Do recombinant, purified or concentrated growth factors enhance the regenerative potential of particulate bone graft substitutes in maxillary sinus floor augmentation? A systematic review and meta-analysis.

BACKGROUND: The clinical use of bioactive substances, such as growth factors, have significantly increased, however, potential regenerative effects derived from the addition of different growth factors to bone substitutes on maxillary sinus floor augmentation (MSA) procedures is still controversial. This systematic review (SR) aimed at answering the following question: "Do recombinant, purified and concentrated growth factors enhance the regenerative potential of particulate bone graft substitutes in maxillary sinus floor augmentation?". METHODS: Human studies comparing histomorphometric data of the outcomes of interest new bone formation, residual graft material, and fibrous tissue ratio following MSA procedures employing particulate bone grafts/substitutes in combination or not with growth factors were retrieved from PubMed/MEDLINE, Web of Science, Cochrane and Scopus online databases and complemented with a hand search. Controlled studies published in English up to December 2022 and reporting on histomorphometric data expressed as percent volume of the outcomes of interest were considered. Risk of bias was assessed, and a meta-analysis (MA) was performed to investigate the effects of supplementary growth factors on new bone formation, remaining graft particles and fibrous tissue ratio. RESULTS: Data of 613 samples from 477 patients reported in 22 publications were included. MA showed PRP or PRF resulted in 49% more new bone formation than in areas in control groups (P=0.004), and those areas supplemented with growth factors presented 57% less residual graft particles after healing (P<0.0001). A significant (P=0.03) 1.85-fold increase in connective tissue formation was noted in areas treated with rhBMP after healing. CONCLUSION: The MA provided evidence that selective supplementary growth factors may enhance new bone formation and accelerate particulate graft turnover, while rhBMP may significantly increase connective tissue formation in MSA procedures in humans.

Evaluation of Alveolar Bone Dimensions and Root Positioning of Anterior Teeth in the Maxilla.

Buccal bone walls present significant resorption after tooth extraction, possibly related to the smaller bone thickness, length, and the sagittal position of the root, as well as the bone morphology. The goal of the present study was to measure the thickness of the cortical bone of the vestibular and palatal walls in the anterior maxilla by means of CBCT images. Measurements were taken from CBCT scans of 300 maxillary anterior teeth from 50 patients (25 women, 25 men) aged 18 to 30 years. The parameters evaluated included the thickness of the buccal and palatal cortical bone in the cervical, apical, and middle thirds of the root, as well as six specific angular measurements from each tooth. The lateral incisors showed a significant difference in thickness between each of the buccal and palatal thirds, and measurements were also significantly smaller than the central and canine incisors. Bone anatomy is tooth-and location-specific, and thus the sagittal root position within the alveolus influences the regional bone morphology and may explain the gingival zenith position in the anterior maxilla. These specific buccal and palatal anatomic parameters should be carefully taken into consideration for surgical planning and intervention in the esthetic area.

Microspheres of alginate encapsulated minocycline-loaded nanocrystalline carbonated hydroxyapatite: therapeutic potential and effects on bone regeneration.

Background and objective: Tetracycline and its derivatives, combined with calcium phosphates, have been proposed as a delivery system to control inflammatory processes and chronic infections. The objective of this study was to evaluate the microspheres of alginate encapsulated minocycline-loaded nanocrystalline carbonated hydroxyapatite (CHAMINO) as a biomimetic device to carry out target-controlled drug delivery for alveolar bone repair. Methods: CHAMINO microspheres were implanted in a rat central incisor socket after 7 and 42 days. New bone was formed in both groups between 7 and 42 days of implantation. However, the bone growth was significantly higher for the CHAMINO microspheres. Results: The minocycline (MINO) loading capacity of the nanocrystaline carbonated hydroxyapatite (CHA) nanoparticles was 25.1±2.2 µg MINO/mg CHA for adsorption over 24 hrs. The alginate microspheres containing minocycline-loaded CHA were biologically active and inhibited the Enterococcus faecalis culture growth for up to seven days of the MINO release. An osteoblastic cell viability assay based on the resazurin reduction was conducted after the cells were exposed to the CHAMINO powder and CHAMINO microspheres. Thus, it was found that the alginate extracts encapsulated the minocycline-loaded CHA microspheres and did not affect the osteoblastic cell viability, while the minocycline-doped CHA powder reduced the cell viability by 90%. Conclusion: This study concluded that the alginate microspheres encapsulating the minocycline-loaded nanocrystalline carbonated hydroxyapatite exhibited combined antibacterial activity against Enterococcus faecalis with cytocompatibility and osteoconduction properties. The significant improvement in the new bone formation after 42 days of implantation suggests that the CHAMINO microsphere has potential in clinical applications of bone regeneration.

