Regeneration of critical-sized grade II furcation using a novel injectable melatonin-loaded scaffold.

BACKGROUND: Periodontal regenerative therapy using bone-substituting materials has gained favorable clinical significance in enhancing osseous regeneration. These materials should be biocompatible, osteogenic, malleable, and biodegradable. This study assessed the periodontal regenerative capacity of a novel biodegradable bioactive hydrogel template of organic-inorganic composite loaded with melatonin. MATERIALS AND METHODS: A melatonin-loaded alginate-chitosan/beta-tricalcium phosphate composite hydrogel was successfully prepared and characterized. Thirty-six critical-sized bilateral class II furcation defects were created in six Mongrel dogs, and were randomly divided and allocated to three cohorts; sham, unloaded composite, and melatonin-loaded. Periodontal regenerative capacity was evaluated via histologic and histomorphometric analysis. RESULTS: Melatonin-treated group showed accelerated bone formation and advanced maturity, with a significant twofold increase in newly formed inter-radicular bone compared with the unloaded composite. The short-term regenerative efficacy was evident 4 weeks postoperatively as a significant increase in cementum length concurrent with reduction of entrapped epithelium. After 8 weeks, the scaffold produced a quality of newly synthesized bone similar to normal compact bone, with potent periodontal ligament attachment. CONCLUSIONS: Melatonin-loaded hydrogel template accelerated formation and enhanced quality of newly formed bone, allowing complete periodontal regeneration. Furthermore, the scaffold prevented overgrowth and entrapment of epithelial cells in furcation defects.

Effectiveness of Platelet-Rich Fibrin with Decalcified Freeze-Dried Bone Allograft Compared to Decalcified Freeze-Dried Bone Allograft Alone in Mandibular Grade-II Furcation Defects: A Quasi-Experimental Study

ABSTRACT Objective: To assess the effectiveness of platelet-rich fibrin (PRF) with decalcified freeze-dried bone allograft (DFDBA) compared to DFDBA alone in mandibular grade-II furcation defects. Material and Methods: A quasi-experimental study was conducted on nine patients with chronic periodontitis, each having two almost identical mandibular grade II furcation defects. Test sites (left mandibular first molars) were treated with open flap debridement (OFD), DFDBA, and PRF, whereas control sites (right mandibular first molars) received OFD and DFDBA alone. Clinical parameters (plaque index (PI), gingival index (GI), vertical clinical attachment level (VCAL) and horizontal clinical attachment level (HCAL) into the furcation defect) and radiographic measurements (mean alveolar bone defect) were done at baseline and after six months postoperatively. Results: The gain in relative horizontal clinical attachment level (RHCAL) in the test sites was 2.94±0.52 mm compared to 1.33±0.35 mm in control sites (p=0.01). Improvement in mean alveolar bone defect (MABD) (was 1.21±0.5 mm2 at test sites compared to 1.15±0.7 mm2 at control sites) probing pocket depth (PPD), recession, relative vertical attachment level (RVCAL), and percentage of bone fill was found in the test sites compared to control, which statistically insignificant. Conclusion: The test sites had better outcomes than control sites, which was significant for the parameter RHCAL. Therefore, combining the biological benefits of autologous PRF with DFDBA is an efficient and economical treatment modality for the management of mandibular grade II furcation defects.

Accuracy and Reliability of CBCT Compared to Clinical Probing in Detection of Trifurcation Defects: An In Vivo Study.

Background: Furcation defects are areas of pathological bone resorption in multirooted teeth. The aim of the study was to compare the measurements of trifurcation bone loss, measured using CBCT, versus clinical measurements in order to evaluate the efficacy of CBCT as an adjunctive diagnostic tool. Material and Methods. The included patients had both CBCT scans for maxillary molars and completed periodontal charts. Clinical examination consisted of probing and detection of vertical and horizontal furcation defects. These were measured and recorded. CBCT measurements were then evaluated using the linear measuring tool in Carestream imaging software (Carestream, Rochester, USA) and iCAT (Imaging Sciences, Hatfield, USA). These measurements of the CBCT images were then documented and compared to clinical findings. The two examiners were blinded to each other's measurements. Results: The most common tooth with a detected furcation defect was tooth #2 (31.7%), followed by tooth #15 (26.8%) and #3 (21.9%). The least common tooth with a detected furcation defect was #14 (19.5%). The mean values of buccal furcation for clinical and CBCT measurements were 3.01 mm and 2.6 mm, respectively. The measurements of mesial furcation were 2.5 mm and 2.2 mm for CBCT. The distal measurement of clinical examination was 2.7 mm and for CBCT was 2.44 mm. Conclusion: CBCT can be used as an adjunct to clinical furcation measurements and adds useful diagnostic information to assess trifurcation defects. In addition, CBCT limited field of view (FOV) can provide relatively high-resolution images at a reduced dose that is comparable to two-dimensional imaging.

