ABSTRACT
OBJECTIVES: For evidence-based evaluation of guided bone regeneration (GBR), accurate registration of changes in gingiva and bone levels is needed. A new method is introduced and evaluated. METHODS: In a clinical trial with 30 patients, alginate impressions of the surgical area including the interproximal gingiva and alveolar bone at the adjacent teeth were made in duplicate prior to and during GBR surgery, fixture installation and abutment connection. Poured in hard stone, the casts were used for repeated measurements of the level of the free gingival margin and the alveolar bone with an automated probe (Florida disc-probe(R)), using the incisal edge as a fixed reference point. The reproducibility and accuracy of these measurements were evaluated by means of the Intraclass Correlation Coefficients and Generalizability Theory. The effect of treatment was evaluated by multivariate analysis of variance. RESULTS: Generalizability Theory indicated a high accuracy of the gingiva- and bone-level measurements: the Intraclass Correlation Coefficients for gingiva and bone levels were 0.99 and 0.98, respectively. The intra-cast reproducibility was 0.09+/-0.07 mm (mean+/-SD) and the inter-cast reproducibility was 0.10+/-0.09 and 0.20+/-0.07 mm for gingiva and bone levels, respectively. Clinical applicability is demonstrated by the fact that manova revealed on average a small but highly significant (p=0.001) effect of the staged surgical intervention on the gingiva and bone levels at the adjacent teeth. CONCLUSION: It is concluded that the presented method makes it possible to evaluate reproducibly and accurately changes in gingiva and bone levels for GBR studies.
