INTRODUCTION

Temporomandibular disorders (TMD) constitute a broad group of clinical problems involving the temporomandibular joint (TMJ), chewing muscles and associated orofacial structures, considered complex and of multifactorial origin¹,².

The importance of occlusion for the appearance of TMD is controversial and what was previously considered an etiological factor now has an almost irrelevant causal relationship, as there is no literature that supports the relationship that malocclusion causes TMD³,⁴,⁵.

Severe malocclusion can have a considerable impact on people’s physical and psychosocial well-being, mainly influencing self-esteem. Orthodontic treatment has been cited in various ways as a protective and detrimental factor in the etiology of TMD, however current literature does not support this influence⁶,⁷. In orthodontics, the first step in an effective interdisciplinary treatment plan for adult patients with a deep bite that is associated with an excessive curve of Spee in the lower arch and reverse curve in the upper arch is the correction of the occlusion plane. To do this, “bite turbos” are glued or an occlusal elevation is created as a way of altering the vertical dimension and making the correction⁸.

Temporary lifting of the bite in the anterior or posterior region with fixed devices, when well indicated, assists in orthodontic therapy: positively interfering with the efficiency of the treatment. The installation of occlusal lifts promotes the disocclusion of the arches, eliminating occlusal interferences, freeing and stimulating tooth movement⁹,¹⁰.

The objective of this study was to evaluate TMD symptoms in patients who used occlusal lifts during orthodontic treatment, thus investigating the interference of the installation of its temporary installation and comparing it to a control group.

METHODS

The present study was submitted and approved by the Research Ethics Committee Involving Human Beings from the São Leopoldo Mandic Dental Research Center, Campinas, Brazil, under opinion no. 5,055,851.

This research is cross-sectional, observational and quantitative in nature. A sample of 40 patients was evaluated according to the methodology of reference study¹¹. The individuals were selected according to the indication of orthodontic mechanics using occlusal lifting. The patients were treated from the Vale do Rio Verde University Center (UninCor) Orthodontics Specialization Course Clinic, Belo Horizonte, Brazil.

The inclusion criteria were: good general and oral health (absence of cavities and other oral diseases); absence of TMD symptoms; patients with an indication for orthodontic treatment with a fixed appliance using occlusal lifting, who required overbite and curve of Spee correction; patients with all permanent teeth except third molars; aged between 15 and 35 years, of both genders; patients who agreed to participate in the study after reading and signing the Free Informed Consent Term (FICT). Exclusion criteria were patients with psychosocial markers assessed using the WISE clinicians questionnaire; individuals constantly using analgesics and anti-inflammatories.

Before the start of the study, patients underwent a clinical examination and complete anamnesis, which predicted the absence of TMD symptoms and the use of drugs to control pain. Those who reported using analgesic and anti-inflammatory drugs or signs and symptoms of TMD were excluded from the study. The control group also consisted of 40 patients of both genders who required orthodontic treatment, but without indication of occlu-sal lifting. The evaluation for both groups was carried out at times T(0) before the installation of the fixed orthodontic appliance; T(1) 24 hours after installation of the occlusal elevator; T(2) 30 days after installation of the occlusal elevator.

Study design

The researcher installed upper and lower fixed orthodontic appliances on the patients. After 30 days, they underwent installation of occlusal lifts on the occlusal surface of the upper first molars (16 and 26), prepared after conditioning with 37% phosphoric acid for 30 seconds, abundant washing and drying. Ortho Bite resin (FGM-Joinville, Brazil) was then applied, which is a light-polymerizable, self-adhesive, self-leveling composite with a high level of surface hardness indicated for temporary tooth disocclusion during orthodontic treatments. It also has dyes to make the product easier to see during application and removal. After the light cure was applied for 20s. The height of the lifts will be the minimum necessary to promote the disocclusion of the teeth.

Patients were evaluated in three different times, where the “Diagnostic Criteria” (DC/TMD), and the “WISE Clinicians” (Web Based Interdisciplinary Symptom Evaluation) symptom questionnaires were applied to analyze the involvement of psychosocial factors: T0) before the installation of the fixed orthodontic appliance; T1) 24 hours after installation of the occlusal lift; T2) 30 days after installation of the occlusal lift.

Statistical analysis

The data were tabulated in Microsoft Office Excel® software and exported to the GraphPad Prism 8.4 program for statistical analysis. Data was expressed as simple frequency and percentage. Data normality was tested using the Kolmogorov-Smirnov and Shapiro-Wilk tests. For comparative data analysis, the Kruskal-Wallis and binomial tests were used, while for correlation analysis, the McNemar and multiple logistic regression tests were used. The confidence interval adopted was 95% and p<0.05 (5%) was considered statistically significant.

