Analysis of Masticatory Cycle Efficiency in Complete Denture Wearers

Purpose: This study assessed masticatory efficiency and duration of the masticatory cycle in 14 asymptomatic patients with severe bone resorption. All patients had worn complete dentures for over 10 years. Recall visits were scheduled at 5 months and 1 year after receiving new dentures.
Materials and Methods: Fourteen patients were evaluated in this study. The Research Diagnostic Criteria questionnaire and tests of the efficiency and duration of the masticatory cycle were performed with artificial food before, 5 months after, and 1 year after new dentures were delivered. Masticatory efficiency was assessed using a sieve system; artificial food was ground for 35 masticatory cycles and monitored by the operator.
Results: Masticatory efficiency at 5 months was significantly improved for the 0.42-mm mesh. An improvement in masticatory efficiency and a reduction in mastication time were observed with the new dentures after 1 year.
Conclusion: The results of this study indicated that 5 months did not allow enough time to demonstrate improved muscular capacity and ability after receiving new dentures. After 1 year, the duration of the masticatory cycle was reduced, and masticatory efficiency was significantly improved.     

Effects of intense chewing on some parameters of masticatory function.

This study recorded the influence of 30 minutes of intense chewing on the masticatory function in 17 healthy subjects. Functional recordings of mandibular movements and velocity, measurements of masticatory efficiency, maximal occlusal force, and occlusal force endurance time were performed before and after functional stimulation and finally in a 2- to 5-day follow-up registration. After intense chewing, a substantially decreased masticatory cycle and occlusal level phase duration were recorded. No major mandibular displacements or changes in velocity were recorded. Masticatory efficiency and maximal occlusal force in the incisal region diminished after 30 minutes of intense chewing. Occlusal force endurance time was also lowered after intense chewing. The measurements were close to their original values at the follow-up. Intense chewing had various short-term effects on masticatory function, including a significant reduction of masticatory efficiency, maximal occlusal force, occlusal force endurance, and masticatory cycle duration.     

The role of oral sensorimotor function in masticatory ability

In order to investigate the relationship between oral sensorimotor ability and masticatory function, an oral stereognosis ability (OSA) test, masticatory performance and efficiency was employed for 15 dentate subjects. Subjects were instructed to orally identify OSA test pieces blindly. The response score and sum of the duration time for identification were used for analysis as OSA score and OSA response time. Masticatory function was evaluated using a sieving method with 3 g of peanuts. Masticatory performance was calculated with the weight percentage of portions finer than 1700 microm by the total volume after 20 chewing strokes. Masticatory efficiency was calculated by the declination rate of median particle size which is defined by the Rosin-Rammler equation. To analyse the relationship between OSA variables and masticatory ability, the correlation coefficient was calculated. The results summarized as a significant correlation was found only between OSA score and masticatory efficiency. However, a significant correlation could not be found between other OAS variables and masticatory ability. It was revealed that positive correlation existed between oral stereognosis ability and masticatory ability. It was suggested that the role of oral sensorimotor function might affect the masticatory function.     

牙源性角化囊肿手术对咀嚼效能的影响

目的：评价下颌骨牙源性角化囊肿手术及可摘部分义齿修复对患者咀嚼效能的影响。方法：通过临床检查和复习X线片明确术前囊肿累及的牙数和术后的缺失牙数,采用吸光度法测定咀嚼效率。对结果进行比较和统计学分析。结果：手术后的平均失牙数下颌骨部分切除术组明显多于囊肿剜除术组和袋形术组;可摘部分义齿修复前及修复后的吸光度值,颌骨切除术组均低于囊肿剜除术和袋形术组（P〈0．01）;囊肿剜除术和颌骨切除术组义齿修复后吸光度值明显提高（P〈0．01）。结论：下颌骨牙源性角化囊肿手术后患者咀嚼效能变化与手术方法或牙缺失数有关。术后可摘部分义齿修复可明显改善患者的咀嚼功能。     

The effect of new complete dentures on mastication and dietary intake

Masticatory efficiency, the subjective experience of masticatory performance, and dietary intake were measured for 43 subjects who were provided with new complete dentures. The subjects were tested on three occasions: with the old complete dentures, with the new complete dentures when free from symptoms, and with the new dentures about 4 months after insertion. Masticatory efficiency and the subjective experience of masticatory performance increased significantly when the subjects were provided with new dentures, but no changes were found in the dietary intake. With the new dentures the masticatory efficiency and the subjective experience of masticatory performance were correlated to each other.     

Masticatory function after activator treatment: An analysis of masticatory efficiency,occlusal contact conditions and EMG activity

Pancherz, H. Anehus, M. Masticatory function after activator treatment. An analysis of masticatory efficiency, occlusal contact conditions and EMG activity.

