Fure S, Lingström P, Birkhed D
Department of Cariology, Institute of Odontology, Göteborg, Sweden.
J Dent Res. 1998 Aug;77(8):1630-7. doi: 10.1177/00220345980770081101.
Studies on the relationship between gum-chewing and calculus formation have produced contradictory results, and it is not clear whether frequent use of chewing gum promotes or inhibits calculus formation. Also, little is known about whether the addition of a small amount of urea to the chewing gum influences calculus formation. The aim of this investigation was to study the effect of sugar-free chewing gum--with and without urea--on calculus formation and some associated clinical variables. Three three-month periods were studied in a double-blind, crossover design, during which the subjects: (1) chewed 5 pieces/day of a sugar-free, urea-containing chewing gum (20 mg urea/piece); (2) chewed 5 pieces/day of a sugar-free, non-urea-containing gum; or (3) performed no gum-chewing. Twenty-nine persons, all calculus-formers, participated. They were scored for calculus at mesio-lingual, lingual, and disto-lingual sites on the 6 anterior mandibular teeth according to the Volpe-Manhold index. Plaque and gingival bleeding index, stimulated salivary secretion rate and buffer capacity, resting plaque pH, mutans streptococci in saliva and plaque, and lactobacilli in saliva were also determined. No differences in calculus formation were found among the 3 periods. The resting plaque pH was higher after the period with urea-containing gum than after the period with non-urea-containing gum and the no-gum period (p < 0.05). A slight increase in stimulated salivary secretion rate was found after the 2 gum periods (p < 0.05). The plaque and gingival bleeding indices decreased, while resting plaque pH and salivary buffer capacity increased throughout the entire study (p < 0.05). No significant differences in prevalence of the acidogenic micro-organisms were found among the test periods. The main conclusion from this study is that three months' frequent use of sugar-free chewing gum--with or without urea--neither promotes nor inhibits calculus formation.
关于咀嚼口香糖与牙石形成之间关系的研究产生了相互矛盾的结果，目前尚不清楚频繁使用口香糖是促进还是抑制牙石形成。此外，对于在口香糖中添加少量尿素是否会影响牙石形成，人们了解甚少。本研究的目的是探讨无糖口香糖（含尿素和不含尿素）对牙石形成及一些相关临床变量的影响。研究采用双盲交叉设计，分三个为期三个月的阶段进行，在此期间，受试者：（1）每天咀嚼5片无糖含尿素口香糖（每片含20毫克尿素）；（2）每天咀嚼5片无糖不含尿素口香糖；或（3）不咀嚼口香糖。29名均有牙石形成的受试者参与了研究。根据Volpe-Manhold指数，对下颌6颗前牙的近中舌侧、舌侧和远中舌侧部位的牙石进行评分。还测定了菌斑和牙龈出血指数、刺激唾液分泌率和缓冲能力、静息菌斑pH值、唾液和菌斑中的变形链球菌以及唾液中的乳酸杆菌。三个阶段之间在牙石形成方面未发现差异。含尿素口香糖阶段后的静息菌斑pH值高于不含尿素口香糖阶段和不咀嚼口香糖阶段（p<0.05）。两个口香糖阶段后刺激唾液分泌率略有增加（p<0.05）。在整个研究过程中，菌斑和牙龈出血指数下降，而静息菌斑pH值和唾液缓冲能力增加（p<0.05）。在各测试阶段之间，产酸微生物的患病率未发现显著差异。本研究的主要结论是，三个月频繁使用无糖口香糖（含或不含尿素）既不促进也不抑制牙石形成。
