Digital three-dimensional visualization of intrabony periodontal defects for regenerative surgical treatment planning

BACKGROUND: In the regenerative treatment of intrabony periodontal defects, surgical strategies are primarily determined by defect morphologies. In certain cases, however, direct clinical measurements and intraoral radiographs do not provide sufficient information on defect morphologies. Therefore, the application of cone-beam computed tomography (CBCT) has been proposed in specific cases. 3D virtual models reconstructed with automatic thresholding algorithms have already been used for diagnostic purposes. The aim of this study was to utilize 3D virtual models, generated with a semi-automatic segmentation method, for the treatment planning of minimally invasive periodontal surgeries and to evaluate the accuracy of the virtual models, by comparing digital measurements to direct intrasurgical measurements. METHODS: Four patients with a total of six intrabony periodontal defects were enrolled in the present study. Two months following initial periodontal treatment, a CBCT scan was taken. The novel semi-automatic segmentation method was performed in an open-source medical image processing software (3D Slicer) to acquire virtual 3D models of alveolar and dental structures. Intrasurgical and digital measurements were taken, and results were compared to validate the accuracy of the digital models. Defect characteristics were determined prior to surgery with conventional diagnostic methods and 3D virtual models. Diagnostic assessments were compared to the actual defect morphology during surgery. RESULTS: Differences between intrasurgical and digital measurements in depth and width of intrabony components of periodontal defects averaged 0.31 ± 0.21 mm and 0.41 ± 0.44 mm, respectively. In five out of six cases, defect characteristics could not be assessed precisely with direct clinical measurements and intraoral radiographs. 3D models generated with the presented semi-automatic segmentation method depicted the defect characteristics correctly in all six cases. CONCLUSION: It can be concluded that 3D virtual models acquired with the described semi-automatic segmentation method provide accurate information on intrabony periodontal defect morphologies, thus influencing the treatment strategy. Within the limitations of this study, models were found to be accurate; however, further investigation with a standardized validation process on a large number of participants has to be conducted

Vascular survey of the maxillary vestibule and gingiva-clinical impact on incision and flap design in periodontal and implant surgeries.

OBJECTIVES Currently, empirical clinical findings on the blood supply of the maxillary vestibule are not backed up with sufficient literature. The purpose of this study was to investigate the mucosal and periosteal vascular supply in the maxillary vestibule macroscopically and radiographically to improve surgical strategies and flap designs. MATERIALS AND METHODS Thirty head corpses were selected (9 dentate, 11 partially edentulous, 10 edentulous). Twenty-six corpses were injected by red latex milk and embalmed with Thiel solution. Four cadavers were prepared for corrosion casting. Arterial path and anastomoses in the maxillary vestibule of dentate, partially edentulous and edentulous ridges, were analyzed macroscopically and by computed tomography (CT). RESULTS Transverse periosteomucosal anastomoses were detected in the posterior and esthetic zones of the maxillary vestibule. The buccal branches penetrated the interdental septum toward the palate. In the esthetic zone, superior labial artery (SLA) supplied the mucosa and the infraorbital artery (IOA) supplied the periosteum. Corrosion casting showed anastomoses between IOA and nasal septal branches. CT analysis revealed ipsilateral and contralateral anastomoses between SLA and IOA. In dentate ridges, mucosal star-shaped terminal branches were detected. CONCLUSIONS The macroscopic and radiographic vascular survey analysis revealed the anatomical background behind several clinically documented phenomena related to oral and periodontal surgeries. CLINICAL RELEVANCE This study permits clinicians to design less invasive flaps when releasing incisions in the maxillary vestibule during periodontal and implant surgeries. Our observations strongly point to the significance of an undamaged periosteum to prevent compromised flap revascularization and wound healing disturbances

Three‑dimensional volumetric assessment of hard tissue alterations following horizontal guided bone regeneration using a split‑thickness flap design: A case series

Objectives: To analyze morphological, volumetric, and linear hard tissue changes following horizontal ridge augmentation using a three-dimensional radiographic method. Methods: As part of a larger ongoing prospective study, 10 lower lateral surgical sites were selected for evaluation. Horizontal ridge deficiencies were treated with guided bone regeneration (GBR) using a split-thickness flap design and a resorbable collagen barrier membrane. Following the segmentation of baseline and 6-month follow-up conebeam computed tomography scans, volumetric, linear, and morphological hard tissue changes and the efficacy of the augmentation were assessed (expressed by the volume-to-surface ratio). Results: Volumetric hard tissue gain averaged 605.32 ± 380.68 mm3.An average of 238.48 ± 127.82 mm3 hard tissue loss was also detected at the lingual aspect of the surgical area. Horizontal hard tissue gain averaged 3.00 ± 1.45 mm. Midcrestal vertical hard tissue loss averaged 1.18 ± 0.81 mm. The volume-to-surface ratio averaged 1.19 ± 0.52 mm3/mm2. The three-dimensional analysis showed slight lingual or crestal hard tissue resorption in all cases. In certain instances, the greatest extent of hard tissue gain was observed 2–3 mm apical to the initial level of the marginal crest. Conclusions: With the applied method, previously unreported aspects of hard tissue changes following horizontal GBR could be examined. Midcrestal bone resorption was demonstrated, most likely caused by increased osteoclast activity following the elevation of the periosteum. The volume-to-surface ratio expressed the efficacy of the procedure independent of the size of the surgical area