Guided Tissue Regeneration In Treatment Research Articles

Comparison of immediate vs. delayed guided tissue regeneration in Infrabony defect of second molars after adjacent third molar extraction: a retrospective study

BackgroundThe distal aspect of the second molar (d-M2) often exhibits infrabony defects due to the adjacent third molar. Although the defects can be treated by guided tissue regeneration (GTR) after removing the third molar, the optimal timing remains uncertain following third molar removal in clinical decision-making. This study aimed to compare delayed and immediate GTR treatments to assist in clinical decision-making.MethodsD-M2 infrabony defects with a minimum 1-year follow-up were collected and divided into three groups: Immediate GTR group, which underwent third molar extraction and received GTR simultaneously; Delayed GTR group, which underwent delayed GTR at least 3 months after third molar extraction; and Control group, which underwent only scaling and root planing during third molar extraction. The clinical and radiographic parameters related to the infrabony defect before GTR and post-surgery were evaluated using the Kruskal-Wallis test or one-way ANOVA, followed by post-hoc Dunn’s test or the Bonferroni test for pairwise comparisons.ResultsA total of 109 d-M2 infrabony defects were assessed. No significant differences were found between the two GTR groups, although both of them showed significant reductions in infrabony defect depth: the immediate GTR group (2.77 ± 1.97 mm vs. 0.68 ± 1.03 mm, p < 0.001) and the delayed GTR group (2.98 ± 1.08 mm vs. 0.68 ± 1.03 mm, p < 0.001) compared to the control group.ConclusionGTR can effectively improve d-M2 infrabony defects when the third molar is removed, whether simultaneously or delayed. Patients may experience less discomfort with immediate GTR treatment as it requires only one surgery.

NexGen regen? Challenges and opportunities for growth factors and signaling agents in periodontal regeneration at intrabony defects

Regeneration of periodontal tissues that have been destroyed by inflammatory periodontitis involves the initiation of tissue engineering and wound healing of multiple tissues involved in the function of the teeth, including the periodontal ligament, cementum, and alveolar bone. Such regeneration is termed guided tissue regeneration and the unique challenges to reconstruct these tissues involves a complex interplay of cells, signaling molecules, and scaffolds. While traditional guided tissue regeneration treatments have involved cell occlusive membranes, bone replacement graft scaffolds, and endogenous multipotent mesenchymal stem cells, the use of adjunctive materials to enhance healing outcomes has been studied and many such adjunctive factors are in common current clinical use. This report will focus on the current and emerging adjunctive growth factors and signaling molecules that can be used to optimize periodontal regeneration in periodontal intrabony defects, their mechanisms of action, the challenges associated with periodontal regeneration, and future avenues for research.

3D-Printed Soft Membrane for Periodontal Guided Tissue Regeneration.

The current study aimed to perform an in vivo examination using a critical-size periodontal canine model to investigate the capability of a 3D-printed soft membrane for guided tissue regeneration (GTR). This membrane is made of a specific composition of gelatin, elastin, and sodium hyaluronate that was fine-tuned and fully characterized in vitro in our previous study. The value of this composition is its potential to be employed as a suitable replacement for collagen, which is the main component of conventional GTR membranes, to overcome the cost issue with collagen. Critical-size dehiscence defects were surgically created on the buccal surface of the roots of canine bilateral mandibular teeth. GTR treatment was performed with the 3D-printed membrane and two commercially available collagen membranes (Botiss Jason® and Smartbrane-Regedent membranes) and a group without any membrane placement was considered as the control group. The defects were submerged with tension-free closure of the gingival flaps. Histologic and histometric analyses were employed to assess the periodontal healing over an 8-week experimental period. Histometric evaluations confirmed higher levels of new bone formation in the 3D-printed membrane group. Moreover, in all defects treated with the membranes, the formation of periodontal tissues, bone, periodontal ligaments, and cementum was observed after 8 weeks, while in the control group, only connective tissue was found in the defect sites. There was no clinical sign of inflammation or recession of gingiva in any of the groups. The 3D-printed gelatin/elastin/sodium hyaluronate membrane can be safe and effective for use in GTR for periodontal tissue regeneration therapies, with better or comparable results to the commercial collagen membranes.