RESULTS

A total of 40 participants were evaluated. Participants were aged between 15 and 45 years, with an average of 24.03±7.91 years. A total of 35.0% of participants were female (n=14) and 65.0% male (n=26), no significant quantitative difference was identified for this variable (p>0.05, binomial test). Regarding the age of the participants, the majority were between 15 and 24 years old (n=23), with a significant quantitative difference between this part of the population when compared to the others (Table 1). The normality of data distribution was verified, revealing a lack of normality for the variables evaluated in this study.

Within 24 hours after applying the resin, 42.5% of study participants reported muscle pain (n=17). 30 days after the procedure, pain was detected in 12 participants (30%) (Table 2).

When analyzing participants stratified by the presence of pain after 24 hours and after 30 days, it became clear that the duration of exposure to occlusal lifting does not present a significant correlation with the onset of pain (p=0.3827, McNemar’s test). Also observed was the occurrence of 21 discordant pairs, 13 (61.905%) that presented pain after 24 hours, but not after 30 days, and 8 (38.095%) that presented pain after 30 days, but not after 24 hours (Table 3).

Of the 14 female participants, 9 (64.3%) reported pain in the first 24 hours, and 3 after 30 days of the procedure. As for male participants, 8 (30.8%) had pain in the first 24 hours, a number that increased to 9 (34.6%) in the evaluation after 30 days (Table 4).

Of the female participants, 14.3% had pain in the two periods studied, while 28.6% had no pain during the study. It is also observed that one participant who did not experience pain after 24 hours started to experience pain after 30 days, and that 7 of those who had pain in the first 24 hours did not experience analgesia after 30 days. As for male participants, 8 reported pain after 24 hours, but 18 said they had no pain at all. Still among men, 6 participants who had reported pain in the first 24 hours did not have pain when reassessed after 30 days, while 7 who had not reported pain in the first 24 hours had pain after 30 days.

No significant correlation was found when evaluating the correlation between the presence of pain in the two periods studied and the gender of the participants (p=0.7869, Multiple logistic regression).

DISCUSSION

This study aimed to evaluate TMD symptoms in patients undergoing orthodontic treatment that required the use of occlusal elevation.

A total of 40 patients of both genders and aged between 15 and 35 years were selected, all with an indication for orthodontic treatment. In the sample, a total of 65% (26) were male and 35% (14) were female, with an average age between 21.58 and 26.48 years. Pain assessment was carried out at three different moments: the first before the installation of the occlusal lift, the second 24 hours after placement of the occlusal lift, and the third moment 30 days after the installation of the occlusal lift.

In a more detailed analysis of this study, it can be seen that 10% of the patients had pain at both moments and 37.50% did not have pain at any point during the analysis, and 32.50% of the patients in the sample had pain in the first At the time of assessment, they no longer presented pain in the second moment, 30 days after installing the occlusal lift. This is in line with study¹² who argue that the application of occlusal interference increases the risk of developing TMD, but that the symptoms are transient. However, the present study did not monitor pain intensity on a visual analog scale as study¹¹ did, which should be a focus for future work.

Separating the patients in this study sample by gender, 50% of women who presented pain in the first moment of the evaluation did not manifest pain in the second moment after 30 days. For males, 23% of men who had pain at first no longer expressed complaints at the end of the study. This result agrees with studies that show women are more predisposed to the onset of pain than men¹³,¹⁴. However, it was observed that the percentage of remission of painful symptoms at the end of the sample was lower in men, requiring further studies to verify this disparity.

Occlusion, as well as orthodontics, has already been cited as a triggering factor for TMD¹⁵. However, currently, studies point in the opposite direction, treating occlusal changes with less relevant factors in the etiology of TMD⁴,⁶,⁷, in a similar way to the results of the present study reinforce the non-influence of changes in the occlusal pattern on the onset of TMD pain, given the presence of transient symptoms and remission within a short period of time. Faced with the various controversies about the etiology of TMD, many professionals have difficulty diagnosing and consequently treating patients, generating insecurity and ineffective treatment. The lack of sample heterogeneity is a limiting factor in this study, directly impacting the findings, as well as the impossibility of comparison with other studies with different methodologies. Based on the above, this research leads to the conclusion that when using occlusal lifting, there is no significant correspondence between manifesting TMD after 24 hours and 30 days after installing the occlusal lifting. Therefore, if any prolonged painful symptom occurs related to the installation of the occlusal lift as an auxiliary mechanic in orthodontic treatment, the dentist must investigate the possible presence of other etiological factors for the emergence of temporomandibular dysfunction.

CONCLUSION

It can be concluded that occlusal lifting was not significant in terms of pain in most patients and when compared to the control group. Thus, it is suggested that the interference caused by the lifting does not present symptoms that could affect the continuation and completion of orthodontic treatment.

REFERENCES

Edited by

Publication Dates

History