The aim of this study was to compare the topographical, chemical and osseointegration characteristics of sandblasting and acid-etching (SLA) surfaces and dental implants treated by boron compounds. Titanium (Ti) disks (n = 20) were modified using boron (B) and boric acid (H₃BO₃) and then compared with the conventional SLA surface via surface topographic characterizations. Dental implants (3.5 mm in diameter and 8 mm in length) with the experimental surfaces (n = 96) were inserted into the tibias of six sheep, which were left to heal for 3 and 7 weeks. Histologic, histomorphometric (bone–implant contact (BIC%)) and mechanical tests (removal torque value (RTV)) were performed. The boron-coated surface (BC group) was smoother (Rz: 4.51 μm ± 0.13) than the SLA (5.86 μm ± 0.80) and the SLA-B (5.75 μm ± 0.64) groups (p = 0.033). After 3 weeks, the highest mean RTV was found in the SLA group (37 N/cm ± 2.87), and the difference compared with the BC group (30 N/cm ± 2.60) was statistically significant (p = 0.004). After 7 weeks, the mean RTV was >80 N/cm in all groups; the highest was measured in the H₃BO₃-treated (BS) group (89 N/cm ± 1.53) (p < 0.0001). No statistically significant differences were found in the BIC%s during both healing periods between the groups. H₃BO₃ seems to be a promising medium for dental implant osseointegration.

Background: This study aimed to evaluate the effects of tetracalcium phosphate (TTCP) graft material on the stability and osseointegration of dental implants placed in anatomically compromised bone. Materials and Methods: Six healthy sheep were used following ethical approval. Osteotomies were created in the tibial region and divided into three groups: Group A (control, n = 12) with standard osteotomy; Group B (n = 12) with enlarged and deepened osteotomy; and Group C (n = 36), where osteotomy sites were filled with TTCP prior to implant placement. Implant stability was measured using the resonance frequency analysis (RFA), and osseointegration was evaluated histologically by bone-to-implant contact percentage (BIC%). Animals were sacrificed at the 3rd and 6th weeks for histological analysis. Results: Initial RFA values exceeded 42.5 in all groups. Group C demonstrated the highest RFA at Week 6 (79) and significantly higher RFA values at Week 3 compared to other groups, while Group B consistently showed the lowest stability. At Week 3, Group A exhibited the highest BIC% (28.04 ± 5.05%). By Week 6, BIC% increased in all groups, with no significant intergroup differences. Robust ANOVA revealed significant effects of time and group on both RFA and BIC%. Conclusions: TTCP significantly enhanced implant stability and osseointegration in compromised bone, providing improved secondary stability and suggesting its potential clinical benefit in challenging anatomical conditions.

Background/Objectives: Radiotherapy is a cornerstone of head and neck cancer treatment, but it can adversely affect periodontal tissues by impairing vascularity, cellularity, and healing capacity. The present study aimed to histologically and immunohistochemically evaluate radiotherapy-induced changes in periodontal tissues in a rat model of experimental periodontitis, with particular focus on periodontal ligament width (PerioW) and the RANK/RANKL/OPG axis at different healing stages. Methods: Seventy-two male Sprague–Dawley rats were allocated to three groups: irradiation only (Rt), ligature-induced periodontitis only (Pt), and ligature-induced periodontitis followed by irradiation (PtRt). Experimental periodontitis was induced by placing ligatures around the maxillary first molars for two weeks. On the day of ligature removal, the irradiated groups received a single 20 Gy dose to the head and neck region. Animals were euthanized on days 1, 15, and 30 after ligature removal (n = 8/group/time point). Histomorphometric analysis of PerioW was performed on H&E-stained sections, and immunohistochemical staining was used to quantify RANK, RANKL, and OPG expression. Results: On day 1, PerioW did not differ significantly among groups, although the PtRt group had the highest mean. A significant intergroup difference was observed for RANKL, with higher expression in PtRt than in Pt. On day 15, PerioW differed significantly among groups, with the lowest value in Rt and the highest in PtRt; the Rt–PtRt comparison was significant. At this time point, RANK, RANKL, OPG, and the RANKL/OPG ratio showed no significant intergroup differences. On day 30, no significant intergroup differences were found for PerioW or immunohistochemical parameters; however, PtRt continued to show the highest PerioW and OPG values and the lowest RANKL/OPG ratio. Conclusions: Radiotherapy superimposed on periodontitis enhanced early pro-resorptive signaling and delayed structural normalization of periodontal tissues. Although late increases in OPG suggested a compensatory response, this appeared insufficient to fully reverse radiation-associated periodontal alterations. These findings support the importance of controlling periodontal inflammation before radiotherapy to reduce subsequent periodontal tissue damage.