Outcome of Combined Periodontal-Orthodontic Treatment of Pathologic Tooth Migration: A Longitudinal Study

Introduction: A number of periodontal bone abnormalities, most of which are horizontal, have been associated with flared and long incisors. Individuals with anterior incisor displacement and periodontal disease may benefit from orthodontic-periodontal therapy. Objective: To determine the outcome of combined periodontal-orthodontic treatment of pathologic tooth migration Study design: A longitudinal study Place and Duration: This study was conducted at Rehman college of dentistry Peshawar, Pakistan from February 2022 to July 2022 Methodology: A 4-person team designed the study's procedures. On 56 maxillary incisors with horizontal bone anomalies, this surgery was performed to remove circumferential supracrestal fibrotomy and orthodontic-periodontal therapy. To compensate for the angular bone shortage in front teeth treated with orthodontics, guided tissue regeneration and periodontal regenerative surgery were performed. Before, throughout, and six months after guided tissue regeneration treatment (T1), cone-beam computed tomography images were done (T2). At each of the first three time points, the depth of the probing pocket and the degree of clinical attachment loss were determined. Paired t-tests were used to analyse the data. Results: Clinical attachment loss decreased by 0.28 mm from T0 to T1 (P &lt;0.05). The distance between the cementoenamel junction and the bone top decreased by 0.65 mm (P &lt;0.05). Alveolar bone thickness decreased by 0.45 mm on both the lingual and labial sides of the bone (P&lt;0.05). Bone anomalies in some teeth have been converted from horizontal to vertical. From T1 to T2, radiographic testing revealed a 2.16 mm vertical and 1.45 mm horizontal bone redeposition (P&lt;0.05), as well as improvements in probing pocket depth and clinical attachment loss (P&lt;0.05). During combination therapy, the cementoenamel distance decreased from 2.10 mm to 1.31 mm (P &lt;0.05). Conclusion: We were able to address periodontal diseases caused by improper bone implantation by combining orthodontic and periodontal treatment. By altering the bone structure, it is possible to improve the outcome of directed tissue regeneration following orthodontic invasion with fibrotomy. Keywords: orthodontic and periodontal treatment, outcome, bone implantation, Periodontal disease

Low-intensity pulsed ultrasound promotes periodontal regeneration in a beagle model of furcation involvement.

Objective: To evaluate the regeneration potential of periodontitis tissue treated by low-intensity pulsed ultrasound (LIPUS) combined with the guided tissue regeneration (GTR) technique in a beagle model of furcation involvement (FI). Background: Achieving predictable regeneration remains a clinical challenge for periodontitis tissue due to the compromised regenerative potential caused by chronic inflammation stimulation. LIPUS, an FDA-approved therapy for long bone fracture and non-unions, has been demonstrated effective in the in vitro attenuation of inflammation-induced dysfunction of periodontal ligament stem cells (PDLSCs), the key cells contributing to periodontal regeneration. However, the in vivo effect of LIPUS on periodontitis tissue is rarely reported. Methods: A beagle model of FI was established, and the experimental teeth were randomly assigned into three groups: control group, GTR group, and GTR+LIPUS group. Radiographic examinations were performed, and clinical periodontal parameters were recorded to reflect the periodontal condition of different groups. Histological analyses using H&E and Masson’s staining were conducted to evaluate the periodontal tissue regeneration. Results: LIPUS could enhance new periodontal bone formation and bone matrix maturity in FI after GTR treatment. Moreover, clinical assessment and histomorphometric analyses revealed less inflammatory infiltration and superior vascularization within bone grafts in the LIPUS treatment group, indicating the anti-inflammatory and pro-angiogenic effects of LIPUS in FI. Conclusion: Our investigation on a large animal model demonstrated that LIPUS is a promising adjunctive approach for the regeneration of periodontitis tissue, paving a new avenue for LIPUS application in the field of periodontal regenerative medicine.

Guided Tissue Regeneration Treatment Yields Better Results in Class II Furcations in the Mandible Than in the Maxilla: A Retrospective Study.