Histologic Evaluation of Artificial Floors Under MTA and Nano-Filled Resin-Modified Glass Ionomer Used to Repair Furcation Perforations in Dogs.

Objective: This study aimed to compare the tissue reaction of two repair materials for furcation perforations, nano-filled resin modified glass ionomer (Nano-FRMGI) and mineral trioxide aggregate (MTA), used with or without an artificial floor. Methods: A total of 96 teeth in 6 dogs were used for this study. After access cavities, root canals were prepared and obturated with gutta percha using cold lateral condensation technique. Perforations were then created on the floors of the pulp chambers. The perforations divided into four groups n=24/group that were sealed with MTA alone, MTA with calcium sulphate artificial floor (CSAF), FRMGI alone and Nano-FRMGI with CSAF. All access cavities were filled with composite resin. Two dogs were sacrificed at 1, 3, and 6 month. The experimental tooth along with the surrounding alveolar bone were cut in block sections and histologically evaluated for tissue response. Data were analyzed by Chi-square (P≤0.05). Results: MTA and MTA with CSAF showed more bone and cementum apposition when compared to Nano-FRMGI at 6-month interval. MTA and MTA with CSAF showed less bone resorption, epithelium proliferation and inflammation compared to Nano-FRMGI at 6-month interval. Conclusion: MTA with CSAF or MTA-alone show better outcomes in the repair of pulp chamber floor perforation.

Antagonistic interaction between Ezh2 and Arid1a coordinates root patterning and development via Cdkn2a in mouse molars.

Patterning is a critical step during organogenesis and is closely associated with the physiological function of organs. Tooth root shapes are finely tuned to provide precise occlusal support to facilitate the function of each tooth type. However, the mechanism regulating tooth root patterning and development is largely unknown. In this study, we provide the first in vivo evidence demonstrating that Ezh2 in the dental mesenchyme determines patterning and furcation formation during dental root development in mouse molars. Mechanistically, an antagonistic interaction between epigenetic regulators Ezh2 and Arid1a controls Cdkn2a expression in the dental mesenchyme to regulate dental root patterning and development. These findings indicate the importance of balanced epigenetic regulation in determining the tooth root pattern and the integration of roots with the jaw bones to achieve physiological function. Collectively, our study provides important clues about the regulation of organogenesis and has general implications for tooth regeneration in the future.

Injectable chitosan/ß-glycerophosphate hydrogels with sustained release of BMP-7 and ornidazole in periodontal wound healing of class III furcation defects.

The aim of this study was to determine the effect of bone morphogenetic protein-7 (BMP-7) and ornidazole (ORN) loaded Chitosan/ß-glycerophosphate (CS/ß-GP) thermosensitive hydrogels on periodontal regeneration. CS/ß-GP hydrogels with and without BMP-7 and ORN were compared with respect to physicochemical properties, release kinetics, and antimicrobial activity in vitro, and periodontal regeneration properties in class III furcation defects in beagles via radiography, histology including immunohistochemical staining of osteoblasts and osteoclasts, and histometric analysis. CS/ß-GP hydrogels with and without BMP-7 and ORN had comparable physicochemical properties and gelation kinetics. Release kinetics showed that the hydrogels were capable of stable and sustained release of BMP-7 and ORN. The hydrogels loaded with ORN exhibited obvious antimicrobial activity against P. gingivalis. Histometric analysis quantitatively showed significantly more new bone and cementum, and less connective tissue in defects implanted with BMP-7 loaded hydrogels compared with hydrogels without BMP-7. The number of osteoclasts reduced significantly in the CS/BMP-7/ORN and CS/BMP-7 groups, while the number of osteoblasts increased significantly in these groups. Our findings showed that BMP-7 and ORN conferred additional advantages to the CS/ß-GP hydrogel in periodontal regeneration and suggest potential consideration of this approach for periodontal therapy.