Masticatory function was investigated in nine patients with relapse and ten patients without relapse of overjet after activator treatment, Masticatory efficiency, evaluated by a chewing test, was related to the number of intermaxillary tooth contacts and the electromyographic (EMG) activity from the temporal and masseter muscles during chewing. The results of the investigation indicated that a reduced masticatory efficiency was connected with fewer intermaxillary tooth contacts and less EMG activity from the temporal and masseter muscles. In patients with relapse of overjet, masticatory efficiency and muscle activity was reduced in comparison with patients without relapse. The relationship between the number of tooth contacts and masticatory efficiency was poor in the relapse patients. Unstable occlusal conditions and atypical tongue function may be an explanation.     

Masticatory ability, denture quality, and oral conditions in edentulous subjects.

This study investigated the relationships between the ability of 38 patients with complete dentures to comminute a tough artificial test food and their answers to questions about the chewing experience. Also, clinical assessments were made of denture quality and oral conditions. Significant but weak relationships were found between the ability to comminute the test food and the subjective chewing experience as well as the degree of resorption of the mandibular residual ridge. Masticatory ability is conceivably determined by many other factors as well. Results indicate that dentists cannot rely on asking denture wearers about chewing problems and clinical responses with respect to oral conditions and denture quality for predicting those patients' masticatory abilities. The ability of wearers of complete dentures to comminute tough foods should be determined individually by a series of chewing tests.     

Masticatory function in subacute TMD patients before and after treatment

Summary  Masticatory function can be impaired in temporomandibular disorders (TMDs) patients. We investigated whether treatment of subacute non-specific TMD patients may influence oral function and clinical outcome measures. Fifteen patients with subacute TMD participated in the study. We quantified masticatory performance, maximum voluntary bite force, muscle activity and chewing cycle duration before and after treatment. Masticatory performance and bite force of patients were compared with the results obtained for an age- and gender-matched group of subjects without TMD complaints. Furthermore, we determined possible changes in anamnestic and clinical scores from questionnaires (mandibular function impairment questionnaire; MFIQ), pain scores and clinical outcome measures. Maximum bite force significantly increased, although the values after treatment were still significantly lower than those of the subjects without TMD complaints. The corresponding electromyography values did not show significant change after treatment. The masticatory performance of the patients remained unaltered; patients chewed significantly less efficient than controls. The average duration of chewing cycles significantly decreased after treatment. We observed a significant improvement in MFIQ scores. During the clenching and chewing tasks, the visual analogue scale scores were significantly higher than before these tasks. We may conclude that subacute temporomandibular joint disorders negatively influence chewing behaviour. Bite force, chewing cycle duration and also perceived mandibular function significantly improved after treatment, although the masticatory performance remained unaltered.     

Long-term effects on chewing with mandibular fixed prostheses on osseointegrated implants

Twenty-seven edentulous patients with denture adaptation problems were first given optimal conventional complete dentures and then a fixed prosthesis on osseointegrated dental implants in the lower jaw (and a complete maxillary denture). Masticatory function was evaluated by means of a questionnaire, a comminution test for chewing efficiency, and bite force measurements on four occasions: with the original (I) and optimal complete dentures (II) and 2 months (III) and 3 years (IV) after insertion of the fixed mandibular prosthesis on implants. No significant improvement of masticatory function was found after conventional denture treatment. After insertion of the fixed mandibular implant bridge, a marked improvement of the patients' assessment of their chewing ability and of the results of the chewing efficiency test and the bite force measurements was recorded. The test results were further improved after the 3-year observation period, which indicates that adaptation to the new prosthetic situation is a gradual process.     

The effect of removable partial dentures on mastication and dietary intake

Masticatory efficiency, the subjective experience of masticatory performance, and dietary intake were evaluated in 19 subjects who were treated with a removable partial denture in the lower jaw. The subjects were tested on three occasions: before treatment, with the dentures when free from symptoms, and about 4 months after the dentures were inserted. Masticatory efficiency and the subjective experience of masticatory performance increased significantly after the subjects were provided with the dentures, but no changes were found in the dietary intake.     

A comparative evaluation of masticatory efficiency of fixed and removable restorations replacing mandibular first molars

In replacing a missing mandibular first molar, removable and fixed partial dentures were constructed for each of ten subjects. Masticatory function tests with peanuts were made before, immediately after, and one week and one month subsequent to insertion of both types of prostheses.Masticatory performance, the number of strokes, and chewing time until swallowing were similar with the removable and fixed partial dentures. One month after insertion, a slight but statistically significant decrease in the total time of mastication was observed.The electromyogram of the anterior belly of the temporal muscles made during peanut chewing was also analyzed. It was found that, as a result, the rhythm of the masticatory movement after the cementation of fixed partial denture was more regular and that the duration of movement bursts became shorter than that with the removable partial denture.     