Absorbable porcine collagen membrane with a bovine bone graft can be considered for regenerative treatment in periodontal class II furcation defects. We evaluated the clinical efficacy of guided tissue regeneration (GTR) treatment with bovine bone xenograft and a porcine collagen membrane in molars with class II furcations. Probing depth (PD), clinical attachment level (CAL), and bone level (BL) were recorded at baseline and at 3, 6, and 9 months postoperatively. Thirty class II furcation defects from the lower and upper molars were assessed. Significant improvements in PD and CAL were observed from baseline to 9 months in all groups (p < 0.01). BL improved in all groups except group A in the upper molars in radiographic assessment (p < 0.05). The lower and upper molars showed PD reduction of 50.5% ± 7.44% and 46.2% ± 11.2%, respectively, at 9 months (p = 0.044). In furcations of 1–3 mm, the lower and upper molars showed PD reductions of 51.2% ± 4.49% and 36.5% ± 16.14%, respectively (p = 0.035). The lower and upper molars showed a CAL gain of 51.1% ± 4.64% and 33.6% ± 18.8%, respectively (p = 0.037). Thus, GTR with bovine bone graft and porcine collagen membrane yielded good results in class II furcations, with better results in the lower than in the upper molars.

Bismuth subsalicylate incorporated in polycaprolactone-gelatin membranes by electrospinning to prevent bacterial colonization

Periodontitis is a chronic, multifactorial, inflammatory disease characterized by the progressive destruction of the periodontal tissues. Guided tissue regeneration (GTR), involving the use of barrier membranes, is one of the most successful clinical procedures for periodontal therapy. Nevertheless, rapid degradation of the membranes and membrane-related infections are considered two of the major reasons for GTR clinical failure. Recently, integration of non-antibiotic, antimicrobial materials to the membranes has emerged as a novel strategy to face the bacterial infection challenge, without increasing bacterial resistance. In this sense, bismuth subsalicylate (BSS) is a non-antibiotic, metal-based antimicrobial agent effective against different bacterial strains, that has been long safely used in medical treatments. Thus, the aim of the present work was to fabricate fibrillar, non-rapidly bioresorbable, antibacterial GTR membranes composed of polycaprolactone (PCL), gelatin (Gel), and BSS as the antibacterial agent. PCL-G-BSS membranes with three different BSS concentrations (2 wt./v%, 4 wt./v%, and 6 wt./v%) were developed by electrospinning and their morphology, composition, water wettability, mechanical properties, Bi release and degradation rate were characterized. The Cytotoxicity of the membranes was studied in vitro using human osteoblasts (hFOB) and gingival fibroblasts (HGF-1), and their antibacterial activity was tested against Aggregatibacter actinomycetemcomitans, Escherichia coli, Porphyromonas gingivalis and Staphylococcus aureus. The membranes obtained exhibited adequate mechanical properties for clinical application, and appropriate degradation rates for allowing periodontal defects regeneration. The hFOB and HGF-1 cells displayed adequate viability when in contact with the lixiviated products from the membranes, and, in general, displayed antibacterial activity against the four bacteria strains tested. Thus, the PCL-G-BSS membranes showed to be appropriate as potential barrier membranes for periodontal GTR treatments.

GTR Treatment in Furcation Grade II Periodontal Defects with the Recently Reintroduced Guidor PLA Matrix Barrier: A Case Series with Chronological Step-by-Step Illustrations

Molars with a furcation involvement (FI) exceeding grade 1 according to Hamp's classification are at approximately doubled risk of tooth loss. Guided tissue regeneration (GTR) is a regenerative approach in the treatment of periodontal defects and is aimed at achieving new clinical attachment formation. The aim of this case series was to assess the efficacy of a newly reintroduced polylactic acid (PLA) matrix barrier and to evaluate the feasibility of the surgical approach. 11 patients with an average age of 58.7 years were treated with GTR using a PLA matrix barrier. Patients were instructed not to brush and chew on the treated side for 4 weeks. A gentle clinical probing was performed after 6 months for the first time after surgery. The patients were included into individual maintenance program at three months' interval. The clinical improvement was expressed by reduced horizontal penetration of the probe accompanied by vast resolution of the vertical defect component. The change from grade II to grade I or complete resolution of the FI could be seen in 8 from 11 sites included. The newly reintroduced PLA matrix barrier showed promising results after a 12-month observation period with clinical attachment gain.