Correlation of radiovisuographic analysis of interdental and interradicular bone loss in furcation involvement of mandibular first molars: A retrospective study.

BACKGROUND AND OBJECTIVES: The presence of furcation involvement represents a formidable problem in the treatment of periodontal disease. Advances in radiographic analysis such as radiovisuographic (RVG) aid in the early diagnosis and treatment planning, which is critical for long-term success. The present investigation aims to correlate the interdental and interradicular bone loss in chronic periodontitis patients so as to explore the potential of interdental bone loss as a rough approximate screening tool for early furcation diagnosis in mandibular first molar. MATERIALS AND METHODS: RVG radiographs with furcation radiolucency in mandibular first molars were selected. The morphometric measurements of mesial, distal interdental bone loss, and interradicular bone loss in mandibular first molars were recorded using RVG. The correlation between mesial and distal interdental bone loss and interradicular bone loss was analyzed. RESULTS: In this retrospective investigation, it was observed that distal interdental bone loss was not significantly different when compared with mesial interdental bone loss. The interradicular bone loss was significantly different when compared with mesial interdental bone loss, whereas on analysis between distal interdental bone loss and interradicular bone loss was also found to be statistically significant. INTERPRETATION AND CONCLUSION: Interdental bone loss was found to be associated with progressive bone destruction in furcation area which suggests that early detection of interdental bone loss can be helpful in predicting future interradicular bone loss.

A retrospective study on molar furcation assessment via clinical detection, intraoral radiography and cone beam computed tomography.

BACKGROUND: Accurate determination of bone loss at the molar furcation region by clinical detection and intraoral radiograph is challenging in many instances. Cone beam computed tomography (CBCT) is expected to open a new horizon in periodontal assessment. The purpose of this study was to compare and correlate accuracy of molar furcation assessment via clinical detection, intraoral radiography and CBCT images. METHODS: Eighty-three patients with chronic periodontitis who had existing CBCT scans were included. Furcation involvement was assessed on maxillary and mandibular first molars. Periodontal charts (modified Glickman's classification), intraoral (periapical and/or bitewing) radiographs (recorded as presence or absence) and axial CBCT reconstructions were used to evaluate furcation involvement on buccal and palatal/lingual sites. The correlation of furcation assessment by the three methods was evaluated by Pearson analysis. RESULTS: There were significant correlations (p < 0.05) between clinical detection and intraoral radiography, clinical detection and CBCT, as well as intraoral radiography and CBCT at all the measured sites (r values range between 0.230 to 0.644). CBCT generally exhibited higher correlation with clinical detection relative to intraoral radiography, especially at distal palatal side of maxillary first molar (p < 0.05). In addition, CBCT provided more accurate assessment, with bone loss measurement up to 2 decimals in millimeters, whereas clinical detection had 3 classes and the intraoral radiographs usually only detected the presence of furcation involvement in Glickman Class 2 and 3. CONCLUSIONS: This study validates that CBCT is a valuable tool in molar furcation assessment in addition to clinical detection and intraoral radiography.

The effect of horizontal and vertical furcation involvement on molar survival: A retrospective study.

BACKGROUND: Periodontal involvement of the furcation area (furcation involvement, FI) has been reported to confer molars a higher risk of tooth loss. AIMS: The aim of this retrospective analysis was to assess the effect of FI on disease progression and tooth loss in molars of patients with chronic periodontitis undergoing supportive periodontal therapy (SPT) in a UK private practice setting. MATERIALS AND METHODS: Six-hundred and thirty-three molars were analysed in 100 chronic periodontitis patients treated with active periodontal therapy (APT) and followed up in SPT for at least 5 years. Molars were treated with a combination of resective, regenerative or conservative approaches, according to the different clinical needs. RESULTS: Twenty-three molars were extracted during APT and a further 23 were lost during SPT. Multivariable analysis showed that both horizontal FI and vertical furcation component were associated with increased risk of tooth loss during SPT (OR 5.26, 95% CI: 1.46-19.03, p = .012 and OR 9.83, 95% CI: 1.83-50.11, p = .006, respectively). CONCLUSION: Attention should be placed on both horizontal and vertical FI in molars, owing to their association with tooth loss during SPT.

