Use of strain elastography in comparative evaluation of elasticity of masseter muscle in complete denture as against implant supported overdenture.

Introduction

Methods

24 completely edentulous patients would be selected for the study. Before beginning the procedure, all patients would have their questions about the study answered and would sign a consent form. Complete dentures would be constructed for 12 edentulous patients and implant supported denture would be fabricated for other 12 edentulous patients in the postgraduate clinic of Department of Prosthodontics and Crown & Bridge. These patients would be taken to Department of Radiology, AVBRH, for the sonographic scanning. The patient would be given the instruction to sit up straight, with their heads relaxed and unsupported. The transducer probe would be generously covered in water-based gel before being positioned with the best pressure 15 mm above the inferior border of the mandible and perpendicular to the anterior border of the muscle. After inserting the dentures, the initial scanning would take place while the wearer was at rest. The patient would be told to close his lips, with his jaw in a relaxed position and without making any contact with his teeth. A second scan would be conducted while your teeth are clenched the most. For which the patient would be told to clench their rear denture teeth in a centric relation for roughly five seconds on each side. A standard sonographic image is overlay with coloured images to display the strain ratio on the screen. With respect to subcutaneous fat, the masseter muscle ratio is calculated.

The patient would be sent home with the directive to wear the dentures every day for the next three months. After three months, the patient would be called back for follow-up, and another scan would be performed. The scanning would take place while the subject was at rest and maximum clenching tooth position. In the patient who has received rehabilitation with implant-supported dentures, the treatment would be repeated exactly as stated above.

Discussion

The study suggests that there would be increase in elasticity of masseter muscle in completely edentulous patient after rehabilitation. However, implant supported denture would show higher values than the conventional complete denture.

Many research has been conducted to examine the various traits of the masseter muscle as well as the alterations that take place with full tooth loss and temporomandibular disorders. For example, Parag Bhoyar et al. (2011)⁴ used ultrasonography to assess the impact of complete edentulism on the thickness of the masseter muscle and the alterations during rehabilitation with complete dentures. In complete denture wearers and dentulous people, masseter muscle scanning was done in both relaxed and constricted states. The study demonstrated an increase in muscle thickness following a 3-month follow-up from the time the denture was inserted, although it was still lower than that of patients who were dentulous and in the same age group.

Yoshiki Ariji et al. (2012)⁵ studied the link between the hardness measured by a hardness metre and the masseter muscle elasticity index (MEI) ratio acquired by sonographic elastography in healthy volunteers and found a substantial correlation between them. Also, he explained the characteristics of the masseter muscle hardness in TMD patients who also experience myofascial pain. As a result, it was determined that elastography might be utilised as an additional imaging tool to assess muscle hardness.

A study by Busato et al. (2015)⁶ examined the viability of using ultrasonic imaging to measure the pattern of muscle distortion in the masseter. Following the placement of a medical device that modifies the distance between the dental arches, ultrasound was performed while teeth clenched naturally and was repeated three times. The same strain patterns appeared again in many ultrasound scans of the same patient and changed as a result of the addition of a medical apparatus. This study proved that masseter strain measurement is a sensitive and reproducible instrument for the examination of the masticatory organ's functional analysis.

Meltem Mayil et al. (2018)⁷ evaluated the masseter muscle's ultrasonographic appearances in dentate and edentulous patients without TMDs. Bilaterally, the thickness was measured both at rest and at maximal contraction. The visibility and size of the interior echogenic bands were used to determine the masseter's appearance. The investigation made it clear that the masseter muscle's ultrasonographic characteristics varied between dentate and edentulous subjects.

A systematic review on the application of elastography to the evaluation of the masseter muscle in both healthy subjects and patients with masseter muscle diseases was published by Anna Olchowy et al. (2020).⁸ In his opinion, elastography is a useful tool for determining the elasticity of the masseter muscle.

Moustafa Abdou ELsyad et al. (2021)⁹ studied at the masseter muscle's EMG activity in 18 patients who were completely edentulous and had atrophied mandibular ridges. He provided conventional complete dentures to these patients, who served as the control group. Next, using the "All-on-four" approach, four implants were promptly loaded and implanted between the mental foramina on the same patients after three months. Following osseointegration, the patients were randomly assigned either fixed prostheses (FPD) or milled bar overdentures (MBO). Three months after utilising CD, FPD, and MBO, the primary (amplitude) and secondary (chewing rate, time of the masticatory cycle, time of masticatory burst, and masticatory time) outcomes were assessed. MBO is not less effective than fixed prosthesis, he determined, and both considerably increased muscular activity, chewing rate, and time of chewing.