|Year : 2020 | Volume
| Issue : 3 | Page : 139-143
Comparative evaluation of the masticatory efficiency of complete dentures with bio-engineered teeth and conventional denture teeth using electromyography – A randomised crossover clinical study
Ninad N Bhatt1, Ronak Patel1, Jalak Patel1, Tamanna Chhabra2, Rajesh Sethuraman2, Sarvesh Patel1
1 Private Practitioner, Vadodara, India
2 Department of Prosthodontics and Crown and Bridge, K. M. Shah Dental College and Hospital, Sumandeep Vidyapeeth, Waghodia, Gujarat, India
|Date of Submission||26-Apr-2020|
|Date of Acceptance||18-Aug-2020|
|Date of Web Publication||22-Sep-2020|
Ninad N Bhatt
Department of Prosthodontics and Crown and Bridge, K. M. Shah Dental College and Hospital, Sumandeep Vidyapeeth, Piparia, Waghodia - 391 760, Gujarat
Source of Support: None, Conflict of Interest: None
Background and Objective: Resorption of residual ridge is common problem related to edentulous mandible. One of the main causes of resorption of denture-supporting structures is traumatic or excessive force transmitted through the prosthesis. The resilient-layer and occlusal-reactive dentures are clinical attempts developed for impact reduction and distribution of the masticatory load to the edentulous ridge. Bio-engineered posterior denture teeth which was used in this study have resilient silicone material lining which lead to cushioning effect and reduced the force transmitted to the basal bone. This study was done to assess and compare the masticatory efficiency of complete dentures with bio-engineered teeth and conventional denture teeth using electromyography (EMG) analysis. Methodology: The present study was conducted on 09 completely edentulous patients who reported to the department of prosthodontics and crown and bridge. Two Groups Were Made: Group A - conventional denture and Group B - denture with bio-engineered teeth. All the patients were randomly allotted to Group A or B using random allocation software, after 3 months EMG recording was done, and then, all the patients were provided another set of denture, other than the group in which they had allocated previously. EMG recording was done again after 3 months of providing the denture of other group. Results: Paired t-test showed no statistically significant difference in EMG reading of left masseter (P = 0.514), right masseter (P = 0.545), left temporalis (P = 0.954), and right temporalis (0.944) between both the groups. Conclusion: Both the dentures did not show any statistically significant difference in terms of EMG activity, which indicates that the masticatory efficiency of bio-engineered teeth denture is comparable to that of conventional denture.
Keywords: Bio-engineered teeth, complete denture, electromyography analysis, masticatory efficiency, periodontal ligament analogue
|How to cite this article:|
Bhatt NN, Patel R, Patel J, Chhabra T, Sethuraman R, Patel S. Comparative evaluation of the masticatory efficiency of complete dentures with bio-engineered teeth and conventional denture teeth using electromyography – A randomised crossover clinical study. Adv Hum Biol 2020;10:139-43
|How to cite this URL:|
Bhatt NN, Patel R, Patel J, Chhabra T, Sethuraman R, Patel S. Comparative evaluation of the masticatory efficiency of complete dentures with bio-engineered teeth and conventional denture teeth using electromyography – A randomised crossover clinical study. Adv Hum Biol [serial online] 2020 [cited 2021 Apr 17];10:139-43. Available from: https://www.aihbonline.com/text.asp?2020/10/3/139/295827
| Introduction|| |
Resorption of residual ridge is common problem related to edentulous mandible, especially in denture wearer. The prevention of further deterioration of the health of the available tissues that have already been marred by the loss of the teeth has always been the primary objective of any prosthodontic treatment. The edentulous alveolar ridge is often called upon to support the complete dentures, thus making it perform a function it is not primarily intended for.
The natural tooth moves in its socket by means of periodontal fibre, which are elastic, so as to accommodate the stresses developed during chewing. Whereas in the artificial dentures stresses are transferred directly to the bone resulting in bone resorption and destruction. These forces are from two directions: one is during mastication which is mainly vertical and other one is during parafunction which is frequently horizontal as well as vertical. The horizontal forces are more destructive and lead to resorption of the bone.