Masticatory function after activator treatment. An analysis of masticatory efficiency, occlusal contact conditions and EMG activity.

Masticatory function was investigated in nine patients with relapse and ten patients without relapse of overjet after activator treatment, Masticatory efficiency, evaluated by a chewing test, was related to the number of intermaxillary tooth contacts and the electromyographic (EMG) activity from the temporal and masseter muscles during chewing. The results of the investigation indicated that a reduced masticatory efficiency was connected with fewer intermaxillary tooth contacts and less EMG activity from the temporal and masseter muscles. In patients with relapse of overjet, masticatory efficiency and muscle activity was reduced in comparison with patients without relapse. The relationship between the number of tooth contacts and masticatory efficiency was poor in the relapse patients. Unstable occlusal conditions and atypical tongue function may be an explanation.     

A structural equation model relating objective and subjective masticatory function and oral health‐related quality of life in patients with removable partial dentures

Summary The aim of this study was to investigate the relationships between objective masticatory function with respect to masticatory performance and food mixing ability, patients’ perception of chewing ability and oral health‐related quality of life (OHRQoL). Partially dentate patients with removable partial dentures (n = 131, mean age 67·1 year) participated in the study. Four tests were performed to evaluate objective and subjective masticatory function and OHRQoL. Masticatory performance and food mixing ability were assessed using peanuts or a two‐coloured wax cube as test items. Patients’ perception of chewing ability was rated using a food intake questionnaire. OHRQoL was measured using the Japanese version of the oral health impact profile. A structural equation model was constructed based on hypothesis in which objective masticatory function would be related to OHRQoL via perceived chewing ability as a mediator. Structural equation modelling analysis found a statistically significant medium effect of perceived chewing ability on OHRQoL and statistically significant medium or small effects of masticatory performance on perceived chewing ability and OHRQoL (P < 0·05); however, the effect of food mixing ability on perceived chewing ability or OHRQoL was not statistically significant (P > 0·05). A fit index indicated that the model fitted well to the data (Goodness‐of‐fit index = 0·99). These results suggest that perceived chewing ability is a critical factor for OHRQoL and that masticatory performance rather than food mixing ability is important for perceived chewing ability and OHRQoL in patients with removable partial dentures.     

Analysis of kinesiograph recordings and masticatory efficiency after treatment of non-reducing disk displacement of the temporomandibular joint

The purpose of this study was to clarify the kinesiographs of chewing movement and masticatory efficiency before and after treatment in patients with non-reducing disk displacement of the temporomandibular joint (TMJ). Twenty patients who were diagnosed with unilateral non-reducing disk displacement of the TMJ were treated with pumping of the joint with injection of sodium hyaluronate. Chewing movement patterns in these patients were evaluated, using mandibular kinesiography (MKG) at their initial visit and at mean 19-month follow-up and the results were compared. Masticatory efficiency was also measured. As controls, 23 volunteers without TMJ dysfunction were employed. Far from the results of normal volunteers, chewing movement patterns of the patients on MKG did not show deviation to the chewing side in the TMJ-unaffected-side chewing in the horizontal plane. However, such patterns of the patients became similar to those of normal volunteers after treatment. Masticatory efficiency of the patients improved after treatment, though it was impaired at initial visit. The MKG and masticatory efficiency test appeared to be a useful method of comparing masticatory function before and after treatment in patients with non-reducing disk displacement of the TMJ.     

Masticatory function with implant-supported overdentures

The type of attachment that is used in implant-supported mandibular overdentures may influence the retention and stability of the prosthesis and, thus, masticatory function. In this within-subject cross-over clinical trial, we examined the hypothesis that greater retention and stability of the overdenture improve the masticatory function. Eighteen edentulous subjects received 2 oral implants, a new overdenture, and, successively, 3 different suprastructure modalities: magnet, ball, and bar-clip. Masticatory performance, masticatory efficiency, and swallowing threshold were measured. The masticatory function significantly improved after implant treatment with each of the 3 attachments. We observed small differences in masticatory function among the 3 attachment types: slightly better masticatory performance with ball and bar-clip than with magnet attachments. The number of chewing cycles until swallowing hardly decreased after implant treatment. We conclude that significantly better masticatory performance, combined with a slightly smaller number of chewing cycles after implant treatment, results in smaller food particles being swallowed.     

