Tissue Engineering: Use of Growth Factors in Bone Regeneration

Tissue healing is a complex process involving a cascade of cellular and molecular events that are mostly shared by the different tissues of the body. Interestingly, the tissue repair process initiates immediately after a traumatic injury and is mediated and controlled by a wide range of cytokines, proteins, and growth factors released from platelets upon activation. Consequently, many growth factors have been considered as therapeutic molecules for the repair or regeneration of a wide range of tissues. Although their role has been only partially elucidated, the potential benefit of most growth factors has been demonstrated. In the last few years, the development of platelet-rich preparations has revolutionized the field of regenerative medicine, due to the repair capacities of the platelet-released growth factors that stimulate and accelerate both soft and hard tissue healing and regeneration. Today, autologous platelet concentrates (APCs) are used in a wide range of disciplines such as dentistry, oral surgery, orthopedics, sport medicine, dermatology, and plastic and reconstructive surgery. The purpose of this chapter is to describe the current evidence regarding the benefits of using autologous platelet concentrates in various oral surgery procedures, using a systematic review approach

A technique for the treatment of maxillary sinus membrane perforations occurred during endodontic surgery: a prospective comparative evaluation

Abstract Objectives The aim of this study was to evaluate the use of PRGF in endodontic surgery to treat sinus membrane perforation. Materials and methods A total of 20 patients (ten per group) were included. In the control group the lesion of the sinusal membrane was treated with collagen sponge. In the test group PRGF was used to close the communication with the sinus cavity. Results and conclusions The use of PRGF resulted in better postoperative quality of life parameters if compared to the negative control group. Perceived pain was significantly lower in the test group than in the control one for the first six days after intervention

Orthodontic Loads in Teeth after Regenerative Endodontics : A Finite Element Analysis of the Biomechanical Performance of the Periodontal Ligament

Altres ajuts: CERCA Programme/Generalitat de CatalunyaThe objective of this study was to analyse the stress distribution in the periodontal ligament and tooth structure of a cementum-reinforced tooth, a dentine-reinforced tooth and an immature tooth during orthodontic loads using a finite element analysis. A finite element model of a maxillary incisor and its supporting tissues was developed. The root was segmented into two parts: a part that represented a root in an immature state and an apical part that represented the tissue formed after regenerative endodontics. The apical part was given the mechanical properties of dentine or cementum. The three models underwent simulation of mesial load, palatal inclination and rotation. The mean stress values and stress distribution patterns of the periodontal ligament of the dentine- and cementum-reinforced teeth were similar in all scenarios. The maturation of the root, with either dentine or cementum, was beneficial for all scenarios, since the periodontal ligament of the immature tooth showed the highest mean stress values. Under the condition of this computational study, orthodontic loads can be applied in teeth previously treated with regenerative endodontics, since the distribution of stress is similar to those of physiologically mature teeth. In vivo studies should be performed to validate these results

Osteotome-Mediated Sinus Lift without Grafting Material: A Review of Literature and a Technique Proposal

Implant rehabilitation of the edentulous posterior maxilla may be a challenging procedure in the presence of insufficient bone volume for implant placement. Maxillary sinus augmentation with or without using grafting materials aims to provide adequate bone volume. The aim of the present study was to systematically review the existing literature on transalveolar maxillary sinus augmentation without grafting materials and to propose and describe an osteotome-mediated approach in postextraction sites in combination with platelet derivative. The systematic review showed that high implant survival rate (more than 96% after 5 years) can be achieved even without grafting the site, with a low rate of complications. Available alveolar bone height before surgery was not correlated to survival rate. In the described case report, three implants were placed in posterior maxilla after extraction of two teeth. An osteotome-mediated sinus lifting technique was performed with the use of platelet derivative (PRGF); a synthetic bone substitute was used to fill the gaps between implant and socket walls. No complications occurred, and implants were successfully in site after 1 year from prosthetic loading. The presented technique might represent a viable alternative for the treatment of edentulous posterior maxilla with atrophy of the alveolar bone though it needs to be validated by studies with a large sample size

Concentrated Growth Factors vs. Leukocyte-and-Platelet-Rich Fibrin for Enhancing Postextraction Socket Healing. A Longitudinal Comparative Study

