Alveolar bone thickness overlying healthy maxillary and mandibular teeth: A systematic review and meta-analysis

To systematically review and meta-analyse the Alveolar Bone Thickness (ABT) overlying healthy teeth. The secondary objective was to review the association of ABT with gender, age, and smoking. The PubMed, Embase, Scopus, ProQuest, Web of Science, and Cochrane Library databases were searched up to July 2020. English articles (sample size ≥ 10) which had used CT or CBCT to measure the ABT at clearly defined reference points were included. The maximum likelihood approach meta-analysis was used to estimate the means (95% CIs). A total of 68 articles were included. The meta-analysis results were as follows: In the anterior maxilla, the mean labial plate thickness ranged from 0.42–1.75 mm, while it was thicker for the posterior teeth (0.78–4.31 mm). The palatal plate thickness ranged from 0.97–8.13 mm. In the anterior mandible, the thickness of labial and lingual plates ranged from 0.4–3.71 mm and 0.38–5.44 mm, respectively. The alveolar bone was thicker for the posterior teeth both at the labial (0.66–6.31 mm) and lingual (2.31–7.77 mm) sides. Meta-regression revealed a significant relationship between gender and ABT at several points. There was a controversy regarding the association of ABT with age. No significant difference was evidenced between smokers and non-smokers. This study presents a clear image of the alveolar bone structure. Since it has pooled ABT values from various populations, outcomes could be acknowledged as global averages. Therefore, it could provide perspective for several dental procedures, including orthodontic treatments and immediate implant placement.