Modulation of Clinical Expression of Plaque-induced Gingivitis: Effect of Incisor Crown Form

Modulation of Clinical Expression of Plaque-induced Gingivitis: Effect of Incisor Crown Form
2004

Journal of Dental Research

Š 2004 International and American Associations for Dental Research

L. Trombelli1,*, R. Farina1, R. Manfrini1, and D.N. Tatakis1,2

1 Research Center for the Study of Periodontal Diseases, University of Ferrara, Corso Giovecca 203, 44100 Ferrara, Italy; and
2 Section of Periodontology, College of Dentistry, The Ohio State University, Columbus, OH, USA;

* corresponding author, l.trombelli@unife.it

ABSTRACT

Evidence indicates that incisor crown form correlates with clinical periodontal features. It was hypothesized that incisor crown form may explain subject differences in gingivitis expression. The present experimental gingivitis study aimed to assess the effect of incisor crown form on plaque accumulation and gingival inflammation, and on individual susceptibility to plaque-induced gingivitis. Eighty-five periodontally healthy subjects were evaluated. A negative correlation was found between incisor crown width/crown length ratio and bleeding score (p = 0.045). From the 85 subjects, two groups of subjects with either Îlong-narrowĚ or Îshort-wideĚ incisor form were identified. The Îlong-narrowĚ group had a significantly higher bleeding score than the Îshort-wideĚ group (p = 0.014). No significant differences were found in the incisor crown width/crown length ratio between previously identified Îhigh responderĚ and Îlow responderĚ subjects (Trombelli et al., 2004a). In conclusion, incisor crown form appears to affect the bleeding response of inflamed gingival tissues, while it exerts no influence on explaining differences in individualsĚ susceptibility to plaque-induced gingivitis.

KEY WORDS: periodontal disease/gingivitis Ô dental plaque/diagnosis Ô gingivitis/diagnosis Ô tooth crown/anatomy

INTRODUCTION

The clinical anatomical characteristics of the periodontium may vary greatly among individuals. Two markedly different anatomical types of periodontium have been recognized: the Îflat-thickĚ type, characterized by slightly scalloped and bulky marginal gingiva, associated with short and wide incisor crown form; and the Îscalloped-thinĚ type, characterized by highly scalloped and thin gingiva and associated with long and narrow incisor crown form (Olsson and Lindhe, 1991; Olsson et al., 1993; M?ller and Eger, 1997; M?ller et al., 2000). Studies have shown that certain clinical manifestations of plaque-induced periodontal lesions may vary among subjects with different anatomical types of periodontium. Specifically, subjects with a Îscalloped-thinĚ periodontium, i.e., long and narrow incisor crown form, exhibit greater gingival recession (Olsson and Lindhe, 1991) and shallower probing depth (M?ller et al., 2000) than subjects with a Îflat-thickĚ biotype. The only reported study to examine the possible association of bleeding on probing with gingival anatomical characteristics in chronic gingivitis subjects found that, after adjustment for smoking status and tooth type, gingival dimensions (either thickness or width) did not influence bleeding tendency (M?ller and Heinecke, 2002). There appear to be no studies in the literature addressing the possible association between anatomical characteristics, and specifically tooth crown form, and clinical parameters in experimental gingivitis. It was hypothesized that incisor crown form is a host-dependent factor that modulates the clinical expression of plaque-induced gingivitis.

Severity of gingival inflammation is primarily dependent on quantitative (Lŕe et al., 1965; Breuer and Cosgrove, 1989) and interrelated qualitative (Theilade et al., 1966; Moore et al., 1982) characteristics of the accumulated bacterial plaque. However, several host-related factors, e.g., hormonal status and smoking, could modify the clinical expression of plaque-induced gingivitis (Mariotti, 1999; Tatakis and Trombelli, 2004). Severity of gingivitis in response to plaque accumulation may also be an individual trait (Wiedemann et al., 1979; Abbas et al., 1986), possibly dependent on genetically determined factors (Tatakis and Trombelli, 2004). As a first step toward characterizing such factors, we identified, from among a large pool of volunteers participating in a 21-day experimental gingivitis trial, two groups of individuals with significantly different levels of severity of gingival inflammatory response to plaque accumulation, expressed as gingival crevicular fluid levels, without any difference in either amount of plaque deposits or plaque accumulation rate (Trombelli et al., 2004a). These were described as Îhigh respondersĚ (HR) and Îlow respondersĚ (LR).

The aim of the present randomized, split-mouth, localized experimental gingivitis trial was to assess the impact of incisor crown form on gingivitis expression. Specifically, the study examined the effect of incisor crown form on clinical parameters of plaque accumulation and gingival inflammation. The possible association of incisor crown form with individual susceptibility to plaque-induced gingivitis, i.e., HR and LR, was also investigated.

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