Platelet concentrates (PCs) have been used for over 20 years in dentistry, as an adjunct to oral surgery procedures, to improve hard and soft tissue healing and control postoperative symptoms. Among various PCs, Leukocyte and Platelet-Rich Fibrin (L-PRF) has become very popular due to its excellent cost-effectiveness ratio, and to the simple preparation protocol, but comparative clinical studies with other PCs are lacking. The aim of this split-mouth cohort study was to evaluate the effect of Concentrated Growth Factors (CGF), a recently introduced PC, as compared to L-PRF for enhancing post-extraction socket healing. Methods: Patients in need of bilateral tooth extractions were included. Each side was treated with either CGF or L-PRF. Pain, socket closure and healing index were the main outcomes. Results: Forty-five patients (24 women), aged 60.52 ± 11.75 years (range 37–87 years) were treated. No significant difference in outcomes was found, except for Pain at day 1 (p < 0.001) and socket closure in the vestibulo-palatal/lingual dimension at day 7 post-extraction (p = 0.04), both in favor of CGF. Conclusions: based on the present results, CGF proved to be as effective and safe as L-PRF, representing a valid alternative option for improving alveolar socket healing and reducing postoperative discomfort

Penetration of Sodium Hypochlorite Modified with Surfactants into Root Canal Dentin

Abstract The aim of this study was to evaluate the effect of concentration, exposure time and temperature of sodium hypochlorite (NaOCl) added with surfactants on its penetration into dentinal tubules. Sixty-five extracted human permanent maxillary anterior teeth with single canals were prepared by ProTaper SX hand-operated instruments. The teeth were then sectioned perpendicular to the long axis. The crowns and apical thirds of all the teeth were removed. The remaining roots were processed into 4-mm-long blocks and stained overnight in crystal violet. One hundred and thirty stained blocks were further split into halves and treated by nine different types of NaOCl-based solutions. Three solutions were added with surfactants (Hypoclean, H6, Chlor-Xtra) and the others were regular hypochlorites at increasing concentrations (1%, 2%, 4%, 5.25%, <6%, 6% NaOCl) from different brands. The dentin blocks were exposed to the solutions for 2, 5, and 20 min at 20 °C, 37 °C and 45 °C, respectively. The depth of NaOCl penetration was determined by bleaching of the stain and measured by light microscopy at 20 and 40. Statistical comparisons were made by using a generalized linear model with Bonferroni's post-hoc correction. The shortest penetration (81±6.6 μm) was obtained after incubation in 1% NaOCl for 2 min at 20 °C; the highest penetration (376.3±3.8 μm) was obtained with Chlor-Xtra for 20 min at 45 °C. Varying NaOCl concentration produced a minimal effect while temperature and exposure time had a significant direct relationship with NaOCl penetration into dentinal tubules, especially those with lowered surface tension. The exposure time and temperature of sodium hypochlorite as well as the addition of surfactants may influence the penetration depth of irrigants into dentinal tubules

Comparison of Antimicrobial Substantivity of Six Root Canal Irrigants against Enterococcus faecalis

Introduction: The antimicrobial substantivity of Mixture of Doxycycline, Citric acid, and Tween 80 (MTAD), Tetraclean, Tetraclean NA, Q-Mix, 2% Chlorhexidine (CHX) and Octenisept was assessed in human root dentine blocks infected with Enterococcus (E.) faecalis. Methods and Materials: A total of 170 dentine tubes were prepared from human maxillary incisors. After crown and apical third removal, cementum was abraded. The remaining center-holed pieces were cut into 4-mm blocks, infected with E. faecalis in Brain Heart Infusion (BHI) broth for 28 days, then randomly divided into 6 experimental groups (n=25) and 2 controls (n=10). At 0, 7, 14, 21 and 28 days, dentine chips were removed from the canals, with sequential round burs with increasing diameters, and collected into freshly prepared BHI broth. After culturing, growing colonies were counted as colony forming units (CFU). Conventional non-parametric tests (Kruskal-Wallis and Mann-Whitney tests) were used to assess intra-group (at different time frames) and inter-group (at each experimental time) differences (P=0.05). Results: Tetraclean yielded the lowest CFU counts (P&lt;0.001) at each observation time. Tetraclean NA and Q-Mix showed better (P&lt;0.001) substantivity than 2% CHX and MTAD (except for Q-Mix versus MTAD at 14 days, P=0.21). Conclusions: In this in vitro study, Tetraclean NA and Q-Mix displayed the best antimicrobial substantivity against E. faecalis after Tetraclean in infected human root dentine. Considering the findings of our study and potential drawbacks of antibiotic-based irrigants, free-antibiotic irrigants may represent viable alternative for final rinse in root canal treatment.Keywords: Antimicrobial Substantivity; Enterococcus faecalis; MTAD; Qmix; Tetraclea

Short-term data suggests cognitive benefits in the elderly with single-implant overdentures.