Vertical subclassification predicts survival of molars with class II furcation involvement during supportive periodontal care.

BACKGROUND: Furcation involvement is a major predictor of tooth survival. Focus has so far been on the predictive value of the horizontal component of furcation involvement. Residual periodontal support on each of the roots is likely to play a major role on retention of the furcated molar. Aim of this clinical audit study was to preliminarily assess the impact of vertical subclassification on tooth retention. METHODS: Tooth retention of class II furcated molars in 200 consecutive patients compliant with periodontal supportive care for a minimum of 10 years was retrospectively evaluated in a single practice. Randomly selected furcated molars were retrospectively diagnosed in terms of vertical subclassification (residual periodontal support on the most compromised root), and time to tooth extraction/loss was determined in clinical records. Kaplan-Meier survival curves were constructed. RESULTS: Ten-year survival of molar with class II furcation involvement was 52.5%. Survival was 91% for subclass A, 67% for subclass B and 23% for subclass C. Mean years of survival were 9.5-10.1, 8.5-9.3 and 6-7.3 for subclasses A, B and C, respectively. Tests of equality of the survival distributions showed highly significant differences in all portions of the curve (p < .001). Stratified analyses by smoking showed significant differences for the two groups (p < .001). Hazard rates for tooth extraction/loss were 4.2 and 14.7 for subclasses B and C, respectively. CONCLUSIONS: Residual periodontal support assessed as vertical subclassification of furcation involvement seems to be a good predictor of survival of molar with class II horizontal furcation. This has implication for prognosis, treatment planning and development of effective molar retention strategies.

Furcation Perforation: Periradicular Tissue Response to Biodentine as a Repair Material by Histopathologic and Indirect Immunofluorescence Analyses.

INTRODUCTION: The purpose of this study was to evaluate the in vivo response of periradicular tissues after sealing of furcation perforations with Biodentine, mineral trioxide aggregate (MTA), and gutta-percha by means of histopathologic and indirect immunofluorescence analyses. METHODS: Thirty teeth of 3 dogs were divided into 3 groups: Biodentine (n = 14 teeth), MTA (negative control, n = 10 teeth), and gutta-percha (positive control, n = 6 teeth). After endodontic treatment, perforations were made on the center of the pulp chamber floor and filled with the materials. After 120 days, the animals were killed, and blocks containing the teeth and periradicular tissues were processed histotechnically for histopathologic semiquantitative (new mineralized tissue formation and bone resorption at the perforation site) and quantitative (thickness and area of newly formed mineralized tissue and number of inflammatory cells) analyses and RUNX2 immunofluorescence assay. Data were analyzed by χ2, Fisher exact test, Mann-Whitney test, one-way analysis of variance, Kruskal-Wallis test, and Dunn posttest (α = 0.05). RESULTS: MTA and Biodentine induced the formation of significantly more new mineralized tissue (P < .0001) than gutta-percha, which did not induce the formation of mineralized tissue in any case. Complete sealing of the perforations was more frequent with MTA, which formed mineralized tissue with greater thickness and area. Biodentine and MTA exhibited no bone resorption in the furcation region, fewer inflammatory cells, and greater RUNX2 immunostaining intensity than gutta-percha. CONCLUSIONS: Although MTA presented higher frequency of complete sealing and greater thickness and area of newly formed mineralized tissue, Biodentine also had good histopathologic results and can be considered as an adequate furcation perforation repair material.

The sphingosine-1-phosphate receptor 1 binding molecule FTY720 inhibits osteoclast formation in rats with ligature-induced periodontitis.