Effect of concentrated growth factors combined with guided tissue regeneration in treatment of classII furcation involvements of mandibular molars

Tissues loss due to periodontal disease is typically treated by a variety of regenerative treatment modalities, including bone grafts, guided tissue regeneration (GTR) and growth factors, to reform the supporting tissues of teeth. Concentrated growth factors (CGF) are produced by centrifuging blood samples at alternating and controlled speeds using a special centrifuge. The purpose of this study was to evaluate whether GTR could improve the effect of CGF combined with bone graft in the treatment of classII furcations of mandibular molars. In the present study, thirty-five classII furcation involvements were included and randomly divided into two groups. The experimental group (n=17) accepted GTR combined with CGF and bone graft therapy, and the controlled group (n=18) accepted CGF combined with bone graft therapy. The clinical examinations and cone beam computed tomography (CBCT) were performed at baseline and 1 year post-surgery. Comparisons of clinical and CBCT data before and after operation between the experimental group and the control group were made. The clinical and CBCT data of both groups were not statistically different at baseline (P>0.05). At the end of 1 year post-surgery, the clinical parameters of both groups were significantly improved (P<0.001). The probing depths of the experimental group were (4.81±1.95) mm and (3.56±1.94) mm, respectively, significantly higher than the changes of the control group (P<0.001). The vertical and horizontal attachment gains of the experimental group were (4.11±1.98) mm and (3.84±1.68) mm, respectively, significantly higher than the changes of the control group (P<0.001). At the end of 1 year post-surgery, the experimental group showed significantly higher bone gain at vertical and horizontal directions compared with those of the control group: (3.84±1.68) and (3.88±2.12) mm, respectively (P<0.001). Within the limitation of the present study, GTR showed positive role in the effect of CGF combined with bone graft in the treatment of classII furcation involvements of mandibular molars.

Antibacterial composite membranes of polycaprolactone/gelatin loaded with zinc oxide nanoparticles for guided tissue regeneration

The bacterial colonization of absorbable membranes used for guided tissue regeneration (GTR), as well as their rapid degradation that can cause their rupture, are considered the major reasons for clinical failure. To address this, composite membranes of polycaprolactone (PCL) and gelatin (Gel) loaded with zinc oxide nanoparticles (ZnO-NPs; 1, 3 and 6 wt% relative to PCL content) were fabricated by electrospinning. To fabricate homogeneous fibrillar membranes, acetic acid was used as a sole common solvent to enhance the miscibility of PCL and Gel in the electrospinning solutions. The effects of ZnO-NPs in the physico-chemical, mechanical and in vitro biological properties of composite membranes were studied. The composite membranes showed adequate mechanical properties to offer a satisfactory clinical manipulation and an excellent conformability to the defect site while their degradation rate seemed to be appropriate to allow successful regeneration of periodontal defects. The presence of ZnO-NPs in the composite membranes significantly decreased the planktonic and the biofilm growth of the Staphylococcus aureus over time. Finally, the viability of human osteoblasts and human gingival fibroblasts exposed to the composite membranes with 1 and 3 wt% of ZnO-NPs indicated that those membranes are not expected to negatively influence the ability of periodontal cells to repopulate the defect site during GTR treatments. The results here obtained suggest that composite membranes of PCL and Gel loaded with ZnO-NPs have the potential to be used as structurally stable GTR membranes with local antibacterial properties intended for enhancing clinical treatments.

Comparison of clinical effects of three kinds of bone graft in the treatment of periodontal intra-bony defects

Objective To compare the clinical effects of guided tissue regeneration (GTR) combined with different bone graft materials, including Bio-Gene, Bone3 and Bio-Oss, in the treatment of periodontal intra-bony defects. Methods Eighteen patients with chronic periodontitis with periodontal intra-bony defects were randomly divided into the Bio-Gene group, the Bone3 group and Bio-Oss group. After periodontal debridement, periodontal bone grafting combined with GTR surgery was performed in all patients. The clinical and radiographic parameters of patients were collected before surgery, suture removal (2 weeks after surgery), and 6 months after surgery, including periodontal exploration depth (PD), clinical attachment loss (CAL), gingival recession (GR), and residual alveolar bone height (RBH). Results The wounds healed well in all patients when the suture was removed. The stage I healing was obtained without infection or wound dehiscence, and the postoperative discomfort was acceptable. At 6 months after periodontal bone grafting combined with GTR treatment, the PD and CAL indexes in the three groups were significantly improved compared with those before surgery (all P 0.05). Imaging results showed that new bone formation was observed in the original bone defect area in all three groups after 6 months of the treatment, the bone density was similar to the surrounding bone tissue. Besides, the RBH% increased significantly compared with that before the treatment (all P 0.05). Conclusions Bio-Gene, Bone3 and Bio-Oss are all reliable bone graft materials for the treatment of alveolar bone defects caused by periodontitis, which can significantly improve the osteogenesis effect. Key words: Periodontitis; Intra-bony defects; Periodontal bone grafting; Guided tissue regeneration; Bone substitute