DESIGN This study was an extension of a randomized crossover clinical trial approved by the institutional ethics committee (approval number: D2014-148) and adhered to the CONSORT guidelines. The original study juxtaposed patient contentment with single-implant overdentures (1-IODs) against conventional complete dentures (CCDs), with patient satisfaction being the primary focus. In this follow-up study, the cognitive function of edentulous patients receiving 1-IODs was assessed, specifically monitoring for the emergence of mild cognitive impairment (MCI) throughout a three-year period. Patient outcomes were systematically recorded at predetermined intervals: initially, two months post-1-IOD placement, after one year (with groups alternated between denture types at eight-month marks), then after two and three years. A prosthodontist with a decade of expertise performed all denture-related procedures. This follow-up emphasized the cognitive outcomes using the Montreal Cognitive Assessment (MoCA-J), considering it alongside previously documented results on masticatory function, bone resorption, survival rates, and patient-reported outcomes. CASE SELECTION Between 2015 and 2016, a follow-up study enrolled edentulous patients over 50 years of age who were proficient in Japanese, had sufficient mandibular bone for implants, and were free of systemic health issues and habits that could impact oral health. The participants were randomly divided into two groups after receiving a central mandibular implant. Group 1 initially used 1-IODs, and Group 2 used unloaded CCDs. After two months and subsequent periods, they swapped denture types. Eventually, all patients chose 1-IODs for continued use. Implant success was monitored over three years. The design featured block randomization and accounted for a sample size of 22, determined to be sufficient for evaluating the primary outcome of patient satisfaction. All patients underwent careful allocation and received customized dental interventions, with detailed radiographic planning and surgical precision guiding the implantation process. DATA ANALYSIS Multivariable linear mixed models were used to assess within-group changes in both overall and specific cognitive function scores across five timepoints. Age, assessment interval, and upper jaw denture status were incorporated as consistent variables, while individual participants were considered variable elements in the analysis. SPSS software version 22.0 was utilized to conduct the statistical tests, and a p value threshold of 0.05 was predetermined to establish statistical significance. RESULTS Twenty-two patients with edentulous mandibles received 1-IODs. Memory and executive functions saw significant score increases at multiple timepoints over the three-year period, with statistical significance. Though one participant dropped out and another passed away, and two did not complete the 3-year follow-up, the remaining 18 participants provided comprehensive data. Age and type of maxillary denture were significant factors, influencing MoCA-J scores with older participants and those with fixed dentures showing lower scores in certain domains. Overall, the findings illustrated the positive correlation between 1-IODs and cognitive function in older adults. CONCLUSIONS Older adults with no natural teeth left in their mandible showed improved cognitive function after one and three years of using 1-IODs, as reflected by their total and specific cognitive domain scores. The study suggests that such implant therapy may offer protective benefits against cognitive decline, demonstrating clinical relevance for patient care, regardless of the maxillary arch (antagonist) condition

Soft tissue augmentation applying a collagenated porcine dermal matrix during second stage surgery: A prospective multicenter case series

BACKGROUND The achievement and preservation of an adequate amount of soft tissue around implants is a critical factor for the prognosis of the treatment. PURPOSE To evaluate the effectiveness of a porcine dermal matrix applied during second stage implant surgery for horizontal soft tissue augmentation and preservation of dimensional stability. MATERIALS AND METHODS Twenty patients (mean age 50.2 ± 11.9 [SD] years) candidate to implant therapy and requiring soft tissue augmentation were recruited in four centers. Augmentation was performed in 24 cases. A porcine dermal matrix was placed into a buccal split-thickness pouch during uncovering surgery. Silicone impressions were taken before surgery (T0), 2 weeks later at suture removal (T2), 6 months (T3), and 24 months (T4) post augmentation. Dimensional changes of soft tissue were evaluated using superimposition of digitalized study casts. RESULTS Nineteen patients (23 implants) could be evaluated at 6 months and 13 patients (17 implants) at 24 months. After 6-month follow-up, there was a significant dimensional gain respect to baseline, averaging 0.83 ± 0.64 mm (P 0.5 mm in 65.2% and 64.7% of the cases, respectively. Soft tissue shrinkage averaged 34.2% ± 77.0% from T2 to T3 (P < .01) and did not change thereafter (P = .39). Shrinkage was more consistent in the posterior mandible than in the maxilla, but not significantly (P = .23 at 6-month and .36 at 24-month). No adverse events occurred. CONCLUSION Within the limitations of this prospective case series, the use of a porcine dermal matrix may provide consistent soft tissue augmentation that maintains up to 24-month follow-up, although graft shrinkage may occur in the first 6 months, depending on the location of surgery