BACKGROUND AND OBJECTIVE: Osteoclast precursors (OPs) re-migrate from the bone surface into blood vessels through sphingosine-1-phosphate receptor 1 (S1PR1) expression. T cells also express S1PR1, mediating their migration from the lymph nodes into blood vessels. OP and T-cell migration are one of the sequential steps related to osteoclast formation. To characterize the role of S1PR1 in osteoclast formation induced by periodontitis, we investigated the effect of S1PR1-binding molecule FTY720 (FTY) on the number of OPs and T cells in periodontal tissue and peripheral blood of rats with ligature-induced periodontitis. MATERIAL AND METHODS: Rats were divided into four groups; control (Con), FTY, periodontitis (Peri), and periodontitis+FTY (Peri+FTY) groups. Ligatures were placed around the first molars in the left and right mandibles. The rats were intraperitoneally injected with vehicle or 3 mg/kg FTY daily until they were killed. The number of osteoclasts and cluster of differentiation (CD)11b, CD3 and receptor activator of NF-κB ligand (RANKL)-positive cells in first molar furcation were counted by tartrate-resistant acid phosphatase or immunohistochemistry staining. The number of CD11b- and CD3-positive cells in peripheral blood was estimated by flow cytometry. RESULTS: The number of osteoclasts in the Peri group was higher than Con, Peri+FTY and FTY groups (p < 0.05) and CD11b, CD3 and RANKL-positive cells were also higher in the Peri group than other groups in furcation (p < 0.05). While CD11b-positive cells in furcation of the Peri+FTY group were lower than the Peri group (p < 0.05), they were higher in peripheral blood (p < 0.05). Dissimilar to CD11b-positive cells, CD3-positive cells in the Peri+FTY group were lower in peripheral blood as well as furcation than the Peri group (p < 0.05). RANKL-positive cells in furcation of the Peri+FTY group were also lower than Peri group (p < 0.05). CONCLUSION: These results indicate that FTY may facilitate re-migration of OPs from the alveolar bone surface into blood vessels, blocking T-cell migration from the lymph nodes into blood vessels and subsequently reducing osteoclast formation induced by periodontitis. This suggests that S1PR1-S1P binding may play a role in osteoclast formation of periodontitis by modulating OP and T-cell migration.

Comparison of Two Base Materials Regarding Their Effect on Root Canal Treatment Success in Primary Molars with Furcation Lesions.

Introduction. The aim of this study was to compare MTA with another base material, IRM, which is generally used on pulpal floor after root canal treatment, regarding their effect on the success of root canal treatment of primary teeth with furcation lesions. Materials and Methods. Fifty primary teeth with furcation lesions were divided into 2 groups. Following root canal treatment, the pulpal floor was coated with MTA in the experimental group and with IRM in the control group. Teeth were followed up considering clinical (pain, pathological mobility, tenderness to percussion and palpation, and any soft tissue pathology and sinus tract) and radiographical (pathological root resorption, reduced size or healing of existing lesion, and absence of new lesions at the interradicular or periapical area) criteria for 18 months. For the statistical analysis, Fisher's exact test and Pearson's chi-square tests were used and a p value of <0.05 was considered to be statistically significant. Results. Although there were no statistically significant differences between two groups in terms of treatment success, lesions healed significantly faster in the MTA group. Conclusion. In primary teeth with furcation lesions, usage of MTA on the pulpal floor following root canal treatment can be a better alternative since it induced faster healing.

Clinical concepts for regenerative therapy in furcations.

Furcation involvements present one of the greatest challenges in periodontal therapy because furcation-involved molar teeth respond less favorably to conventional periodontal therapy compared with noninvolved molar or nonmolar teeth. Various regenerative procedures have been proposed and applied with the aim of eliminating the furcation defect or reducing the furcation depth. An abundance of studies and several systematic reviews have established the effectiveness of membrane therapy (guided tissue regeneration) for buccal Class II furcation involvement of mandibular and maxillary molars compared with open flap surgery. Bone grafts/substitutes may enhance the results of guided tissue regeneration. However, complete furcation closure is not a predictable outcome. Limited data and no meta-analyses are available on the effects of enamel matrix proteins for furcation regeneration. Enamel matrix protein therapy has demonstrated clinical improvements in the treatment of buccal Class II furcation defects in mandibular molars; however, complete closure of the furcation lesion is achieved only in a minority of cases. Neither guided tissue regeneration nor enamel matrix protein therapy have demonstrated predictable results for approximal Class II and for Class III furcations. Promising preclinical data from furcation regeneration studies in experimental animals is available for growth factor- and differentiation factor-based technologies, but very limited data are available from human clinical studies. Although cell-based therapies have received considerable attention in regenerative medicine, their experimental evaluation in the treatment of periodontal furcation lesions is at a very early stage of development. In summary, the indications and the limitations for currently available treatment modalities for furcation defects are well established. New regenerative treatments are clearly needed to improve the predictability of a complete resolution of furcation defects.

