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

Plaque-induced gingivitis: Case definition and diagnostic considerations

OBJECTIVE

Clinical gingival inflammation is a well-defined site-specific condition for which several measurement systems have been proposed and validated, and epidemiological studies consistently indicate its high prevalence globally. However, it is clear that defining and grading a gingival inflammatory condition at a site level (i.e. a "gingivitis site") is completely different from defining and grading a "gingivitis case" (GC) (i.e. a patient affected by gingivitis), and that a "gingivitis site" does not necessarily mean a "GC". The purpose of the present review is to summarize the evidence on clinical, biochemical, microbiologic, genetic markers as well as symptoms associated with plaque-induced gingivitis and to propose a set of criteria to define GC.

IMPORTANCE

A universally accepted case definition for gingivitis would provide the necessary information to enable oral health professionals to assess the effectiveness of their prevention strategies and treatment regimens; help set priorities for therapeutic actions/programs by health care providers; and undertake surveillance.

FINDINGS

Based on available methods to assess gingival inflammation, GC could be simply, objectively and accurately identified and graded using bleeding on probing score (BOP%) CONCLUSIONS: A patient with intact periodontium would be diagnosed as a GC according to a BOP score ≥ 10%, further classified as localized (BOP score ≥ 10% and ≤30%) or generalized (BOP score > 30%). The proposed classification may also apply to patients with a reduced periodontium, where a GC would characterize a patient with attachment loss and BOP score ≥ 10%, but without BOP in any site probing ≥4 mm in depth.

Characterization of maxillary central incisor: novel crown-root relationships

OBJECTIVES

The periodontal biotype includes crown features of the maxillary central incisor (MCI), whereas root measures have been less studied. The aim of our study was to morphologically characterize MCI and search relationships between crown and root measures.

MATERIAL AND METHODS

One hundred-fifty MCIs were used. On each tooth, several crown and root reference points were marked and the following measures were done: On crown: mesio-distal (MD = major, md = minor), axial (crown length, cervical convexity) and buccolingual diameters (Cbl); On root: mesio-distal (Rmd) and buccolingual diameters (Rbl); and tooth length. A ratio between md and MD was made in order to assess dental forms. Root diameter prediction was assessed by means of multiple and single linear regression analyses, with variable selection by backward method. Reliability of measurements was estimated by the Pearson correlation coefficient.

RESULTS

Dental form groups were: Stout type 56.67 %, Intermediate type 22.67 %, and Strangled type 20.67 %. A significative association was found between Rbl and Cbl (p = 0,000), Rmd with md (p = 0.000), and Rmd with MD (p = 0.000). The results allow predicting root diameters through crown measures.

CONCLUSIONS

There is a direct relationship between crown and root features, which allows the prediction of root diameters with a high accuracy (95 %), regardless of tooth form.

CLINICAL RELEVANCE

The morphometric data assess tooth diameters more accurately and could improve treatment planning, offering a more comprehensive approach to the periodontal biotype concept.

Interleukin-1 beta levels in gingival crevicular fluid and serum under naturally occurring and experimentally induced gingivitis

AIMS

To evaluate the interleukin-1 beta (IL-1 beta) levels in gingival crevicular fluid (GCF) and serum in either naturally occurring (N-O) or experimentally induced (E-I) plaque-associated gingivitis.

MATERIAL AND METHODS

Thirty-seven periodontally healthy subjects were evaluated in real life conditions (N-O gingivitis) as well as after 21 days of experimental gingivitis trial (E-I gingivitis). During the experimental gingivitis trial, in one maxillary quadrant (test quadrant), gingival inflammation was induced by oral hygiene abstention, while in the contralateral (control) quadrant, oral hygiene was routinely continued. IL-1 beta concentrations in N-O and E-I gingivitis were investigated for IL-1B(+3954) and IL-1B(-511) gene polymorphisms.