义齿基托材质与患者初戴满意度及咀嚼效率的关系

目的研究患者初戴满意度及咀嚼效率与义齿基托材质的关系。 方法选取符合纳入标准的多数牙缺失的患者,采用复制义齿技术制作不同基托材质的纯钛组、钴铬组和塑胶组义齿。分别对三组义齿进行咀嚼效率及初戴满意度进行评价。 结果纯钛组义齿、钴铬组义齿明显较塑胶组义齿初戴时咀嚼效率高（P < 0.05）,不能认为纯钛组较钴铬组义齿初戴时的咀嚼效率高（t= 0.137,P= 0.898）。纯钛组义齿初戴时患者总体满意度明显高于另外两组。 结论义齿基托材质对患者咀嚼效率、初戴满意度有一定的影响,义齿的咀嚼效率并不完全取决于基托材料,患者初戴满意度与咀嚼效率等实际修复效果并不完全一致。     

Is the side with the best masticatory performance selected for chewing?

ObjectiveThis study assessed the degree of relationship between masticatory laterality and lateral asymmetry of masticatory performance using silicon pieces enclosed in a latex bag.DesignForty-two young adults with natural dentition participated in this cross-sectional, observational study. They performed four different masticatory assays, each consisting of five trials of chewing three pieces of silicon for 20 cycles. In one assay, they were asked to masticate unbagged silicon free-style, whilst in the three other assays they were asked to masticate bagged silicon free-style, unilaterally on the right-hand side and unilaterally on the left-hand side. The preferred chewing side was determined by calculating the asymmetry index for both the free-style assays. Masticatory performance was determined by sieving the silicon particles and the cycle duration was also recorded. Data were analysed using independent samples or paired t-test and linear regression.ResultsMasticatory function using the bagged silicon was similar to that using the unbagged silicon. A significant and positive relationship was observed between the preferred chewing side expressed as the asymmetry index and the side with better masticatory performance. Alternate unilateral chewers demonstrated better masticatory performance than unilateral chewers. However, when free-style and unilateral chewing were compared for each subject, unilateral chewing was found to be as efficient as – or even more efficient than – free-style chewing.ConclusionsThere is a positive association between the preferred chewing side and the more efficient side. Alternate unilateral mastication per se does not promote better masticatory performance than consistently unilateral mastication.     

Masticatory performance and chewing experience with implant-retained mandibular overdentures

The relationship between masticatory performance and chewing experience has not yet been explored for patients with implant-retained overdentures. Although many relationships have been found between parameters of objective and subjective oral function, the structure of these relationships remain unclear. Therefore, we studied in a randomized clinical trial the relationship between the comminution of an artificial test food, i.e. masticatory performance, and the subjective chewing experience. The trial involved a comparison between two groups receiving implant treatment and one group receiving conventional complete dentures (CD). The implant treatment involved either a mainly implant-supported mandibular overdenture on a transmandibular implant (TMI) or an implant-tissue-supported mandibular overdenture on two IMZ implants (IMZ). Masticatory performance as well as chewing experience were substantially better for the implant-retained overdentures compared with the complete denture group. No significant differences emerged between the TMI and the IMZ group. A multiple regression analysis did not provide any comprehensibility in the relationship between masticatory performance and the variables of chewing experience. In the linear structural relation analysis (LISREL) no direct relationship was found between masticatory performance and functional complaints mandibular denture. The results show that an improvement in masticatory performance does not imply the same improvement in chewing experience and vice versa.     

Masticatory function in patients with extensive fixed cantilever prostheses

Eleven patients with complete maxillary dentures and 12-unit fixed partial dentures that included the mandibular canines were studied before and during specific intervals after prosthodontic treatment. Established methods for evaluation of oral function were used and the last examination was performed 30 months after treatment. All patients reported that their masticatory function had been substantially improved and there were no symptoms of dysfunction in the masticatory system. Masticatory efficiency improved after the prosthodontic treatment because both the number of cycles before the initial swallow and the total number of strokes including the time for completed mastication diminished after treatment. The occlusal force elevated after the prosthodontic treatment. Although great individual variations were recorded for all occasions and force levels, forces recorded on the extensions of the cantilever were similar to those on the canine regions.     

A comparative study of masticatory efficiency between partial denture wearers having one remaining tooth and complete denture wears]

Masticatory efficiency is one of the important indexes of judging masticatory function after dentures restored.The aim of this study was to measure and analyze masticatory efficiency of partial dentur wearers having one tooth left and complete denture wearers,by using a method of measuring msticatory crushed granules.The results showed that the crushed granules for partial denture wearers with one remaining tooth were smaller than that for complete ones.Therefore,partial dentures with a few remaining teeth were better than complete ones on effects.