[22,24,26,27,55] and referred pain to head and neck region.[26,27,39]

The present study was limited by the inclusion of just a small number of studies examining the impact of tooth loss on TMJ in entirely edentulous patients. Furthermore, because there was a dearth of data, there was less research that linked radiographic analysis and clinical symptoms of TMDs. The same rationale prevented the inclusion of studies with large patient population and follow-ups. Future studies should include long-term follow-ups and a larger patient population. Studies correlating radiographs and clinical symptoms of TMDs following tooth loss are also required for a more precise outcome. More studies on the impact of TMJ after tooth loss in totally edentulous research to enable the scope of a meta-analysis should be undertaken to produce more precise information on this subject.

CONCLUSION

The following conclusions were drawn in accordance with the findings of this systematic review:

1. Effect of missing teeth on TMJ is always there and sometimes undergoes undiagnosed. This may be because these effects are frequently not clinically accompanied by pain. Although joint noises alone cannot be a determinant of TMD, other symptoms such as myofascial pain or any changes in mandibular movements should also be recorded for precise diagnosis

2. With an increase in the number of missing teeth, the severity of the negative impact on the TMJ also increases

3. In the case of partially edentulous patients, loss of posterior support has a more detrimental effect on TMJ than the loss of anterior

4. Being a multifactorial entity, complete loss of teeth alone cannot ensure the risk of the development of TMD. Other factors such as psychosomatic, physiological, anatomical, postural, and genetic should also be considered.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.