Association of crown emergence angle and profile with dental plaque and inflammation at dental implants.

BACKGROUND: The shape of implant restorations is critical for function and aesthetics. It may also be important in peri-implant tissue health preservation. This study aimed to associate the restorative contour of a single crown with marginal dental plaque accumulation, tissue inflammation and probing depths. METHODS: Subjects with a single screw-retained implant restoration were clinically examined. The presence of dental biofilm, tissue inflammation and probing pocket depths were the dependent variables. The emergence angle, profile and depth of the mucosal tunnel were measured on superimposed digital scans of the crown soft-tissue complex, the removed crown mounted on an analogue and the soft tissue. RESULTS: One hundred twenty two subjects (46.7% female, 68.9% never smokers, 77% with treated periodontitis and 52.5% participating in regular supportive peri-implant care) were examined. The emergence angles at the mucosal margin were 15.3 ± 9.4°, 12.7 ± 8.5°, 31.3 ± 11.8° and 19.2 ± 9.8° for the mesial, distal, vestibular and oral aspects of the crowns. The largest emergence profile angles were observed on the vestibular aspect (74.6% of cases), reaching a maximum of 61.7°, and profiles were convex in 59% of cases. Generalized estimating equations indicated that the site-specific platform-level emergence angle and profile and depth of the mucosal tunnel were significantly associated with the presence of detectable plaque accumulation (p < .01) and bleeding on probing (p < .02). CONCLUSIONS: Subtle variations in the shape of the restorative crown are associated with biofilm accumulation and mucosal inflammation. These findings are important for 3D implant planning/positioning and preservation of peri-implant tissue health.

In Vitro and Ex Vivo Kinetic Release Profile of Growth Factors and Cytokines from Leucocyte- and Platelet-Rich Fibrin (L-PRF) Preparations.

L-PRF is an autologous blood-derived biomaterial (ABDB) capable of releasing biologically active agents to promote healing. Little is known about its release profile of growth factors (GFs), cytokines, and MMPs. This study reported the in vitro and ex vivo release kinetics of GFs, cytokines, and MMPs from L-PRF at 6, 24, 72, and 168 h. The in vitro release rates of PDGF, TGF-ß1, EGF, FGF-2, VEGF, and MMPs decreased over time with different rates, while those of IL-1ß, IL-6, TNF-α, IL-8, and IL-10 were low at 6 h and then increased rapidly for up to 24 h and subsequently decreased. Of note, the release rates of the GFs followed first-order kinetics both in vitro and ex vivo. Higher rates of release were found ex vivo, suggesting that significant amounts of GFs were produced by the local cells within the wound. In addition, the half-life times of GFs locally produced in the wound, including PDGF-AA, PDGF-AB/BB, and VEGF, were significantly extended (p < 0.05). This work demonstrates that L-PRF can sustain the release of GFs and cytokines for up to 7 days, and it shows that the former can activate cells to produce additional mediators and amplify the communication network for optimizing the wound environment, thereby enhancing healing.

Increased local concentrations of growth factors from leucocyte- and platelet-rich fibrin do not translate into improved alveolar ridge preservation: An intra-individual mechanistic randomized controlled trial.

AIM: Leucocyte- and platelet-rich fibrin (L-PRF) has been tested for enhancing alveolar ridge preservation (ARP), but little is known about the local release profile of growth factors (GF), and the clinical equipoise related to its efficacy remains. This study compared the patterns of GF release, early soft tissue healing, and alveolar ridge resorption following unassisted healing and L-PRF application in non-molar extraction sockets. MATERIALS AND METHODS: Atraumatic tooth extraction of two hopeless teeth per patient was followed by unassisted healing or L-PRF placement to fill the socket in 18 systemically healthy, non-smoking subjects. This intra-individual trial was powered to assess changes in horizontal alveolar ridge dimensions 1 mm below the crest of alveolar bone. GF concentrations in wound fluid were assessed with a multiplex assay at 6, 24, 72, and 168 h. Early healing was evaluated with the wound healing index and changes in soft tissue volumes on serial digital scans. Hard tissue changes were measured on superimposed CBCT images after 5 months of healing. RESULTS: L-PRF resulted in higher GF concentrations in wound fluid (WF) than in the control, but no differences in release patterns or time of peak were observed. No inter-group differences in early healing parameters were observed. Alveolar bone resorption was observed in both groups. No significant inter-group differences were observed in hard tissue healing 1, 3, or 5 mm apical to the original bone crest or in the ability to digitally plan a prosthetically guided implant with or without bone augmentation. CONCLUSIONS: L-PRF increased the GF concentrations in WF of extraction sockets without shifting the pattern observed in unassisted healing, while the increased delivery did not translate into clinical benefits in early wound healing or ARP. The current findings question the assumption that increased local concentrations of GF by L-PRF translate into improved clinical outcomes. Additional definitive studies are needed to establish the benefits of L-PRF in ARP (ClinicalTrials.gov NCT03985033).

