Dr. Kamanksha Mhatre1, Dr. Saloni Mistry2 , and Dr. Parmeet Banga3
1Post-graduate Student
2Professor and Head of Department,
3Reader,
Department of Prosthodontics, Crown & Bridge.,
Y.M.T Dental College, Navi Mumbai
ABSTRACT
Background: Occlusal equilibration is important in clinical practice and its implication has been neglected in curriculum. To practice occlusal equilibration techniques the clinician needs to observe a number of accurate steps and conventional and digital aids being used for clinical application.
Objectives: This survey was undertaken to assess and evaluate awareness, knowledge and attitude of prosthodontist towards different conventional and digitalized occlusal equilibration techniques used in fixed prosthodontics.
Materials and Methods: An online survey was conducted amongst the prosthodontist and post graduate students in prosthodontics specialty across India. It was in the form of questionnaire consisting of 23 open and multiple-choice questions concerning the awareness and use of occlusal equilibration techniques by prosthodontist of India. The URL of google doc form questionnaire were shared via internet to prosthodontist which were postgraduate students, academician and practitioner, to obtain response of 99 which was a predetermined sample size. Data was subjected to statistical analysis using Statistical package for social sciences (SPSS v 26.0, IBM). For all the statistical tests, p<0.05 was considered to be statistically significant, keeping α error at 5% and β error at 20%, thus giving a power to the study as 80%.
Results and interpretation: This survey was focused on evaluating the awareness about occlusal equilibration techniques ranging from conventional to the newer digital aids. Though the articulating paper still remains the gold standard, the appropriate use with proper thickness and knowledge at what stage is performed is of great importance. More knowledge about contemporary digital methods is necessary for its clinical use.
Keywords: occlusal equilibration, muscle deprogrammer, T-scan, Occlusense.
Citations: Mhatre K, Mistry S, Banga P. Occlusal equilibration: Are we going the right way? -A survey. J Prosthodont Dent Mater 2022;3(1):39-49.
INTRODUCTION
A goal of optimal dentistry is the long-term stability of all components of the masticatory system: teeth, periodontium, muscles of mastication, and temporomandibular joints (TMJs). There is extensive literature and an anatomic-biomechanical rationale supporting a therapeutic occlusion as integral to the diagnosis, treatment planning and restorative dentistry.
Full mouth rehabilitation presents the clinician with many challenges and pitfalls. One of the most demanding aspects of FMR involves the development of sufficient restorative space with optimum occlusion. While simultaneously fulfilling esthetic and functional parameter to long term success.
Occlusal equilibration is one of the key factors for maintaining the harmony of stomatognathic system. Emphasis must be placed on recording of muscle deprogramming as well as an occlusal prematurities preventing condylar seating into centric relation position.1 Occlusal equilibration is important in prosthodontic pretreatment and should not be only used for selected cases but for all prosthodontic rehabilitation cases. There are variety of muscle deprogrammer have been used in practice with different range of results.
Conventional methods include articulating paper with varying thickness. Rapid advancements in technology have been occurred in these modern digital era and devices are used to evaluate and analyze occlusion such as T-scan and occlusense and gained popularity amongst practitioners. T-scan and Occlusense are an objective assessment tool used to evaluate the occlusion of a patient. Unlike articulating paper, which can only determine location, T-Scan can identify both force and timing, two of the most fundamental parameters for measuring occlusion. Therefore, this study was conducted to assess and evaluate awareness, knowledge and attitude of prosthodontist towards occlusal equilibration techniques as well as need of it to be used in full mouth rehabilitation and other fixed dental prosthesis cases.
MATERIAL AND METHODS:
Study setting and participants:
This questionnaire-based cross-sectional study was conducted over a period of 1 month between February 1 and March 5, 2021. The participants consisted of post graduate students, practicing dentists and academician exclusively from department of prosthodontics from various parts of India with varying experience, age and sex. The study participants were approached by the principal investigator.
Data collection:
A structured, self-explanatory questionnaire was created in English on the Google Forms platform. It consisted of a brief introduction to the study, followed by 2 sections. Section I collected the demographic data, and section II consisted of 23 open- and closed-ended questions regarding the participants’ knowledge, attitude and practice with occlusal equilibration techniques used in fixed dental prosthesis. The study participants were approached by the principal investigator via personal connections and the Internet/e-based technologies (e.g., online platforms and e-mail). According to their responses and feedback, the following changes were made: – the questions were divided into 2 sections – section I consisted of questions related to the sociodemographic data, while section II consisted of questions related knowledge regarding occlusal equilibration, muscle deprogrammer, articulating paper and recent advancement in relation to occlusal analysis – multiple option checkboxes were added wherever necessary. The questionnaire was then sent to the study participants and their responses were kept confidential. Timely reminders were sent as well. Participation was completely voluntary and all the participants could opt out of the study by not completing the questionnaire.
