Prosthodontic Research & Practice 

About: Prosthodontic Research & Practice is an academic journal. The journal publishes majorly in the area(s): Dentures & Masticatory force. It has an ISSN identifier of 1347-7021. Over the lifetime, 206 publications have been published receiving 748 citations.

Reproducibility and Accuracy in Measuring Masticatory Performance Using Test Gummy Jelly

Abstract: Purpose: To establish a simpler and more accurate method of measuring masticatory ability in routine dental practice compared to current methods.Materials and Methods: To find the most suitable conditions for assessing masticatory performance using the test gummy jelly, variable factors were investigated, such as temperature and length of rinse time in water, temperature of distilled water, and dissolution time of glucose. The accuracy of this test was confirmed by correlating the surface area of the jelly and the glucose concentration. A student's t-test or ANOVA was used for statistical analysis at the 5% level of significance. The Bonferroni method was used for multiple comparisons.Results: The glucose concentration decreased gradually (p<0.05) as the rinsing time increased but tended to remain unchanged at 30seconds or more. As the temperature of the distilled water for dissolving the glucose or the dissolution time increased, the glucose concentration constantly increased (p<0.05). A linear regression analysis showed that the concentration of glucose had a significantly high correlation to the surface area (mm2) of the comminuted jelly (r=0.993, p<0.01).Conclusion: The concentration of glucose dissolved from the comminuted particles of the test gummy jelly indicated high reproducibility and accuracy when the rinsing time, temperature of the distilled water, and dissolution time of the glucose were strictly prescribed.

The Effectiveness of Measuring Glucose Extraction for Estimating Masticatory Performance

Abstract: Purpose: The purpose of this experiment was to investigate the effectiveness of examining masticatory performance by measuring glucose extraction from chewing gummy jelly.Methods: Twenty healthy subjects were asked to chew 2g of gummy jelly and 3g of peanuts for 10, 20, and 30 strokes respectively. The masticatory value as measured by the sieve method was then compared with the amount of glucose extraction from chewing gummy jelly.Results: The relationship between the amount of glucose extraction and the masticatory value was positive (r=0.475-0.850). Both the amount of glucose extraction and the masticatory value were lowest for the 10 chewing strokes and significantly increased for the 20 and 30 chewing strokes (glucose extraction F=1179.6, P<0.01; masticatory value F=605.0, P<0.01). The standardized glucose extraction for the 10, 20, and 30 chewing strokes was 0.17, 0.34, and 0.49 respectively, and increased proportionally. The standardized masticatory values for the 10, 20, and 30 chewing strokes were 0.28, 0.35, and 0.37 respectively, and increased logarithmically.Conclusion: From these results it was concluded that the masticatory performance as measured by the amount of glucose extraction from chewing gummy jelly is an effective indicator of masticatory function and has a high potential for clinical application.

Development of New Food Intake Questionnaire Method for Evaluating the Ability of Mastication in Complete Denture Wearers

Abstract: Purpose: The purpose of this study was to reduce the number of food items for ease of use, and to eliminate the influence of food preferences (likes and/or dislikes) on an earlier version of the food intake questionnaire method for evaluating the ability of mastication in complete denture wearers which had been previously developed by the authors.Methods: The subjects were 262 complete denture wearers (average age: 76.7±6.1 years old, male: 128 persons, female: 134 persons). The food intake questionnaire composed of a list of 35 food items which were used in the study. All subjects were asked to assign a mark to each type of food according to one of five categories (easily eaten, eaten with difficulty, cannot be eaten, do not eat because of dislike, have not eaten since starting to wear dentures). In order to reduce the number of the initial 35 food items in the questionnaire, the correlation coefficient of the masticatory score, representing the masticatory ability before and after elimination of foods, was examined in all the subjects. The masticatory performance (MP) was also evaluated by a sieving method in all subjects.Results: In the questionnaire with 5 categories composed of 25 foods, the reliability coefficient (Cronbach’s α) was 0.939. There was significant correlation between the masticatory score using the 35 food item list and the new masticatory score using the new 25 food item list (r=0.95, P<0.01). There was significant correlation between the MP using the sieving method and the N-MS using the 25 food item list (r=0.62, P<0.01).Conclusion: It was confirmed that the new food intake questionnaire method, with a revised 25 food item list, was both valid and reliable.

Oral Dryness Examinations : Use of an Oral Moisture Checking Device and a Modified Cotton Method

Abstract: Purpose: This study compared oral dryness measured using an oral moisture checking device and the modified cotton method. Methods: Oral moisture was measured at the lingual mucosa (LM) and the buccal mucosa (BM) using an oral moisture checking device in 13 healthy adults (HA) and 13 patients with oral dryness (OD). The modified cotton method was performed in the same subjects by placing cottons under and over the tongue for 30 seconds and measuring the weight of the saliva absorbed by the cotton. Differences between groups were examined using the Mann-Whitney U-test. Results: The moisture percentage at the LM in the HA and OD groups was 30.0 ± 0.5 % and 28.6 ± 1.1 %, respectively, while the percentage at the BM was 30.3 ± 0.2 % and 29.6 ± 0.7 %, respectively. The amount of hypoglossal salivary secretion in the HA and OD groups was 0.339 ± 0.172 g and 0.036 ± 0.033 g, respectively, while the amount of salivary secretion on the tongue’ s surface was 0.059 ± 0.023 g and 0.011 ± 0.007 g, respectively. Both oral moisture and the amount of saliva at rest were significantly different between the HA and OD groups (P<0.05). Conclusion: Both the oral moisture checking device and the modified cotton method were useful for measuring oral dryness. An oral moisture level of 30 % or less, less than 0.1 g of saliva collected at the hypoglossus within 30 seconds, or less than 0.02 g of saliva collected from the surface of the tongue within 30 seconds may indicate oral dryness.

Influence of Changes in Occlusal Vertical Dimension on Tongue Pressure to Palate during Swallowing

Abstract: Purpose : The purpose of the present study was to examine the relationship of tongue pressure and changes in occlusal vertical dimension to swallowing.Materials and Methods : The volunteer subjects were four young male dentulous adults and eight elderly complete denture wearers. The tongue pressure to the palate was simultaneously recorded with electromyography (EMG) measurements of the suprahyoid muscles as the occlusal vertical dimension changed. The subjects were instructed to perform two actions : swallowing without any liquid or food (dry swallowing) and swallowing of 2 ml water (wet swallowing).Results : During dry swallowing, the maximum pressure decreased significantly as the vertical dimension increased in the young subjects. In the elderly, the maximum tongue pressure decreased monotonically as the vertical occlusion increased. The same results were clearly found for wet swallowing. Overall data suggested that the tongue pressure of the elderly group was lower and the duration of tongue pressure in wet swallowing was longer than that of the younger group.Conclusion : An increase of the vertical dimension decreased the tongue pressure to the palate, whereas a decrease of the vertical dimension affected the tongue pressure less. Tongue pressure is an important factor for the evaluation of tongue function, especially swallowing.