15 November 2021

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Clinical and histological reaction of periodontal tissues to deep marginal elevation

Edoardo Mancuso

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Direct composite restoration requires strict adhesive protocols to be followed to achieve optimal results in terms of clinical success. However, the application of adhesive material is especially challenging when it occurs in the subgingival area. This is a critical area for placement of the cervical margin of restorations also because of the potentially negative impact on biofilm accumulation, the possible direct irritation of the gingival tissues, and the possible invasion of the biological width. 

Nevertheless, when there is a need for endodontic therapy in teeth with massive subgingival crown destruction, to allow for stable isolation of the unit with a rubber dam, the subgingival application of composite might be the most suitable technique. Dental restorative materials have been extensively studied, particularly concerning adhesion, usage, finishing, and esthetics. An area of particular interest is the biocompatibility of composites, especially in conditions in which these materials are placed at the gingival margin or within the gingival sulcus.

In this regard, a clinical and histological study, carried out by Professor Generali and his team and published in the Journal of Clinical and Oral Investigation, focused on the response of supracrestal periodontal tissues to subgingival composite restorations. 

Materials and methods

In the study, patients in good general health and without relevant oral or periodontal diseases were screened for the presence of at least one tooth presenting with deep intrasulcular caries requiring endodontic treatment; post-and-core direct reconstruction with composite; and, after the follow-up period of observation, indirect reconstruction with a single prosthetic crown. For each studied restoration, the cervical margin of the reconstruction was allocated within the gingival sulcus 3 mm apart from the bone, thereby  al care program with weekly recalls for 3 months, with the aim to limit as much as possible plaque accumulation and the possible subsequent, plaque-associated gingival inflammation.

Probing depth (PD), Full mouth plaque score (FMPS), and Full mouth bleeding score (FMBS) were evaluated at baseline and after 3 months.

After the crown lengthening, an all-around secondary, extended to the attached and interproximal gingiva was harvested for the histologic examination of both control and test sites (groups A and B). 

The gingival samples were examined and the amount of inflammation in the connective tissue was evaluated in the area of gingival tissues adjacent to the composite (group B) and the area adjacent to the natural surface of the tooth (group A). 

Results

For the research, a total of 48 patients were screened for the presence of at least one instance of subgingival caries. Of them, twenty-nine subjects, 12 men and 17 women fulfilled the stepwise entry criteria of the study. 

At baseline, FMPS and FMBS were 13.01 and 9.27. An average probing depth of 1.95 was recorded at sites facing the natural root surface (group A), whereas, at sites facing the area of tooth preparation for caries removal (group B), the average PD was 2.57.

Three months afterward (step 3), FMPS and FMBS were 11.48 and 7.48. An average PD of 1.66 and 2.21.

Inflammatory infiltrate was mainly composed of macrophages, lymphocytes, and mastocytes, whereas polymorpho-nuclear leukocytes were found less frequently. In the 29 treated subjects, the average grade was 3.71, in group A, and 3.83 in group B. Difference in inflammation grade between groups A and B was not statistically significant (P = 0.36, Mann-Whitney).

Discussion

in the discussion section it is pointed out that the probing depth was significantly reduced from baseline to follow-up measurements in both group A and group B as well as for PD recorded at the most apical site of the restorations. the authors suggest that the statistically significant PD improvement demonstrates that well-shaped and well-refined subgingival restorations are compatible with soft-tissue health similar to natural root surfaces.

than it is added that also the inflammation level revealed by the histological analysis was similar in the control gingiva (group A) and treatment gingiva (group B). The histologic findings could also corroborate the clinical outcomes of the research supporting the conclusion that the inflammation response of tissues surrounding composite restorations is similar to that of tissues surrounding the teeth. 

Conclusion

The article concludes assessing that, within the limitation of the research, subgingival restorations result compatible with gingival health, provided that biological width was respected and a stringent supportive therapy could be performed.

For additional information: Clinical and histological reaction of periodontal tissues to subgingival resin composite restorations