A structured, self-explanatory questionnaire was created in English on the Google Forms platform. It consisted of a brief introduction to the study, followed by 2 sections. Section I collected the demographic data, and section II consisted of 23 open- and closed-ended questions regarding the participants’ knowledge, attitude and practice with occlusal equilibration techniques used in fixed dental prosthesis. The study participants were approached by the principal investigator via personal connections and the Internet/e-based technologies (e.g., online platforms and e-mail). According to their responses and feedback, the following changes were made: – the questions were divided into 2 sections – section I consisted of questions related to the sociodemographic data, while section II consisted of questions related knowledge regarding occlusal equilibration, muscle deprogrammer, articulating paper and recent advancement in relation to occlusal analysis – multiple option checkboxes were added wherever necessary. The questionnaire was then sent to the study participants and their responses were kept confidential. Timely reminders were sent as well. Participation was completely voluntary and all the participants could opt out of the study by not completing the questionnaire.
Statistical analysis: :
The data was compiled in a Microsoft Office Excel spreadsheet (v. 2019; Microsoft Corporation, Redmond, USA). The data was subjected to the statistical analysis with the use of the IBM SPSS Statistics for Windows software, v. 26.0 (IBM Corp., Armonk, USA). Descriptive statistics like number and percentage (n (%)) were used for categorical data. Numerical data was expressed as mean and standard deviation (M ±SD). The comparison of frequencies for the categories of variables between the groups was made using the χ2 test. For all statistical tests, p < 0.05 was considered to be statistically significant, keeping α error at 5% and β error at 20%, thus giving power to the study of 80%.
Results:
This survey had a sample size of 99 prosthodontist who completed the questionnaire with majority of population of postgraduate students (42) followed by practitioner (22) and academician (20). Half of the participants were between 20 and 30 years of age, with 52 (54.2%) having worked less than 5 years and 32(33.3%) having experience for more than 10 years.
Approximately all of the participants were aware about the occlusal equilibration techniques to be used in full mouth rehabilitation. Among the respondent they have knowledge about the purpose of occlusal equilibration technique and believed that it is simultaneous contact of all posterior teeth with forces directed at long axis of those teeth (26%).
Sign of stable occlusion was common stable stops on all teeth in MIP and for unstable occlusion was excessive wear which was considered the most accepted among the respondents.
Mutually protected occlusion (62.5%) was most accepted occlusion scheme and occlusion equilibration was carried out in full mouth rehabilitation cases at preliminary recontouring at diagnostic stage (34.4%) and Provisional restoration stage (17.7%) but academician preferred to perform at bisque trial stage at upright position.
There are different muscle deprogrammer available out of which Lucia jig (34.4%) is most common type of muscle deprogrammer used among the post graduate students. The knowledge and awareness about Kois deprogrammer (60.4%) is more but the clinical application is less among the post graduate students and clinician.
There are two types equilibration techniques namely mechanical and digital equilibration. Mechanical aids consist of articulating papers with different variety of thickness available. The most common type of articulating paper used in full mouth rehabilitation cases is 40-micron thickness followed by 8-12 micron thickness.
Awareness and knowledge of T-scan (91.7%) is comparatively is to greater extent than Occlusense (47.9%) among prosthodontist. However, they have been rarely used in clinical scenario by prosthodontists.
