Clinical efficacy of intraoral ultrasonography versus transgingival probing for measurement of gingival thickness in different gingival biotypes: a clinical trial.

BACKGROUND: Transgingival probing is conventionally used for gingival thickness (GT) measurement. However, invasiveness is a major drawback of transgingival probing. Thus, researchers have been in search of alternative methods for measurement of GT. This study compared the clinical efficacy of intraoral ultrasonography and transgingival probing for measurement of GT in different biotypes. MATERIALS AND METHODS: This clinical trial was conducted on 34 patients requiring crown lengthening surgery. GT was measured at 40 points with 2- and 4-mm distances from the free gingival margin (FGM) of anterior and premolar teeth of both jaws in each patient by an intraoral ultrasound probe. For measurement of GT by the transgingival probing method, infiltration anesthesia was induced, and a #25 finger spreader (25 mm) was vertically inserted into the soft tissue until contacting bone. The inserted length was measured by a digital caliper with 0.01 mm accuracy. All measurements were made by an operator with high reliability under the supervision of a radiologist. Data were analyzed by t-test, Power and Effect Size formula, and intraclass correlation coefficient (ICC). RESULTS: The two methods were significantly different in measurement of GT in both thick and thin biotypes at 2- and 4-mm distances (P < 0.001). The two methods had a significant difference in both the mandible (P < 0.001) and maxilla (P < 0.001) and in both the anterior (P < 0.003) and premolar (P < 0.003) regions. Although the difference was statistically significant in t-tests, the power and effect formula proved it to be clinically insignificant. Also, the ICC of the two methods revealed excellent agreement. CONCLUSION: The results showed optimal agreement of ultrasound and transgingival probing for measurement of GT. TRIAL REGISTRATION: The study was approved by the ethics committee of Shahid Beheshti University of Medical Sciences on 2021-12-28 (IR.SBMU.DRC.REC.1400.138) and registered in the Iranian Registry of Clinical Trials on 2022-03-14 (IRCT20211229053566N1).

Morphological Variations of the Posterior Mandible: Proposing a Classification for Ridge Morphology Based on Cone-Beam Computed Tomography Data.

This study sought to assess the morphological variations of the posterior mandible and propose a classification for ridge morphology based on cone-beam computed tomography (CBCT) data. This retrospective, cross-sectional study evaluated 130 CBCT scans of patients with edentulous mandibles. Qualitative variables including lingual and crestal concavity, vertical, horizontal and angular limitations, and ridge morphology were assessed at 631 sites on CBCT scans of 87 males and 43 females. A classification for ridge morphology in the posterior mandible was proposed based on the collected data. The kappa coefficient was calculated to assess the intra-observer agreement, and data were analyzed using the chi-square test and Pearson's correlation test. The frequency of lingual concavity increased from the anterior towards the posterior region relative to the mental foramen (P < 0.05). The maximum frequency of lingual concavity (11.1%) was noted at 21 mm distance from the mental foramen while its minimum frequency (4.1%) was noted at 5 mm from the mental foramen (P < 0.05). Ridge morphology, defined as ridge angulation < 15°, no lingual or crestal concavity, no limitation in width, and 8-10 mm height, had the highest frequency. Its suggested treatment plan included a 10-mm implant without width limitation or severe angulation. The majority of common morphologies had no width limitation with ridge angulation < 15°. Height limitation was only present in two of them, which can be resolved by placement of a short implant or ridge augmentation.

Variations in bone quantity in the posterior mandible: a cross-sectional cone beam computed tomographic study.

In this retrospective cross-sectional study, cone beam computed tomography (CBCT) was used to assess the bone quantity variations in the posterior mandible of edentulous patients. The crestal cortical bone thickness, buccal cortical bone thickness, lingual cortical bone thickness, ridge height, ridge width, ridge angle, lingual concavity depth, and cortical to cancellous bone surface area ratio were measured at 631 sites on 130 CBCT scans of edentulous patients. The patient sample comprised 87 men and 43 women with a mean (SD) age of 63.0 (11.8) years. One calibrated observer made all of the measurements. The intraobserver agreement was calculated, and the results of the measurements were analyzed with the independent t test and Pearson correlation test. The crestal, buccal, and lingual cortical bone thickness and ridge angle decreased significantly with age, while the ridge width increased significantly with age (P < 0.05). The buccal and lingual cortical bone thickness, ridge height, ridge angle, and lingual concavity depth were significantly greater in men (P < 0.05). The buccal cortical bone thickness, ridge width, ridge angle, and lingual concavity depth increased significantly from the anterior toward the posterior region relative to the mental foramen (P < 0.05). A ridge height of greater than 8.0 mm, a ridge width of greater than 6.0 mm, and a ridge angle of less than 15° were noted in 74%, 80%, and 80% of the sites, respectively (P < 0.05). The anatomical variations found in the mandibular posterior region of edentulous patients necessitate comprehensive CBCT assessment prior to implant placement in this area.