Influence of the height of the mandibular ridge on the masticatory function during the functional adaptation with new complete dentures

Abstract

Influence of the height of the mandibular ridge on the masticatory function during the functional adaptation with new complete dentures The period of functional adaptation to a new conventional complete denture embraces many transitory issues, and this period is directly related to the rehabilitation success. Objective: This clinical trial evaluated the influence of the height of mandibular ridge on the masticatory function of complete denture (CD) wearers during the adaptation period. Methodology: A total of 28 individuals wearing new CDs (NR, n=14, normal mandibular ridges, 64±12.5 years, 9 female; RR, n=14, resorbed mandibular ridges, 69±6.8 years, 9 female) were assessed at 24 hours, 30 days, three months and six months after the insertion of the CDs for masticatory performance (MP, sieves method), satisfaction with CDs (questionnaire) and maximum occlusal bite force (MOBF) (gnatodynamometer). The classification of the mandibular ridges followed the Kapur index. Data of MP and MOBF were analyzed by twoway ANOVA and satisfaction with CDs was analyzed by Generalized Estimating Equations (GEE), α=.05. Results: Participants with NR presented better masticatory performance (p=.000-NR 30.25±9.93%, RR 12.41±7.17%), general satisfaction (p=.047), retention of mandibular denture (p=.001), chewing ability (p=.037), and comfort of wearing a mandibular denture (p=.000). Regardless of the mandibular ridge, MP (p=.000) was higher at three (21.26±12.07%) and six months (24.25±12.26%) in comparison to 24 hours (18.09±10.89%), the MOBF (p=.000) was higher at three months (78.50±6.49 N) compared to 24 hours (57.34±5.55 N) and 30 days (62.72±5.97 N), and the comfort of wearing a mandibular denture (p=.002) at three months (1.61 ± 0.07) was greater than 24 hours (1.29±0.10) and 30 days (1.36±10). Conclusions: The study suggests that the participants with NR have higher MP and satisfaction with their CD, regardless of the follow-up period after the insertion of the new CD. After subjects received the CD, a period of 3 months was necessary for achieving better achievement MOBF, MP, and self-perceived comfort with the mandibular denture, regardless of the height of the mandibular ridge.

The impact of residual ridge morphology on the masticatory performance of complete denture wearers

“…This was supported by the results of the covariance analysis, indicating that the mandibular RR height had the strongest effect on the MP of wearers, followed by the combined RR forms and total occlusal contact area. This result was consistent with another study which found that patients with a normal mandibular RR height had a better MP than those with an RR resorption [ 15 ]. Their findings suggested that the mandibular RR height was strongly related to mandibular CD retention and stability, causing discomfort during the function and eventually affecting the MP [ 15 ].…”

“…Previous studies have also shown that RR morphology and resiliency influenced the retention and stability of conventional CDs [ 21 , 31 , 53 ]. Retention and stability are said to be determining factors for chewing ability [ 15 ].…”

“…In addition, in cases of upper and lower CD, the combination of RR morphology is expected to affect denture stability and, consequently, MP, but we have not found any studies reporting on this. The relationship between RR morphology and MP in CD patients has been shown in several papers [ 9 , 15 , 18 , 31 , 32 ]. On the other hand, in these reports, no studies examined contributory factors other than RR morphology that affect MP.…”

“…In Japan, the proportion of removable denture (hereinafter abbreviated as “denture”) wearers increases significantly with age, with about half of those ≥85 years old wearing complete dentures (CDs) [ 8 ]. Studies have reported that CD wearers have more difficulty chewing hard foods than those with natural dentition [ 9 , 10 ], with their masticatory performance (MP) being around 50% of those with natural dentition [ [10] , [11] , [12] , [13] , [14] , [15] ]. CD wearers chew longer, increasing the number of chewing cycles at a decreased masticatory rate and swallowing coarser food particles [ 16 ], eventually influencing their general health, increasing the risk of physical frailty, cognitive decline, and reduced quality of life [ 10 ].…”

“…The MP of denture wearers is influenced by many factors, such as tooth loss [ 13 , 17 , 18 ], residual ridge [ 1 , 9 , 13 , [18] , [19] , [20] , [21] ], maximum bite force [ [15] , [17] , [22] , [23] ], the tongue [ [22] , [24] ], and lip function [ 2 ], salivary secretion [ 15 , 25 , 26 ], previous experience with dentures [ 15 ], and denture stability, and retention [ 9 , 15 , 21 , 27 , 28 ]. Among those factors, poor residual ridge (RR) morphology has always been a primary concern for clinicians hoping to achieve successful treatment because RR height and form are essential to support the denture and prevent dislodgment [ 21 ].…”