Questionnaire used in survey with the results in tabular format:
| Question | Answers | Results | % |
|---|---|---|---|
| 1. Do you prefer using occlusal equilibration techniques in fixed prosthesis? OR Are you aware of occlusal equilibration techniques used in Full Mouth Rehabilitation (FMR)? | I. Yes | 88 | 91.7 |
| II. No | 3 | 3.1 | |
| III. Not sure | 5 | 5.2 | 2. According to you, what is the purpose of occlusal equilibration? | I. CR = MIP | 18 | 18.8 |
| II. Simultaneous contact of all posterior teeth with forces directed at long axis of those teeth | 25 | 26.0 | |
| III. Muscle equilibration | 9 | 9.4 | |
| IV. To establish patient original vertical dimension | 5 | 5.2 | |
| V. All of the above | 0 | 0 | 3. Which signs do you look for stable occlusion? | I. Stable stops on all teeth in MIP | 23 | 24.0 |
| II. Disclusion of posterior teeth in protrusive movements | 11 | 11.5 | |
| III. Disclusion of all posterior teeth on working side at lateral excursion | 2 | 2.1 | |
| IV. Non interferences of all posterior teeth on working side at lateral excursion | 8 | 8.3 | |
| V. All of the above | 0 | 0 | 4. Which signs do you look for unstable occlusion? | I. Excessive wear | 25 | 26.0 |
| II. Hypermobility of one or more teeth | 7 | 7.3 | |
| III. Horizontal drifting | 3 | 3.1 | |
| IV. Intrusion | 0 | 0 | |
| V. Supraeruption | 3 | 3.1 | |
| VI. All of the above | 0 | 0 | 5. Do you think occlusal disharmony will have affect the health of TMJ? | I. Yes | 6 | 6.3 |
| II. No | 90 | 93.8 | 6. Which occlusal scheme do you prefer for full mouth rehabilitation? | I. Group function | 14 | 14.6 |
| II. Mutually protected occlusion | 60 | 62.5 | |
| III. Balanced occlusion | 8 | 8.3 | 7. Have you used occlusal equilibration techniques for following fixed dental prosthesis? | I. Single crown | 6 | 6.3 |
| II. 3 unit FDP | 1 | 1.0 | |
| III. More than 3 unit FDP | 8 | 8.3 | |
| IV. FMR | 30 | 31.3 | 8. In your clinical practice, at what stage you will like to perform occlusal equilibration/ adjustment? | I. Preliminary recontouring at diagnostic stage | 33 | 34.4 |
| II. Provisional restoration stage | 17 | 17.7 | |
| III. Bisque trial stage | 9 | 9.4 | |
| IV. After final cementation | 0 | 0 | 9. Which patient position will you prefer for occlusal equilibration? | I. Supine | 15 | 15.6 |
| II. 45 degrees | 15 | 15.6 | |
| III. Upright | 62 | 64.6 | |
| IV. Position won’t affect | 4 | 4.2 | 10. Does chewing cycle pattern and envelope of motion have effect on restoration? | I. Yes | 99 | 100 |
| II. No | 0 | 0 | 11. Do you think deprogrammer will aid in occlusal equilibration? | I. Always | 41 | 42.7 |
| II. Never | 4 | 4.2 | |
| III. Sometimes | 51 | 53.1 | 12. What are the different deprogrammers you have used in your practice? | I. Lucia jig | 34 | 35.4 |
| II. Leaf gauge | 6 | 6.3 | |
| III. Kois deprogrammer | 4 | 4.2 | |
| IV. All of the above | 0 | 0 | 13. Are you aware about Kois deprogrammer? | I. Yes | 58 | 60.4 |
| II. No | 37 | 38.5 | |
| III. Not sure | 1 | 1.0 | 14. Have you ever used Kois deprogrammer in your practice? | I. Yes | 16 | 16.7 |
| II. No | 80 | 83.3 | 15. What is your choice of articulator? | I. Hinge type | 1 | 1.0 |
| II. Semi adjustable | 87 | 90.6 | |
| III. Fully adjustable | 8 | 8.3 | 16. What are the different thicknesses of articulating paper you have used in your practice? | I. 200 micron | 6 | 6.3 |
| II. 40 micron | 17 | 17.7 | |
| III. 8-12 micron | 12 | 12.5 | |
| IV. shimstock | 2 | 2.1 | 17. Are you aware of Artifol? | I. Yes | 56 | 58.3 |
| II. No | 40 | 41.7 | 18. Have you use occlusal spray for occlusal correction in your clinical practice? | I. Yes | 31 | 32.3 |
| II. No | 65 | 67.7 | 19. Do you prefer mechanical equilibration techniques or digital? | I. Mechanical | 49 | 51.0 |
| II. Digital | 0 | 0 | |
| III. Both | 47 | 49.0 | 20. Are you aware of T scan? | I. Yes | 88 | 91.7 |
| II. No | 8 | 8.3 | 21. Have you used T scan? | I. Yes | 16 | 16.7 |
| II. No | 80 | 83.3 | 22. In which cases T scan is advocated? | I. Facial pain (MPDS) | 1 | 1.0 |
| II. Occlusal correction in FMR cases | 16 | 16.7 | |
| III. Postural abnormalities affecting spine | 0 | 0 | |
| IV. TMD | 9 | 9.4 | |
| V. All of the above | 0 | 0 | 23. Are you aware of occlusense? | I. Yes | 46 | 47.9 |
| II. No | 50 | 52.1 | 24.Have you used occlusence? | I. Yes | 11 | 11.5 |
| II. No | 85 | 88.5 | 25.Do you think digital occlusal equilibration techniques are more accurate and sensitive than mechanical methods? | I. Yes | 75 | 78.1 |
| II. No | 21 | 21.9 |
DISCUSSION:
1The mandibular neuromuscular complex has a strong adaptive capacity which allows functioning and protection of the masticatory system. Deflective occlusal contacts will induce an irritable condition into the neuromuscular system which will be continuously reinforced with each closure through proprioceptive feedback. This conditioned state (engram) may induce changes at the level of any components of the masticatory system: teeth, muscles, periodontium, gingival mucosa and temporomandibular joints. Occlusal dysfunctions can be cured by using deprogramming methods.3
2) Occlusal equilibration is carried out to produce a specific occlusal scheme, generally in severely debilitated dentition, requiring extensive restorative treatment. Occlusal equilibration may require extensive tooth modification to develop the prescribed occlusal scheme. Those features may be achieved with fixed restorative procedures.4
