Microscopic in-situ analysis of the mucosal healing around implants treated by protease activated receptor 4-agonist peptide or perpendicularly protruded type I collagen in rats.

Enhanced mucosal sealing around titanium implants can reduce complications such as peri-implantitis. The present study aims to investigate the mucosal healing at the early stage around the protease activated receptor 4-agonist peptide (PAR4-AP)- or perpendicularly protruded type I collagen (pCol)-treated titanium implants. A total of 72 implants were placed in 36 rats in the study. Following extractions, two tissue-level implants among the following three different surfaces, PAR4-AP-coated (PAR4 group, n = 24), pCol-treated (pCol group, n = 24) and non-treated (control group, n = 24) ones, were placed in the maxillae of each rat based on a split-mouth design. The specimens retrieved at 8 h (n = 8 per group), 3 days (n = 8 per group), and 2 weeks (n = 8 per group), were immunostained and tissue-cleared, and the signals of laminin-5 and collagen fibers were observed under multiphoton microscopy. Statistical analyses were performed using linear mixed model with post hoc tests to compare differences between the groups. While there was no intergroup difference at 8 h, the laminin-5 at 3 days was more abundant near the PAR4-group-surface, and its area was significantly larger in the PAR4 group (0.0204 ± 0.0194 mm2 ) than the control (0.0019 ± 0.0025 mm2 , p = .001) and pCol (0.0023 ± 0.0022 mm2 , p < .001) groups. The pCol group showed a significantly larger area of collagen fibers (0.0230 ± 0.0148 mm2 ) compared to the control (0.0035 ± 0.0051 mm2 , p = .002) and PAR4 (0.0031 ± 0.0057 mm2 , p < .001) groups at 3 days. At 3 days and 2 weeks, the collagen fiber orientation of the pCol group showed a more perpendicular manner compared to the control and PAR4 groups. The signal of basal lamina and collagen fibers were stronger around the PAR4-AP- and pCol-treated titanium surfaces, respectively during the early healing stage. This could have implications for improved mucosal sealing around dental implants, potentially reducing complications such as peri-implantitis.

The In Vitro Evaluation of Preosteoblast Migration From 3-D-printed Scaffolds to Decontaminated Smooth and Minimally Rough Titanium Surfaces: A Pilot Study.

In vitro evaluations are essential to gaining a better understanding of re-osseointegration, while reducing animal use and the overall costs of peri-implantitis studies. This pilot study evaluated preosteoblast migration from 3-D-printed scaffolds to decontaminated titanium microimplants, creating a system that tries to mimic the bone-implant interface. Smooth (S) and minimally rough (R) titanium microimplants were incubated in Escherichia coli cultures and divided into six groups according to the decontamination protocol applied: EDTA gel (EDTA); chlorhexidine (CHL); chlorhexidine-soaked gauze (GCHL); scaling (SC); titanium brush (TiB); and implantoplasty (IP). Pristine S and R microimplants were used as the controls (C). After the decontamination procedures, the microimplants were inserted in 3-D-printed polyurethane-based scaffolds previously inoculated with preosteoblast cell cultures. Cellular migration was assessed after 24, 72 and 120 hours by ATP quantification. At the 120-hour time point, there was no statistically significant difference between S-C, S-EDTA, S-CHL, S-GCHL and S-SC (p > 0.05), and between R-C, R-EDTA and R-GCHL (p > 0.05). The in vitro model developed in this pilot study successfully demonstrated cell migration on the different decontaminated surfaces. This methodology suggests that on smooth microimplants, EDTA, GCHL, SC and TiB decontamination may have a reduced impact on preosteoblast migration, while on minimally rough microimplants, EDTA and GCHL decontamination affected cell migration the least. However, when selecting a decontamination protocol, the effectiveness of the decontamination per se must also be considered.

Peri-implant Mucosal Tissues and Inflammation: Clinical Implications.

PURPOSE: The purpose of this review was to explore the available literature and compile studies that discuss the relevance of the biofilm, onset and progression of disease, critical peri-implant pocket depth, frequency of supportive implant therapy, excess cement, and keratinized peri-implant tissues as related to peri-implant disease. MATERIALS AND METHODS: PubMed, Cochrane Oral Health Group Specialized Trial Register, and hand searches of related journals were performed in relationship to the focused question. Reports describing techniques, preclinical studies, and case reports were excluded. RESULTS: Due to the absence of controlled studies, a meta-analysis could not be performed. Summaries of relevant publications were completed for each topic area. Clinical recommendations were developed to provide guidance to the practitioner. CONCLUSION: The importance of proper diagnosis, planning, and clinical treatment cannot be overstated. Patient factors including systemic disease, periodontal status, and oral hygiene significantly impact peri-implant health. Clinician factors such as implant position, excess cement, and restorative design can contribute to development of peri-implant disease. Surveillance of implant status is essential and can be assisted by the assessment of risk factors, establishment of a proper recall program, and monitoring changes in bone and peri-implant pocket depths.

Alveolar Ridge Augmentation with Three-Dimensional Printed Hydroxyapatite Devices: A Preclinical Study.

The objective of this study was to evaluate the effectiveness of precise three-dimensional hydroxyapatite printed micro- and macrochannel devices for alveolar ridge augmentation in a canine model. All grafts induced minimal inflammatory and fibrotic reactions. Examination of undecalcified sections revealed that both types of grafts demonstrated bone ingrowth. The majority of the bone growth into the block graft was into the channels, though a portion grew directly into the construct in the form of small bony spicules. In conclusion, bone ingrowth was readily demonstrated in the middle of the implanted printed devices.