Maxillary bone characteristics between thick and thin gingival biotypes with dentoalveolar protrusion

The Accuracy of Lateral Cephalogram for Measuring Alveolar Bone Thickness and Root Diameter on Mandibular Incisors

Background: The objective of the study was to ascertain whether the alveolar bone and root of the mandibular central incisor measured from cephalograms can represent the same measurements of both mandibular central and lateral incisors from CBCT. Methods: A total of 38 sets of CBCT images and cephalograms before treatment were selected for this study. Thicknesses included alveolar bone, cortical bone, and cancellous bone at the labial and lingual sides. Root diameter and total root-bone thickness were also evaluated. The measurements were performed at 3, 6, and 9 mm from the cemento-enamel junction. Heights included labial bone height and lingual bone height. All measurements were performed on cephalograms and CBCT images of the mandibular central incisor (L1CT) and mandibular lateral incisor (L2CT). The data were statistically analyzed using one-way ANOVA and Bonferroni tests (p < 0.01) to compare the cephalograms, L1CT, and L2CT. Results: The cephalograms presented thicker alveolar bone and cortical bone (labial: 0.16−0.31 mm, lingual: 0.14−0.29 mm; p < 0.001) as well as higher alveolar crest (labial: 0.46−0.48 mm, lingual: 0.38−0.39 mm; p < 0.001) than the CBCT images on both the labial and lingual sides, whereas lingual cancellous thicknesses were not significantly different (p = 0.257). The cephalograms presented greater total root-bone thicknesses than L1CT (0.19−0.30 mm; p < 0.001), whereas the cephalograms traced thinner roots than L1CT (0.18−0.23 mm; p < 0.001) and L2CT (0.39−0.59 mm; p < 0.001). Conclusion: Lateral cephalograms cannot represent both mandibular central and lateral incisor dentoalveolar thicknesses, heights, and root diameters the same as CBCT. However, the differences were less than 0.5 mm.

The Accuracy of Lateral Cephalogram in Representing the Anterior Maxillary Dentoalveolar Position

Background: To evaluate the dentoalveolar position and root diameters of the maxillary incisors from cone beam computed tomograms (CBCT) compared with cephalometric tracings. Methods: A total of 64 sets of initial lateral cephalograms and CBCT images were enrolled. Measurements of dentoalveolar position included bone thicknesses and heights of alveolar, cortical, and cancellous bone. Root diameter and total root-bone thickness were also evaluated. All measurements were performed on cephalograms and CBCT images of the maxillary central incisor (U1CT) and maxillary lateral incisor (U2CT). The data were statistically analyzed using one-way ANOVA and Bonferroni tests (p < 0.01) to compare the cephalograms, U1CT, and U2CT. Results: The cephalograms presented thicker alveolar bone (labial: 0.20−0.67 mm, palatal: 0.41−0.60 mm; p < 0.001) and cortical bone (labial: 0.20−0.67 mm, palatal: 0.41−0.52 mm; p < 0.001) as well as higher alveolar crest (labial: 0.23−0.27 mm, palatal: 0.15−0.17 mm; p < 0.001) and cortical height (labial: 0.35−0.47 mm; p = 0.051, palatal: 0.14−0.18 mm; p < 0.001) than the CBCT images on both the labial and palatal sides, whereas palatal cancellous thickness was not significantly greater (p > 0.01). The cephalograms presented a greater total root-bone thicknesses (0.80−1.08 mm; p < 0.001), whereas the cephalograms traced thinner roots than the CBCT images (0.36−0.52 mm; p < 0.01). Conclusion: Routine lateral cephalograms are not suitable for alveolar bone evaluation in orthodontic treatment due to errors in representing dentoalveolar thicknesses and heights.

Evaluation of the association between gingival phenotype and alveolar bone thickness: A systematic review and meta-analysis

OBJECTIVE

To conduct a systematic review and meta-analysis of studies that evaluated the association between gingival phenotype (GP) and the underlying alveolar bone thickness (ABT).

DESIGN

An electronic search was performed in PubMed, Embase, Scopus, ProQuest, and Web of Science. The following inclusion criteria were applied: English original studies that compared the ABT in periodontally healthy patients presenting thin versus thick GPs. Studies that evaluated the correlation between gingival thickness (GT) and ABT were also included. Pooled mean difference (95% confidence interval) was estimated using random-effects maximum likelihood model meta-analysis.

RESULTS

From a total of 1427 retrieved articles, 17 were included. The majority of eight studies that compared the ABT between thick and thin GPs, reported a significantly greater ABT associated with a thick phenotype. Based on the meta-analysis results of six studies, the mean difference between the two phenotypes (0.33 mm) was statistically significant (P < 0.01). The majority of ten studies that investigated the correlation between GT and ABT evidenced a significant positive correlation (r = 0.11 -0.49). The association was more evident in the crestal areas and decreased toward the apex.

CONCLUSIONS

There is contradictory evidence concerning the correlation between soft and hard tissue thickness; however, the meta-analysis revealed a significantly thicker alveolar plate in the presence of a thick phenotype. Since the evaluation of GP could be simply performed using a periodontal probe, such a relationship could provide clinical perspective at the initial examination. This is particularly beneficial in procedures affecting periodontal structures, including immediate implant placement and orthodontic treatments.