RESULTS

(i) GCF IL-1 beta concentrations in E-I gingivitis were significantly higher compared with N-O gingivitis; (ii) an intra-individual correlation between GCF concentrations of IL-1 beta detected in N-O and E-I gingivitis was observed in control quadrants, but not in test quadrants; (iii) IL-1 beta concentration in GCF was associated with IL-1B(+3954) genotype only at test quadrants; (iv) IL-1 beta was detectable in serum only at low levels in a limited number of subjects, without difference between gingivitis conditions.

CONCLUSIONS

Aspects of the bacterial challenge to the gingival tissues, such as the amount of plaque deposits and plaque accumulation rate, appear to affect the IL-1 beta levels in GCF in subjects with a specific IL-1B genotype.

Time as a factor in the identification of subjects with different susceptibility to plaque-induced gingivitis

OBJECTIVES

The purpose of this study was to assess whether identification of subjects with different susceptibility to plaque-induced gingival inflammation is dependent on the length of time of de novo plaque accumulation.

METHODS

Retrospective analysis of data obtained from a recently reported randomized split-mouth localized experimental gingivitis trial involving 96 healthy non-smokers. Gingival and plaque index, gingival crevicular fluid volume (GCF), angulated bleeding score, and the derived parameter cumulative plaque exposure (CPE) were recorded at days 0, 7, 14, and 21. The primary outcome variable to express severity of inflammation was GCF and each subject was a statistical unit. Based on subject distribution of GCF-day 21 residuals after standardization for CPE-day 21, two sub-populations (upper and lower distribution quartiles) were selected. They were, respectively, defined as "high responders" (HR) (n=24) and "low responders" (LR) (n=24) and characterized by significantly different severity of gingivitis to similar amounts of plaque deposits. The same analysis was repeated at days 7 and 14. Prevalence of HR and LR was compared between days using the chi(2) [ML] test.

RESULTS

For both day 7 and day 14, the quartile distribution of LR and HR was statistically significant (p=0.02). Fifty percent of LR and 71% of HR presented a consistent level of susceptibility to plaque-induced gingival inflammation even after only 7 and/or 14 days of plaque accumulation.

CONCLUSIONS

These findings support the concept that the subject-based susceptibility to plaque-induced gingival inflammation is an individual trait, only partly related to the length of time of exposure to plaque.

Variance components of gingival thickness

OBJECTIVES

Distinct periodontal phenotypes have been identified by cluster analysis, which is an explorative method with very low external validity. The aim of the present study was to investigate variance components of facial gingival thickness in young adults with mild gingivitis.

MATERIAL AND METHODS

Thirty-three non-smoking females, 18-23 years of age, with mild or moderate plaque-induced gingivitis participated. Gingival thickness was measured at every tooth present by use of ultrasound technology to the next 0.1 mm with a lowest measurement of 0.5 mm. Periodontal probing depth and clinical attachment level were measured with a pressure-controlled probe. Gingival bleeding index was assessed after probing on a 0-2 scale, where 1 was slight, and 2 was profuse bleeding on probing. The Silness-Loe plaque index was recorded. Multilevel variance components and random intercept models were built.

RESULTS

A 2-level (subject, tooth) variance component model of gingival thickness without any explanatory variable revealed an intercept (mean) of 0.93 +/- 0.02 mm. Subject variation of gingival thickness amounted to 4.2% of the total variance. Addition of tooth- and subject-related covariates to the model revealed, after adjusting for tooth type, an association with periodontal probing depth (estimated coefficient 0.067 +/- 0.025), and considerable association with average bleeding index (-0.395 +/- 0.149) and plaque index (0.125 +/- 0.048). Variation at the tooth level was drastically reduced; subject variation amounted to 5.2%.

CONCLUSION

Gingival thickness is mainly associated with tooth-related variables. Bleeding tendency is higher if gingiva is thin. Subject variability related to periodontal phenotype may add to the total variance, however, to a very low extent.