Amnion membrane as a novel barrier in the treatment of intrabony defects: a controlled clinical trial.

The purpose of this 6-month randomized, controlled, blinded, clinical trial was to evaluate and compare the efficacy of amnion membrane (AM) with deproteinized bovine bone mineral (BBM) and a collagen membrane (CM) with BBM in guided tissue regeneration (GTR) for the treatment of intrabony periodontal defects. Ten chronic periodontitis patients with bilateral intrabony defects with radiographic evidence of intrabony component ≥ 4 mm and probing pocket depths (PPDs) ≥ 6 mm were treated with AM+BBM, and the control group was managed with CM+BBM. Periodontal clinical parameters were recorded at baseline and at 6 months after treatment. PPD, clinical attachment level (CAL), and probing bone (PB) showed significant improvements after 6 months in both the test and control groups. Gingival recession showed a significant increase in the control group but not in the test group. The changes in mean PPD, PB, and CAL preoperatively and postoperatively between the groups were not significant. There was no significant relationship between the depth of the baseline bony defect and CAL gain. Both AM and CM in conjunction with BBM provided improvement of clinical periodontal parameters. AM did not induce significant gingival recession and is suggested as a new barrier membrane in GTR treatment.

The heat-compression technique for the conversion of platelet-rich fibrin preparation to a barrier membrane with a reduced rate of biodegradation.

Platelet-rich fibrin (PRF) was developed as an advanced form of platelet-rich plasma to eliminate xenofactors, such as bovine thrombin, and it is mainly used as a source of growth factor for tissue regeneration. Furthermore, although a minor application, PRF in a compressed membrane-like form has also been used as a substitute for commercially available barrier membranes in guided-tissue regeneration (GTR) treatment. However, the PRF membrane is resorbed within 2 weeks or less at implantation sites; therefore, it can barely maintain sufficient space for bone regeneration. In this study, we developed and optimized a heat-compression technique and tested the feasibility of the resulting PRF membrane. Freshly prepared human PRF was first compressed with dry gauze and subsequently with a hot iron. Biodegradability was microscopically examined in vitro by treatment with plasmin at 37°C or in vivo by subcutaneous implantation in nude mice. Compared with the control gauze-compressed PRF, the heat-compressed PRF appeared plasmin-resistant and remained stable for longer than 10 days in vitro. Additionally, in animal implantation studies, the heat-compressed PRF was observed at least for 3 weeks postimplantation in vivo whereas the control PRF was completely resorbed within 2 weeks. Therefore, these findings suggest that the heat-compression technique reduces the rate of biodegradation of the PRF membrane without sacrificing its biocompatibility and that the heat-compressed PRF membrane easily could be prepared at chair-side and applied as a barrier membrane in the GTR treatment.

An insight into the possibilities of fibroblast growth factor in periodontal regeneration

Periodontitis is caused by bacterial biofilms and is modulated by a variety of risk factors. The periodontal ligament comprises heterogeneous cell populations which are lost in the disease process. A variety of regenerative therapies, such as bone grafts, guided tissue regeneration treatment, application of enamel matrix derivative, have been introduced, with some success in periodontal tissue regeneration. Topical application of recombinant cytokines is now one of the most effective methods to stimulate stem cells. Researchers are now exploring the potential applications and uses of fibroblast growth factor in periodontal regeneration.

