Buccal soft tissue dehiscence defects at dental implants-associated factors and frequency of occurrence: A systematic review and meta-analysis

Aim To identify the factors associated with buccal peri-implant soft tissue dehiscences (BSTDs) and their frequency of occurrence. Materials and Methods Randomized controlled trials, controlled clinical trials, cohort studies, and case series assessing the frequency of occurrence of BSTD were included. BSTD was defined as an apical migration of the peri-implant soft tissues of >= 1 mm from the baseline examination (final restoration) or in comparison with the adjacent or contralateral natural tooth. Frequency distributions of BSTD related to the presence or absence of any surgical, prosthetic, or anatomic factor that may have contributed to the development of BSTD were recorded. Random-effects meta-analyses using odds ratios (OR) were performed to investigate the association of certain factors with the development of BSTD. Results Twenty-four articles were finally included belonging to 22 clinical investigations. Patients at higher risk of developing BSTD were associated with thin biotype (OR = 2.85 [1.40, 5.8], n = 5, p = .003) and with buccally placed implants (OR = 14.37 [4.58, 45.14], n = 3, p <= .001). Patients without connective tissue grafting (CTG) had greater odds of developing BSTD (OR = 9.00 [3.11, 26.02], n = 5, p <= .001), while buccal bone plate thickness of <1 mm and immediately placed implants were not associated with greater BSTD (OR = 1.29 [0.35, 4.77], n = 2, p = .704 and OR = 1.56 [0.46, 5.26], n = 4, p = .477, respectively). The frequency of occurrence of BSTD varied across the included studies with a range from 0% to 61%. Conclusions Thin tissue biotype and buccally placed implants were associated with BSTD, whereas CTG seemed to have a protective effect. Thin buccal plates and immediately placed implants did not demonstrate a higher risk of BSTD.