Attempts were made to reduce the load on the ridge through several ways: (I) using tissue conditioner or soft liner (II) liquid- or gel-supported denture and (III) by modifying the denture teeth. As soft liners lose their plastic properties over a period of time, it can be temporary provision only. While liquid-supported or gel-supported dentures have disadvantages of leakage of liquid, technique sensitivity and require frequent repair.
Modification of denture teeth was attempted by Athur Nutter Brown in 1942 by using a compressible disc placed in between a bar type of attachment which fits in the hole made in tooth. Wasserman in 1967 also attempted to fabricate similar teeth whereby pressures applied to the tooth become transmitted via plunger and fluid to the walls of chamber which contains them. However, this designs require special small mechanical parts, also the mechanism is very much complex. Therefore, here a novel and simple technique to fabricate bio-engineered teeth with a compensatory ligament analogue is used.
Various methods have been used for testing masticatory efficiency. Those are: ultrasonography, photo colorimetry, direct method-chewing method known as sieve method and electromyography (EMG). Surface EMG measures muscle activity non-invasively using surface electrodes placed on the skin overlying the muscle. It is widely used in experimental analyses of the masticatory system.
The present study was done to compare the masticatory efficiency of dentures with bio-engineered teeth with conventional denture teeth by performing the EMG analysis of masseter and temporalis muscle. The null hypothesis was that no difference in masticatory efficiency would be found for dentures with bio-engineered teeth and conventional denture.
| Methodology|| |
This study was conducted in the department of prosthodontics and crown and bridge, after obtaining permission from the Institutional Ethics Committee. Pilot study with four samples was done, and sample size was calculated. Minimum sample required were eight patients (8 × 2 = 16 dentures) with 95% confidence interval and 80% power. The present study was done on nine completely edentulous patients, in which EMG analysis of complete denture fabricated using normal teeth and bio-engineered teeth was compared. Patients were explained about the study through subject information sheet, and informed consent was obtained. Basic information of the patient and the record of the procedure were maintained throughout the study.
Inclusion and exclusion criteria: Completely edentulous patients having adequate inter ridge distance (16–20 mm) and residual ridge with Class-2 or Class-3 ridge height were included in the study. Patients with a history of temporomandibular disorder, oral submucous fibrosis, neuralgia or any other neurological and neuromuscular disorders were excluded from the study.
Maxillary and mandibular primary and secondary impressions were taken as per the conventional complete denture procedures following the principles of clinical procedures given by Boucher. Two casts were duplicated from the master cast by using agar-agar. The duplicated master casts were used to fabricate the denture. Using conventional acrylic denture, teeth dentures were fabricated for Group A. For Group B, bio-engineered teeth were used for fabricating dentures.
Fabrication of bio-engineered teeth
Step 1: A hole was made of 1 mm depth in the centre of ridge lap area of premolar and molar teeth, 1 mm deep reduction of the axial surface of 2 mm from the ridge lap area for lingual and proximal surfaces and 2 mm for buccal surface using straight fissure bur (SSW hp 702) [Figure 1].
Step 2: 5–6 mm long NiTi orthodontic open coil spring (Optima, Desire) was secured using auto-polymerising resin such that 1 mm of spring embeds in the hole made in ridge lap area [Figure 2].
Step 3: Adapt 2-mm thick baseplate wax over ridge lap area including the spring and also cover the reduced axial surfaces to give contours previously present [Figure 3].
Step 4: Prepare a mould by flasking and on dewaxing a space of 2 mm on ridge lap area and 1 mm on axial surface was present. A silicone adhesive A-330-G platinum primer (Factor II; AZ, USA) was applied on the surface of tooth and silicon material (Cosmesil M511, Principality Medical Ltd., UK) was packed and left at the room temperature for curing [Figure 4].
Step 5: After curing of silicone material, deflasking and finishing using silicone finishing bur was done, and 2 mm of the NiTi spring was exposed [Figure 5].