Single-stage advanced versus rotated flaps in the treatment of gingival recessions: A 5-year longitudinal randomized clinical trial.

BACKGROUND: The objective of the present study was to compare the efficacy of single-stage laterally positioned flap (LPF) and coronally advanced flap (CAF) techniques in the treatment of localized maxillary gingival recession (GR) defects, 1 and 5 years after surgical procedures. METHODS: Thirty-six patients with Miller Class I GR defects were randomly assigned to be treated by either CAF (n = 18) or LPF (n = 18). Recession height (RECH), width of keratinized tissue (WKT), probing depth (PD), vertical clinical attachment level (VAL), visual plaque score (VPS), and bleeding on probing (BOP) were assessed and compared. Clinical recordings were performed at baseline, 1 and 5 years later. The differences between initial clinical recordings and after 1 and 5 years were subjected to statistical analysis. RESULTS: Both flap designs effectively improved RECH and VAL on GR defects. The LPF resulted in significantly more gains in KTW and root coverage (RC) after 5 years. CONCLUSION: LPF and CAF procedures may be used for the treatment of GR, however, LPF results in greater longitudinal stability of RC and increased WKT in the treated areas.

Effects of methods of hydration of a biphasic ceramic graft on bone regeneration of extraction socket defects.

BACKGROUND: Alveolar volumetric changes are inherent to the healing process after tooth extraction and filling of the extraction site with biomaterials can reduce these volumetric changes and provide a more favorable environment for the future prosthetic restoration with implants. Among the biomaterials available, biphasic ceramic compounds have shown promissing clinical results, however, histologic evaluation of bone tissue response to different hydration and incorporation methods are limited. The objective of this study was to comparatively evaluate in vivo the osteoconductive potential of the biphasic ceramic bone substitute (SBC) composed of beta-tricalcium phosphate and hydroxyapatite after different hydration methodologies in rat extraction sockets. METHODS: Wistar rats (n = 20) were randomly distributed in two subgroups (G1, G2) according to the hydration methods used. After extraction of the right upper central incisor the alveoli were filled with SBC hydrated by two different methods. Group 1: biomaterial hydrated in blood; Group 2: biomaterial hydrated in physiologic saline. The animals were euthanized after 1 and 6 weeks for removal of the bone blocks containing the biomaterial and were submitted to histologic processing. Five-µm-thick demineralized sections of the samples were stained with hematoxylin and eosin (HE) and subjected to histomorphometric analysis. RESULTS: Bone formation was limited 7 days after the extraction procedure and increased in both groups between 7 and 42 days from surgery, demonstrating a time dependent increase of bone volume throughtout the experimental period (p < 0.05). CONCLUSIONS: The hydration of SBC with saline significantly increased new bone formation and reduced connective tissue volume after 42 days demonstrating that hydration method may significantly influence bone healing in such defects, and, thus should be carefully performed.

The relationship between open versus normal contact point and inter-proximal papilla dimensions in periodontally healthy young adults: A controlled clinical trial.

AIM: The gingival architecture is determined by the spatial orientation of the gingival zenith (GZ) and the inter-dental papillae (IP). Among the factors commonly associated with the presence and morphology of the IP, the contact point (CP) and the inter-dental distance relationships have been considered the most important. The objective of the present controlled clinical trial was to evaluate the role of the CP in determining the clinical and morphometric parameters of the inter-dental papilla. MATERIALS AND METHODS: The inter-dental papillae of sixty patients with unilateral diastemas were evaluated by means of periodontal probing, transgingival probing, the papilla presence index and morphometric measurement with a digital calliper and were analysed with a paired t-test, with significance set at alpha value of 0.05 or lower. RESULTS: All the papillae exhibited PPI score = 1. Papillary measurements were significantly increased in the experimental (diastema) group. CONCLUSIONS: In patients with gingival health, the dimensions of the IP are significantly increased in teeth without a contact point in comparison with their contra-lateral controls with a contact point. The contact point does not determine the presence and size of the inter-dental papilla, in patients with a healthy gingiva and without periodontal attachment loss.

Human intrabony defect regeneration with rhFGF-2 and hyaluronic acid - a randomized controlled clinical trial.

