Department of Prosthodontics and Periodontology, State University of Campinas, Sao Paulo, Brazil.
Int J Prosthodont. 2012 Sep-Oct;25(5):472-9.
The aim of this study was to determine the influence of occlusal support length (OSL) of free-end removable partial dentures (RPDs) on masticatory function.
Twenty-three subjects (mean age: 55.2 ± 8.4 years) who were edentulous in the maxilla and classified as Kennedy Class I in the mandible were selected. Subjects received new maxillary complete dentures and mandibular RPDs. Five OSL conditions were determined by RPD artificial tooth wear: full occlusal support (L1, control), OSL to first molar (L2), OSL to second premolar (L3), OSL to first premolar (L4), and absence of occlusal support (L5). Masticatory performance and efficiency were evaluated using the sieve method. Chewing rate was defined as the number of masticatory cycles per minute. Bolus selection opportunities and bolus breakage function were evaluated using the one-chew method. Qualitative and quantitative measurements of masticatory cycle patterns were recorded kinesiographically. Data were analyzed using repeated-measures analysis of variance and Friedman and Fisher exact tests (α = .05).
Masticatory performance and efficiency decreased (P < .05) from L1 (5.46 ± 0.64 mm and 51.21% ± 19.44%, respectively) to L5 (6.24 ± 0.44 mm and 24.50% ± 15.98%, respectively). Chewing rate was higher for L4 than L1 (P < .05). Bolus selection chances and bolus breakage function decreased as OSL was reduced (P < .05); however, there were no differences in masticatory cycle pattern among the OSL conditions (P > .05).
Reduction of OSL altered masticatory function, thereby decreasing masticatory performance and efficiency resulting from a lower capacity to select and break down food.
本研究旨在探讨游离端可摘局部义齿（RPD）的牙合支托长度（OSL）对咀嚼功能的影响。
选择 23 名上颌无牙颌且下颌为 Kennedy 第一类的患者（平均年龄：55.2 ± 8.4 岁）。患者接受上颌全口义齿和下颌 RPD 修复。通过 RPD 人工牙磨损确定 5 种 OSL 条件：全牙合支托（L1，对照组）、支持至第一磨牙（L2）、支持至第二前磨牙（L3）、支持至第一前磨牙（L4）和无牙合支托（L5）。使用筛法评估咀嚼性能和效率。咀嚼率定义为每分钟咀嚼循环次数。使用一口咀嚼法评估食团选择机会和食团破碎功能。使用运动学记录咀嚼循环模式的定性和定量测量。使用重复测量方差分析和 Friedman 和 Fisher 精确检验（α =.05）对数据进行分析。
咀嚼性能和效率从 L1（5.46 ± 0.64mm 和 51.21% ± 19.44%）下降至 L5（6.24 ± 0.44mm 和 24.50% ± 15.98%）（P <.05）。L4 的咀嚼率高于 L1（P <.05）。随着 OSL 的减少，食团选择机会和食团破碎功能下降（P <.05）；然而，在 OSL 条件下，咀嚼循环模式没有差异（P >.05）。
OSL 的减少改变了咀嚼功能，从而降低了咀嚼性能和效率，因为选择和分解食物的能力降低。