Amnion–Chorion Allograft Barrier Used for Guided Tissue Regeneration Treatment of Periodontal Intrabony Defects: A Retrospective Observational Report

Introduction: Combination guided tissue regeneration (GTR) for the treatment of periodontal intrabony defects has been an accepted treatment modality for nearly 30 years and has undergone a number of changes during this time, including the use of multiple different barrier membrane materials. Amnion–chorion membrane (ACM) is a placental‐derived tissue that has been used in medicine for &gt;100 years and recently introduced for combination GTR use in dentistry. This retrospective observational report documents use of ACM for combination GTR treatment of periodontal intrabony defects with a minimum of 12‐month post‐surgical observation.Case Series: Review of the practice's electronic database revealed that 114 patients were treated with GTR therapy from March 2010 to October 2011. Of these patients, 64 were treated with ACM combination GTR therapy and had ≥12 months of follow‐up. All patients were diagnosed with localized moderate‐to‐severe chronic periodontitis and exhibited radiographic evidence of ≥1 vertical osseous defect. All patients were treated by thorough degranulation of intrabony periodontal defects and placement of bone allograft covered by ACM. Clinical measurements 12 months after surgery revealed an average probing depth reduction of 5.06 ± 1.37 mm and clinical attachment level improvement of 4.61 ± 1.29 mm.Conclusion: The results of this retrospective observational report are promising and warrant additional controlled, long‐term studies to further evaluate the effectiveness of ACM for combination GTR treatment of periodontal intrabony defects.

Histological and histomorphometric analysis of animal experimental dehiscence defect treated with three bio absorbable GTR collagen membrane

Guided tissue regeneration (GTR) allows mesenchymal cells to repopulate the defects. However, there is limited information regarding the efficacy of different membranes. The present study was designed to histologically and histomorphometrically compare three collagen membranes in regenerative treatment of dehiscence defects in dogs. This 8 weeks experimental animal study comprised 4 healthy dogs. 5 × 5 mm periodontal dehiscences were created in each side of the mandible (4 dehiscences in each side of dogs' mandible). In each side, one dehiscence defect was left uncovered as a control site and three other sites were randomly covered with different collagen membranes (Biogide (BG), Biomend (BM), and Cytoplast (CYT)). Histomorphometric and histologic analysis were conducted at 4 and 8 weeks. Data were analyzed using ANOVA, Mann-Withney, Kruskal-Wallis and Fisher 's exact tests (α = 0.05). According to histomorphometric analysis there was a significant difference between treatment and control groups regarding the bone formation and the distance between the reference point and apical end of junctional epithelium (DJE) (P < 0.05). At 4 weeks, the maximum amount of bone thickness and height was observed in BG and CYT respectively, and this maximum rate was seen with the use of BG at 8 weeks. It was shown that DJE reached its highest rate in BM and CYT at 4 and 8 weeks, respectively. Organized PDL was formed in treatment groups. The membrane-treated groups had a statistically significant increase in bone formation and connective tissue attachment compared to control groups. However, there are some differences among experimental groups, which should be considered in GTR treatments.

Treatment of Intrabony Defects After Impacted Mandibular Third Molar Removal With Bioabsorbable and Non‐Resorbable Membranes

Mandibular second molar (M2) periodontal defects after third molar (M3) removal in high-risk patients are a clinical dilemma for clinicians. This study compares the healing of periodontal intrabony defects at distal surfaces of mandibular M2s using bioabsorbable and non-resorbable membranes. Eleven patients with bilateral probing depths (PDs) ≥6 mm distal to mandibular M2s and intrabony defects ≥3 mm, related to the total impaction of M3s, were treated with M3 extraction and covering of the surgical bone defect with a bioabsorbable collagen barrier on one side and a non-resorbable expanded polytetrafluoroethylene (ePTFE) barrier contralaterally. The PD, clinical attachment level (CAL), M2 mobility, and furcation class probing were evaluated preoperatively and 3, 6, and 9 months postoperatively. Intraoral periapical radiographs were taken immediately preoperatively and 3 and 9 months postoperatively. Both treatment modalities were successful. At 9 months, the mean PD reduction was 5.2 ± 3.9 mm for bioabsorbable sites and 5.5 ± 3.0 mm for non-resorbable sites; the CAL gain was 5.9 ± 3.3 mm and 5.5 ± 3.4 mm, respectively. The outcome difference between the two sites for PD and CAL did not differ statistically (P >0.05) at any assessment time. Bioabsorbable collagen membranes in guided tissue regeneration treatment of intrabony defects distal to the mandibular M2 obtained the same marked PD reductions and CAL gains as non-resorbable ePTFE membranes after M3 extraction.

