Prehydrated collagenated cortico-cancellous heterologous bone gel and papillae tunneling for isolated intrabony defects: 12-month noninferiority trial.

OBJECTIVES: This study assessed the effectiveness of prehydrated collagenated xenogenic bone gel and a collagenated cortico-cancellous heterologous bone mixture in conjunction with papillae tunneling techniques (PTT) for treating isolated periodontal intraosseous defects. MATERIALS AND METHODS: Twenty patients with periodontitis stage III/IV and at least one deep isolated interdental 2/3-wall intraosseous defect were included in the study. Surgical incisions were made vertically at the adjacent tooth or horizontally at the mucogingival junction. A full-thickness flap was then carefully lifted under the papillae using special tunneling instruments. The root surfaces were completely cleaned, and the defects were randomly filled with either prehydrated collagenated bone gel (test group; n = 10) or collagenated cortico-cancellous heterologous bone mixture (control group; n = 10). Wounds were closed with microsurgical sutures. We predicted that the lower 95% confidence interval for the difference between the two procedures would exceed a prespecified noninferiority threshold. RESULTS: All wounds closed sufficiently to prevent biomaterial exposure. The test and control groups showed similar mean pocket depth reduction (3.5 ± 1.0 vs. 3.9 ± 1.7 mm; p = 0.52), similar gingival recession (-0.10 ± 0.99 vs. 0.2 ± 0.8 mm; p = 0.46), and similar clinical attachment gain (3.6 ± 1.51 vs. 3.7 ± 1.8 mm; p = 0.89) at the 12-month follow-up. All results were below the noninferiority margin of the sample. CONCLUSIONS: At 12 months, prehydrated collagenous bone gel performed similarly to collagenous heterologous bone granules in the treatment of intraosseous lesions with PTT. In addition, both biomaterials preserved soft tissue with minimal further recession at 1 year. CLINICAL RELEVANCE: When combined with PTT, collagenous xenogeneic bone granules and prehydrated collagenous bone gel achieve comparable clinical outcomes in intrabony defects. The study was registered under the NCT04782921 on ClinicalTrails.

Retentive design of a small surgical guide for implant surgery: An in-vitro study.

OBJECTIVES: Instability of the surgical guide is an overlooked factor that can result in a difference between the planned and the actual positions of an implant. Our aim was to compare the stability of the retentive surgical guide (RSG) with a conventional surgical guide (CSG) in an in-vitro experiment. METHODS: A platform to evaluate the stability of the surgical guide was designed using 3D-modelling software (Meshmixer 3.5, Autodesk). Imaging data from 15 patients with a single missing tooth were used to plan the virtual implant. Two surgical guides were designed (Blue Sky Plan 4.8, Blue Sky Bio) and 3D printed (Form2, Dental SG resin, Formlabs) for each case: the CSG with the default, predetermined software settings, and the RSG, designed on a dental model with a 0.1-mm undercut and altered production parameters (reduced guide-to-teeth offset of 0.07 mm, reduced guide thickness of 2.3 mm and a retentive clasp in a marginal area). The dental models were reproducibly secured on the testing platform using a digital force gauge, and the surgical guides were positioned. An increasing force of 0.1 N, 1 N, 2.5 N, and 5 N was sequentially applied from the buccal and the oral directions to the surgical guide via a drill handle. For each force, either the magnitude of the guide's displacement was captured with an intra-oral scanner (CEREC Omnicam AC, Dentsply Sirona; software version: SW 4.5.2) or the dislodgement of the guide was recorded. Scans were imported for analysis (GOM Inspect 2018, GOM GmbH), and library files of the surgical guides and implants were superimposed as a joined complex. The deviation of the implant's position was calculated from the displacement of the guide's position RESULTS: Three-way repeated measures using ANOVA revealed a more significant guide displacement and virtually projected implant deviation in the CSG group than the RSG group and with increasing force in all the deviation parameters. Both groups showed greater resistance to the displacement with the force applied from the oral direction than the buccal direction. The application of the force in the buccal direction resulted in guide dislodgements of 13% and 0% for the CSG and RSG, respectively. In the oral direction, the dislodgement rates were 33% and 7% for the CSG and RSG, respectively. CONCLUSIONS: Within the limitations of this study, the retentive design increased the stability of the surgical guide and, consequently, the accuracy of the virtually projected implants in comparison to the conventional surgical guide designed using the default settings. Clinical trials are needed to confirm its advantages in clinical use. CLINICAL SIGNIFICANCE: With a simple modification to the design, the surgical guide retention provided greater stability, with smaller deviations under loading; this resulted in improved implant precision parameters without requiring additional materials or software. Further studies are needed to assess the clinical feasibility of this surgical guide with improved retention and function.