Facial alveolar bone thickness and modifying factors of anterior maxillary teeth: a systematic review and meta-analysis of cone-beam computed tomography studies

Abstract

Background Understanding the anatomy of the facial alveolar bone (FAB), provides a prognostic tool for estimating the degree of dimensional ridge alterations after tooth extraction. This systematic review and meta-analysis aims to determine the FAB thickness and modifying factors of anterior maxillary teeth measured by CBCT scans. A secondary objective was to assess the facial distance from the cementoenamel junction (CEJ) to the bone crest. Methods An electronic search was made of Medline, Embase, Web of Science, Cochrane Library and Google Scholar up to December 2019. Studies that analyze and quantitatively compare FAB thickness at maxillary teeth by CBCT scans were included. The methodological quality of the included studies was appraised using the ROBINS-I tool and the overall meta-evidence certainty using the GRADE approach. A single means random-effects meta-analysis was performed to obtain the weighted mean for 95% confidence interval. A meta-regression of covariates and subgroup analysis was conducted. The nullity Qh test and I2 index for heterogeneity was estimated. Results 2560 potentially relevant articles were recorded from which 29 studies were selected for the qualitative analysis, including 17,321 teeth. Seventeen studies considered the facial bone crest, and 12 the CEJ as a reference point for their measurements. Mean FAB thickness was ≤ 1 mm in maxillary incisors and canines (0.75–1.05 mm) and 1–2 mm in premolars. Patients over 50 years of age, females and thin gingival phenotype was associated with thinner FAB at some apico-coronal locations of maxillary incisors and canines. The geographical setting was an effect modifier that could explain up to 87% of the heterogeneity in FAB thickness, being Asian populations that showed the lowest FAB thickness values. The CEJ-bone crest distance was 2–2.5 mm in all teeth analyzed. Population over 50 years of age exhibited greater CEJ-bone crest distances, and males also showed a trend for greater distance. Evidence certainty has shown moderate quality in most analysis subsets. Conclusions Facial alveolar bone at anterior maxillary teeth is thin, heterogeneous in width along its apico-coronal dimensions, and increases in thickness in maxillary premolars. The CEJ-bone crest distance presented homogeneous and similar values in all teeth analyzed.

Relationship between different skeletal facial types and anterior alveolar bone thickness with cone-beam computed tomography in an Asian population

“…A systematic review showed that geographic environment was an effective modifier that explained the reason for up to 87% of alveolar bone thickness heterogeneity. Asians have thinner anterior alveolar bones than Europeans ( 22 ). The thinner alveolar bones of Asian populations made the difference between these three groups not detectable.…”

Dimensional Changes in the Alveolus after a Combination of Immediate Postextraction Implant and Connective Grafting and/or Socket Shield Technique

“…The preoperative state was compared with the immediate postoperative condition, and the outcome after year, both overall and compared with taking the graft and/or SST. Since the thickness of the peri-implant tissues varies throughout the vertical axis [ 30 , 31 ], measurements were taken at 3, 5, and 7 mm from the gingival margin. The implant platform was used as a reference point measuring changes in alveolar crest height.…”

“…Alveolar resorption occurs more markedly in a horizontal dimension, followed by vertical changes in medial buccal and medial lingual areas. Buccal cortical thickness is related to the degree of resorption after tooth extraction, the greater thickness being a protective factor for bone remodeling [ 30 , 40 , 42 , 43 ].…”

“…According to a recent meta-analysis study, the mean buccal cortical thickness in maxillary incisors and canine teeth is ≤1 mm, and in maxillary premolars, 1–2 mm [ 30 ]. Our results are in line with this finding ( Table 4 ).…”

Avoiding errors and complications related to immediate implant placement in the esthetic area with a mucogingival approach

“…Bone thickness of 1.8-2 mm on the buccal aspect of dental implants has been suggested to ensure predictable long-term stability of the hard and soft tissues. 44,47 However, according to several studies, [48][49][50] the reported buccal bone thickness in the maxillary anterior region-as measured by computed tomography in healthy patients-is frequently less than 1 mm in as many as 74% of cases. In addition, as a consequence of postextraction alveolar remodeling, the mean changes in horizontal bone dimensions at immediate implant sites in the maxillary esthetic zone amount to nearly 0.7 mm.…”