Is Periodontal and Peri- Implant Disease Associated with Fixed Partial Denture Use? A 25-year Prospective Case Series.

INTRODUCTION: The association of the periodontium with the fixed prosthesis is the basis of prosthetic rehabilitation. This prospective case series aimed to evaluate periodontal health through the relation between periodontal/peri-implant disease progression and the use of fixed partial dentures (FPDs). METHODS: Probing depth (PD), clinical attachment level (CAL), gingival index (GI), and plaque index (PI) on either teeth or implants were evaluated at up to 25-year follow-up and compared with the baseline. Statistical analysis was performed using the Kaplan-Meier test (p⟨0.05). RESULTS: The prospective evaluation showed that the patients maintained adequate periodontal health. Failure (severe periodontal stages) occurred in 12.5% of patients. The survival rate for 107 teeth/implants was 80.48%. The comparisons for clinical parameters revealed no statistically significant difference (p⟩ 0.05). At T1, the measurements for anterior and posterior regions, respectively, were PD =2.7mm and 3.1mm; CAL= 3.3mm and 3.6mm; GI=0.5 (both regions); and PI=0.79 and 0.62. Periodontal/peri-implant disease progression did not relate to the use of prostheses. CONCLUSIONS: Patients with more frequent follow-up appointments and lower GI and PI showed periodontal health for longer periods. Patients with different oral hygiene levels present different periodontal disease progression. Periodic hygiene control and motivation are vital factors for extensive oral rehabilitation success.

The combined effects of binder addition and different sintering methods on the mechanical properties of bovine hydroxyapatite.

Hydroxyapatite (HA) from bovine bones has been used as a biomaterial in dentistry due to its biocompatibility and bioactivity. However, dense HA bioceramics still present inadequate properties for applications that require high mechanical performance, such as infrastructure. Microstructural reinforcements and control of ceramic processing steps are methods to improve these shortcomings. The present study assessed the effects of polyvinyl butyral (PVB) addition in combination with two sintering methodologies (2-step and conventional), on the mechanical properties of polycrystalline bovine HA bioceramics. The samples were divided into four groups (with 15 samples per group): conventional sintering with binder (HBC) and without binder (HWC) and 2-step sintering with (HB2) and without binder (HW2). HA was extracted from bovine bones, turned into nanoparticles in a ball mill, and subjected to uniaxial and isostatic pressing into discs, according to ISO 6872 standards. All groups were characterized by x-ray diffractometry (XRD), differential thermal analysis (DTA) and Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and relative density. Besides, mechanical analyses (biaxial flexural strength (BFS) and modulus of elasticity) were also performed. The characterization results demonstrated that adding agglutinants or the sintering method did not affect HA's chemical and structural characteristics. Even so, the HWC group showed the highest mechanical values for BFS and modulus of elasticity being 109.0 (98.0; 117.0) MPa and 105.17 ± 14.65 GPa, respectively. The HA ceramics submitted to conventional sintering and without the addition of binders achieved better mechanical properties than the other groups. The impacts of each variable were discussed and correlated to the final microstructures and mechanical properties.