Enzymatically Enhanced Guided Tissue Regeneration

In order to improve the efficacy of mem- branes used for guided tissue regeneration treatments, collagen membranes were surface-modified with the pro-mineralization enzyme alkaline phosphatase (ALP). ALP was surface-immobilized using electrostatic spray deposition (ESD) to preserves the biological activity of the enzyme. Initially, the optimal ALP-deposition time was assessed using ALP-activity assays and an immersion exper- iment with subsequent measurements on calcium deposi- tion. These initial experiments demonstrated that optimally efficient membranes were obtained with an ALP deposition time of 30 minutes. Subsequently, ALP-coated and non- coated controls were enrolled in a cell culture experiment with primary rat bone marrow derived osteoblast-like cells. ALP-coated membranes demonstrated to have no effect on cell proliferation and morphology, but significantly accel- erated the mineralization of the extracellular matrix. These results show the potential of ALP as a surface-immobilized active enzyme in biomaterial research and justify animal experimental work on this topic to obtain in vivo data.

Autogenous Periosteal Barrier Membranes and Bone Grafts in the Treatment of Periodontal Intrabony Defects of Single‐Rooted Teeth: A 12‐Month Reentry Randomized Controlled Clinical Trial

This randomized clinical trial compares the outcomes of combination treatment by autogenous periosteal membranes and bone graft versus guided tissue regeneration (GTR) with collagen membranes or open-flap debridement (OFD) only in the treatment of intraosseous defects. Forty-two patients affected by moderate to severe chronic periodontitis were enrolled. Each patient had one deep intrabony defect (≥6 mm). They were randomly assigned into three groups: patients treated with 1) an OFD procedure alone (OFD group); 2) a GTR procedure with collagen membranes (GTR group); and 3) a combined treatment procedure by autogenous periosteal membranes and autogenous bone chips (aCPRT group). Clinical and intrasurgical examinations including probing depth (PD), clinical attachment level (CAL), gingival recession (GR), and defect bone level (DBL) were performed at baseline and after 1 year. After 1 year, all of the evaluated clinical parameters showed statistically significant changes from baseline within each group (P <0.01). The GTR and aCPRT groups had significantly greater PD reductions (5.2 and 4.4 mm, respectively) and CAL (3.2 and 3.9 mm) and DBL gains (2.4 and 3.1 mm) compared to the OFD group (PD, 2.9 mm; CAL, 1.6 mm; DBL, 1.5 mm); moreover, the aCPRT group showed a significantly smaller GR increase (0.5 mm) and a greater DBL gain (3.1 mm) compared to the GTR group (2 and 2.4 mm, respectively; P <0.05). Both the GTR and aCPRT treatments produce additional clinical benefits over OFD alone. Moreover, the aCPRT technique can minimize post-surgical GR and produce better defect bone-level improvement.

Guided tissue regeneration combined with a deproteinized bovine bone mineral (Bio‐Oss®) in the treatment of intrabony periodontal defects: 6‐year results from a randomized‐controlled clinical trial

To present the 6-year results of a randomized-controlled clinical trial evaluating guided tissue regeneration (GTR) combined with or without deproteinized bovine bone mineral (DBBM) in intrabony defects. In each of 45 patients, one defect was treated with GTR combined with DBBM hydrated in saline (DBBM-) or gentamicin sulphate (DBBM+) or with GTR alone. Clinical parameters were recorded pre-surgery, at 1 and 6 years postsurgery. Thirty-six patients/33 teeth were available for the 6-year control. Statistically significant clinical improvements were observed for all treatments. Clinical attachment level (CAL) gain averaged 2.5 mm (DBBM-), 4.1 mm (DBBM+), and 3.0 mm (GTR) at 1 year postsurgery, and remained stable over 5 additional years (2.3, 4.1, and 2.7 mm, respectively). Treatment did not appear to influence residual probing depths (PDs) or CAL gains at 6 years postsurgery, or the extent of PD and CAL change from 1 to 6 years, and did not associate with sites losing CAL during follow-up. No association of grafting with sites showing CAL gain >or=4 mm at the 1- or 6-year control was observed. The improvements in periodontal conditions obtained after GTR treatment with or without the adjunct use of DBBM can be preserved on a long-term basis.