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 study aimed to systematically review the FAB thickness 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 from the Cochrane Collaboration. A meta-analysis of single means, subgroup analysis and meta-regression of covariates were conducted.Results: Twenty-nine studies, including 17,321 teeth, were selected. 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 and females exhibited a thinner FAB at some apico-coronal locations of maxillary incisors and canines. Thicker gingival phenotypes were associated with a thicker FAB in maxillary incisors and canines. The geographical setting proved to be 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. The prevalence of bone dehiscences at maxillary incisors and canines was 12.3-20.1%; while the prevalence of fenestrations was between 6.4% and 23.8%.Conclusions: Facial alveolar bone is thin, heterogeneous in width along its apico-coronal dimensions, and increases in thickness in maxillary premolars. The prevalence of < 1 mm FAB thickness was 69.9% in central incisors, 64.5% in lateral incisors, 55% in canines and 40.4% at first premolars. The CEJ-bone crest distance presented homogeneous and similar values in all teeth analyzed.

Effect of the buccal gap width following immediate implant placement on the buccal bone wall: A retrospective cone‐beam computed tomography analysis

“…The width and height of the alveolar process and basal bone at the upper central incisors differ anatomically from the corresponding structures at upper lateral incisors and canines. 24,26,27 Botelho and colleagues 26 described the anatomical features of 174 healthy maxillary central and lateral incisors, and canines. The authors observed that the alveolar process at the central incisor region was significantly wider and longer than at lateral incisors but narrower and shorter than at the canine region.…”

“…There is a significant anatomical difference between premolar and anterior sites, especially regarding the thickness of the buccal bone wall. [22][23][24] A recent systematic review reported that, in premolar sites, the thickness of the buccal wall is greater than 1 mm (1.09-1.96) while at central incisor sites the corresponding value is markedly reduced, about 0.8 mm. 24 Thus, it is plausible to suggest that the healing of a grafted gap would be better protected by the thicker buccal wall at the premolar sites than by the thin buccal wall at the central incisor sites, which would have promoted superior bone formation.…”

Use of fan beam computerized tomography and cone beam computerized tomography in oral and maxillofacial surgery and its indications: A literature review

“…Despite being the gold standard in the evaluation of hard tissues, CBCT is incapable of recording soft structures, and there is also difficulty in locating anatomical structures, making correct visualization difficult and may generate little precision for locating these structures in the generated image [1,17].…”

“…In this regard, it is necessary to identify ideal situations for the use of cone beam or fan beam techniques, knowing the specific indication for each one and its applicability, its advantages and disadvantages [14,15,16,17], in addition to a comparison between Cone Beam Computed Tomography and Spiral Computed Tomography in the field of dentistry regarding Oral and Maxillofacial Surgery and Traumatology [9].…”

Analysis of the sagittal root angle and its correlation with hard and soft tissue indices in anterior teeth for immediate implant evaluation: a retrospective study

“…The ideal implant axis is proposed to correspond to the axis of the contralateral and adjacent tooth inside the alveolar bone, and the implant is inclined to palatal [8,9]. Limited by insufficient bone dimensions around the tooth root, especially on the labial side, the root apex, and a thin gingiva phenotype, it is hard to place an implant following the axis of the contralateral corresponding tooth, as bone fenestration and dehiscence may occur [10][11][12]. Thus, a pre-implantation evaluation of the root angle, accounting for the characteristics of the surrounding implant-related hard and soft tissues, is crucial for planning an immediate implant placement.…”