These bio-engineered teeth were arranged for the trial denture. All the patients were randomly allocated to Group A (Conventional denture) or Group B (denture with bio-engineered teeth) using random allocation software. After 3 months, EMG recording was done, and then, all patients were provided with denture of the group other than was allocated previously. EMG recording was done again after 3 months after providing the denture of other group. Blinding of patients and EMG evaluator was done. EMG surface electrodes were attached to the right masseter, and patient was asked to chew the 10 mg of peanuts. Same procedure was repeated with left masseter, left and right temporalis and peak to peak value from the EMG was recorded.
| Results|| |
[Table 1] shows the summary statistics and results of paired t-test of both groups. The mean EMG value for masseter left and right is more for Group A than Group B, while EMG value for temporalis left and right is less for Group A than Group B.
|Table 1: Summary of descriptive statistics and inferential statistics for both the groups|
Click here to view
[Graph 1] shows the result of mean EMG value that there is no significant difference between the means of the groups.
| Discussion|| |
In prosthodontics while restoring function, an attempt is made to replicate the natural form of anatomical structure that is lost. Most attempts made for denture teeth have been on occlusal anatomy. Very little consideration has been given in literature for the replication of periodontal ligament (PDL) in denture teeth primarily as they lack the root form. In natural dentition, PDL is the primary mechanism to absorb traumatic forces and pathologic occlusal load to the bone. In the long run, by the virtue of proprioception, the PDL filters most pathological forces from causing trauma to the bone. This primary mechanism is absent in the complete denture system. The alveolar bone is called upon to perform a function of supporting denture on slippery mucosa, a function that is not primarily indicated by the nature for alveolar bone. Further, the effect of lateral forces is detrimental to the alveolar bone that develops during eccentric movements. For ages attempts to alleviate or reduce the lateral loads from being traumatic to the bone have been made. In the bargain teeth, anatomy have been modified from being anatomic to semi-anatomic to non-anatomic, which is the major mechanism to reduce eccentric stress on bone. However, this modification resulted in reduced masticatory efficiency, thus affecting overall oral health related quality of life in patients with complete denture. In this study, an effort has been made to fabricate cushioned teeth that would compensate for lost PDL.
The bioengineered teeth fabricated had an anatomic occlusal form with a resiliency of the silicon based liner of 0.06 mm/N force and with using 39 N as average chewing force (range 26–43 N) for denture wearers, the thickness of compressible silicone layer to resist vertical force should be around (0.06 × 39≈) 2 mm which was used in this case. However, no literature found on average lateral force exerted on denture.
The NiTi open coil spring was used here for anchoring the tooth to the denture base. It exerts 0.5 N force per millimetre compression, and it has 2 mm length between tooth and denture base which virtually remain passive. Hence, patients with good inter ridge distance were selected for the current study. For better bonding of silicone to acrylic, surface treatment of teeth with methyl methacrylate for 180 s and A330G primer was used.
Balanced occlusion improves the stability and reduces the lateral forces. Compressibility of the teeth also helps in improving the balanced occlusion by adjusting to minor lateral imperfection, if any. It was hypothesised that the resiliency of teeth may reduce the masticatory efficiency of dentures and hence an EMG analysis was performed. EMG is a reliable tool to evaluate the masticatory efficiency. Comparison of the EMG recording was done for bio-engineered and conventional denture after 3 months of use. No statistical significant difference in peak to peak amplitude values for both the side and both muscles (masseter, temporalis) for both the dentures were found. This indicates that masticatory efficiency is comparable in both dentures. Hence, the bio-engineered teeth could be an alternative option to poor foundation cases.
Evaluation of the effect of the bio-engineered teeth on residual ridge resorption could not be included in the study. Furthermore, the effect of resilient lining of teeth and conventional teeth on RRR was compared by elCharkawi and elMahdy and found that using resilient layer significantly minimised ridge reduction. Long-term studies for the effect on residual ridge and patient satisfaction are required.
| Conclusion|| |
There is no difference in masticatory efficiency found between complete dentures with bio-engineered teeth and conventional denture teeth when assessed using EMG analysis.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3], [Figure 4], [Figure 5]