AIM: The goal of this study was to evaluate if a biological hydrogel of recombinant human Fibroblast Growth Factor type 2 (rhFGF-2) in a hyaluronic acid (HA) carrier applied in periodontal intrabony defects would enhance the clinical parameters of regeneration of the periodontal attachment apparatus MATERIALS AND METHODS: Thirty adult patients were evaluated. Two intrabony defects present in contra-lateral quadrants in each patient were randomly allocated for each of the treatment methods employed. Control group (n = 30) were treated by open debridement with the papilla preservation flaps, while the test group (n = 30) also received a topical application of rhFGF-2/HA in the intrabony defect. The parameters evaluated, at baseline and after one year, were, were probing depth (PD), gingival recession (REC), probing attachment level (PAL) and probing bone level (PBL). The primary outcome measures was PAL gain RESULTS: Test sites exhibited significantly more PD reduction (5.5 versus 2.9 mm), PAL gains (4.8 versus 2.2 mm) and shallower residual PD (4.2 versus 6.6 mm) than controls. Moreover, residual PD smaller than 5 mm (100 versus 0%) and PAL gain > 4 mm (60 versus 20%) was significantly more frequent in the test group CONCLUSION: Application of rhFGF-2/HA significantly improved clinical parameters of periodontal wound healing one year after treatment.

Effect of targeted delivery of bone morphogenetic protein-2 on bone formation in type 1 diabetes.

PURPOSE: Bone formation and healing are diminished in experimental type 1 diabetes. The present study investigated whether controlled local release of recombinant human bone morphogenetic protein 2 (rhBMP-2) stimulates bone defect healing in diabetes as a consequence of its anabolic effects on bone. MATERIALS AND METHODS: Bilateral experimental circular bone defects were created in the temporal bones of 64 BALB/cByJ mice. Defects were treated with acellular collagen sponge plus 0.4 or 1.8 µg of rhBMP-2 per defect, and untreated defects served as controls. The healing of the defects over a 14-day period in diabetic and nondiabetic mice was analyzed histomorphometrically. RESULTS: Diabetes inhibited bone formation in both untreated and BMP-treated bone defects. Controlled local release of rhBMP-2 significantly stimulated bone formation in diabetic animals, bringing it nearly to normal levels, and enhanced bone regeneration in normal animals. CONCLUSION: Recombinant human BMP-2 may be beneficial in treating deficient intramembranous bone formation in diabetes.

Superficial topography and porosity of an absorbable barrier membrane impacts soft tissue response in guided bone regeneration.

BACKGROUND: Surface topography and porosity of barrier membranes is suggested to impact the soft and hard tissue response. In this study, the specific soft and hard tissue response characteristics of a synthetic polylactide membrane are evaluated including soft tissue inflammation, osteogenesis, and osteopromotion. METHODS: Analysis of porosity and surface topography of the test material was performed by scanning electron microscopy. Transosseous parietal defects were surgically created bilaterally in 32 BalbC/ByJ mice and treated either with the barrier (test) or sham-operated (control). Healing was assessed histologically and histomorphometrically with quantification of bone bridging. RESULTS: Scanning electron microscopy analyses of the barrier revealed a microstructure resembling cancellous bone. Interconnecting pores and channels, measuring between 6 and 60 microm in diameter, formed by smooth internal walls were observed throughout the device. Two distinct patterns of porosity were observed. The external surface of the membrane was characterized by a highly porous structure, with minimal interporous nodes and average pore sizes ranging between 6 and 20 microm in diameter. The internal surface was characterized by a minimal porous structure, with significant interporous nodes and average pore sizes ranging between 18 and 60 mum in diameter. Histomorphometric analyses demonstrated increased bone bridging by 60% and 300% in membrane-treated sites after 14 and 28 days of healing, respectively. The rough surface of the barrier contained significantly more giant cells, whereas the smooth surface contained significantly more inflammatory cells. CONCLUSION: The surface topographies engineered on different sides of the barrier promote differential soft tissue responses leading, however, to similar amounts of enhanced bone formation.

Three-dimensional stress distribution in the human periodontal ligament in masticatory, parafunctional, and trauma loads: finite element analysis.

BACKGROUND: The presence of the periodontal ligament (PDL) makes it possible to absorb and distribute loads produced during masticatory function and other tooth contacts into the alveolar process via the alveolar bone proper. However, several factors affect the integrity of periodontal structures causing the destruction of the connective matrix and cells, the loss of fibrous attachment, and the resorption of alveolar bone. METHODS: The purpose of this study was to evaluate the stress distribution by finite element analysis in a PDL in three-dimensional models of the upper central incisor under three different load conditions: 100 N occlusal loading at 45 degrees (model 1: masticatory load); 500 N at the incisal edge at 45 degrees (model 2: parafunctional habit); and 800 N at the buccal surface at 90 degrees (model 3: trauma case). The models were built from computed tomography scans. RESULTS: The stress distribution was quite different among the models. The most significant values (harmful) of tensile and compressive stresses were observed in models 2 and 3, with similarly distinct patterns of stress distributions along the PDL. Tensile stresses were observed along the internal and external aspects of the PDL, mostly at the cervical and middle thirds. CONCLUSIONS: The stress generation in these models may affect the integrity of periodontal structures. A better understanding of the biomechanical behavior of the PDL under physiologic and traumatic loading conditions might enhance the understanding of the biologic reaction of the PDL in health and disease.