3) Occlusal equilibration is a therapeutical abrasive technique that can remove or correct occlusal interferences using the selective grinding of the cuspal slopes or ridges of the teeth interfered with normal functional occlusal paths. This method of correcting occlusion can be applied at the occlusal surface of natural teeth or prosthetic reconstructions using occlusal therapeutic grinding techniques. 4
4)Occlusal equilibration is indicated because it removes the disagreement and occlusal and temporomandibular joint dysfunctions of the TMJ dysfunction syndrome. Fully functional maxillary and mandibular dental arches have the role to protect a harmonious occlusal function against parafunctional activity of neuromuscular system: pain around the temporomandibular joints or the masticatory muscles with or without clicking, inability to fully open the mouth, head and neck aches.5
5) There is sequence of occlusal equilibration which include preliminary recontouring, elimination of all centric relation occlusal interferences, elimination of all excursive interferences, re-examination of all centric relation occlusion and finally smoothening of all corrected surfaces expect centric stops.6 Results we got from the survey were statistically significant with higher response for preliminary recontouring at diagnostic stage & provisional restoration stage by postgraduate and among practitioner it is performed at bisque trial stage (P value = 0.007).
6) There are different deprogrammers are used in prosthodontics like Lucia jig leaf gauge and anterior deprogrammer while performing full mouth rehabilitation.7 Statistically significant results were found with higher frequency response for Lucia jig with post graduate students (P value = 0.027).
7)Occlusal equilibration techniques are widely classified into conventional and digital method. The most commonly used is the conventional method by the means of an articulating paper. There are different papers to precisely analyze tooth contact relations in static and dynamic occlusion ranging from 100 micron to 8-12 micron. 100 micron is exclusively used for complete denture patients and 40 micron and shim stock articulating paper are used in fixed prosthodontics. Most of participants preferred 40 micron size articulating paper in fixed prosthodontics (P value = 0.113).
8) The recent advancement in the field of occlusal equilibration is the use of t-scan and occlusense for accurate and precise digital assessment of occlusion. T scan gives time vs force graph. Over the years T-Scan’s presents different software and hardware versions which were tested, criticized, and improved. According to current status of digital technology T-scan has revolunized the occlusal equilibration techniques but it does not present itself as cost effective option.8,9 Greatest awareness about T-scan is seen among academician and post graduate students (P value = 0.03). Contradictory to their awareness usage is very less and most of the participants prefers T-scan while doing occlusal corrections in FMR cases.
9) Awareness and knowledge of Occlusense is more amongst practitioner and post graduate student (P value = 0.028) whereas the usage (P value = 0.657) is less significant. The intaglio surfaces of the occlusense sensor are coated with red articulating ink, to mark the teeth at the same time a digital data recording is being made. The sensor thickness is about 100 microns for T-Scan and 60 microns for occlusense. However, occlusense is cost effective as compared to T-Scan. Presently, there are no durability, repeatability, or accuracy studies about the occlusense sensor, as it has not yet to date, been tested for its attributes or its capabilities in any published study.
9)Literature speaks that size of articulating paper marking is unreliable indicator when compared to digital method for occlusal force analysis.10,11 Documented literature which compare two digital equipment one with high tech t scan vs recently introduced occlusense, stated that two devices are vastly different in features though t scan gives a quantitative occlusal analysis but Occlusense gave both qualitative and quantitative results.12 In both the devices knowledge and awareness is more but their use is limited.
CONCLUSION:
Post graduate students perform occlusal equilibration at diagnostic stage and provisional restoration stage.
Among post graduate students’ awareness and usage of Lucia jig as anterior deprogrammer is more significant.
Awareness of Kois deprogrammer is more significant in academician and PG students but its use is limited.
Prosthodontist were aware about the different thickness of articulating paper however the discretion in use of articulating paper and their thickness and interpretation are non-confirmatory.
Awareness of T scan is more in PG students.
Awareness of Occlusense is more in post graduate and practitioner and usage of occlusense is more in practitioner.
This survey was focused on evaluating the awareness about occlusal equilibration techniques ranging from conventional to the newer digital aids. Though the articulating paper still remains the gold standard, the appropriate use with proper thickness and knowledge at what stage is performed is of great importance. More knowledge about contemporary digital methods is necessary for its clinical use.
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