Assessment of masticatory function in the differential diagnosis of Stage IV periodontitis: A pilot diagnostic accuracy study.

BACKGROUND: After diagnosis of periodontitis is made, detection of Stage IV cases is critical for appropriate management that may call for interdisciplinary care. This study aims to identify and assess the accuracy of a simple screening approach for practice and surveillance of Stage IV periodontitis. METHODS: Masticatory function assessments by both validated self-reported masticatory dysfunction questionnaire and dual-color chewing gum mixing ability test (index test) were conducted in 214 consecutive patients, followed by a full-mouth periodontal examination. Periodontal diagnosis was based on the 2017 World Workshop classification of periodontal diseases (reference standard). Multivariate logistic regression and area under the receiver operating characteristic curve (AUROC) analyses were performed. RESULTS: Overall, the individual patient-reported masticatory dysfunction questions showed low to moderate accuracy for predicting Stage IV periodontitis. The objective measures of masticatory function by calculating the variance of hue from the chewing gum test performed better with an AUROC of 0.840. A diagnostic approach based on age, self-report of altered food type intake, and chewing gum test results exhibited excellent performance for predicting Stage IV periodontitis (sensitivity: 89.7%; specificity:76.3%; AUROC:0.912). CONCLUSIONS: Once the presence of periodontitis has been established, a simple diagnostic approach that does not require specialized workforce, complex, or lengthy assessment allows identification of patients with Stage IV periodontitis. This is important as these patients require specific case work up and interdisciplinary care pathways. Additional studies are required to validate the findings in multiple populations.

Food intake, masticatory function, tooth mobility, loss of posterior support, and diminished quality of life are associated with more advanced periodontitis stage diagnosis.

AIM: To describe periodontal and functional characteristics of subjects diagnosed with different stages of periodontitis and to associate measures of masticatory function and quality of life with periodontitis stage. MATERIALS AND METHODS: This was a cross-sectional study on a convenience sample of 214 subjects with periodontitis seeking oral care in a hospital setting. They received a full-mouth intra-oral examination including dental and periodontal charting by a single calibrated examiner who also established the periodontitis stage diagnosis. Subjects were assessed using the OHIP-14, a validated masticatory dysfunction questionnaire, and a quantitative test based on the ability to mix a dual colour chewing gum. Mixing was quantified based on the variance of hue (VOH) with a colorimetric software. Descriptive, univariate, and multivariate analyses were performed. RESULTS: Subjects with stage IV periodontitis reported greater impairment of oral-health-related quality of life, reduced food intake or altered food type intake attributed to difficulties in chewing, objective measures of masticatory dysfunction, tooth loss, as well as more advanced periodontal breakdown compared with subjects with stages I-III of the disease. Quantitative assessment of masticatory function was associated, in a multivariate analysis, with (i) loss of functional tooth units in the premolar/molar region, presence of hypermobile teeth, and severity of periodontal attachment loss, and (ii) age, body mass index, and periodontitis stage IV and grade C diagnosis. CONCLUSIONS: Subjects with stage IV periodontitis are characterized by a specific set of signs and symptoms of advanced periodontal breakdown and functional impairment, which impact on the quality of life and masticatory function/food intake choices. Stage IV periodontitis captures a clinical entity with distinct features and treatment needs. This study is registered in ClinicalTrials.gov (NCT03928080).