Localization of RANK, RANKL and osteoprotegerin during healing of surgically created periodontal defects in sheep.

BACKGROUND AND OBJECTIVE: Modeling of periodontal bone regeneration in a large animal enables better examination of the spatial and temporal regulation of osteogenesis and the remodeling of the healing defect. RANK, RANKL and osteoprotegerin (OPG) are known to be important regulators of bone healing. The aim of this study was to create periodontal defects surgically in a large animal model and to examine bone regeneration and the expression of RANK, RANKL and OPG proteins in the defect site during bone regeneration. MATERIAL AND METHODS: Periodontal defects were made in the furcation of the second mandibular premolar of sheep. Wound healing was examined 6 h, and 1, 4 and 6 wk after surgery and in control tissue. The teeth and defect region were decalcified and paraffin embedded. Immunohistochemistry for RANK, RANKL and OPG was conducted. Osteoclasts were identified using TRAP staining. RESULTS: The defects were examined at different time points after surgery and by 6 wk the defect region had fully regenerated with new bone, albeit less dense than that in the unwounded controls. RANK-positive osteoclasts were present at the edge of the wound from week 1 and were found within the defect at week 6, corresponding to osteoclast activation and bone remodeling. RANKL staining increased from week 1 compared with unwounded tissue, and peaked at 4 and 6 wk, as the osteoblast numbers increased. At the same time, OPG immunostaining was high in controls and at week 6, suggesting that it may act to block RANKL and control the bone remodeling within the defect. CONCLUSION: Distinctive temporal and spatial expression patterns for RANK, RANKL and OPG proteins were observed during healing of surgically created periodontal wounds in a sheep model. The research identifies possible therapeutic approaches to periodontal bone repair via modulation of these members of the tumor necrosis factor family.

The effect of brain-derived neurotrophic factor on periodontal furcation defects.

This study aimed to observe the regenerative effect of brain-derived neurotrophic factor (BDNF) in a non-human primate furcation defect model. Class II furcation defects were created in the first and second molars of 8 non-human primates to simulate a clinical situation. The defect was filled with either, Group A: BDNF (500 µg/ml) in high-molecular weight-hyaluronic acid (HMW-HA), Group B: BDNF (50 µg/ml) in HMW-HA, Group C: HMW-HA acid only, Group D: empty defect, or Group E: BDNF (500 µg/ml) in saline. The healing status for all groups was observed at different time-points with micro computed tomography. The animals were euthanized after 11 weeks, and the tooth-bone specimens were subjected to histologic processing. The results showed that all groups seemed to successfully regenerate the alveolar buccal bone, however, only Group A regenerated the entire periodontal tissue, i.e., alveolar bone, cementum and periodontal ligament. It is suggested that the use of BDNF in combination with a scaffold such as the hyaluronic acid in periodontal furcation defects may be an effective treatment option.

Cigarette smoke inhalation increases the alveolar bone loss caused by primary occlusal trauma in a rat model.

BACKGROUND AND OBJECTIVE: Occlusal trauma (OT) and smoking are both factors that alter alveolar bone metabolism and therefore could synergistically act on alveolar bone loss. The aim of this experimental study was to evaluate the influence of short-term cigarette smoke inhalation (CSI) on inter-radicular alveolar bone loss promoted by primary OT in a rat model. MATERIAL AND METHODS: Forty-eight animals were randomly assigned to one of three groups based on treatment type: OT + CSI (n = 16), animals were exposed to CSI three times per day, for 8 min per exposure, and they concomitantly received unilateral vertical augmentation creating an occlusal interference inducing experimental OT; OT (n = 16), animals received only unilateral vertical augmentation; negative control (NC; n = 16), animals maintained for equal periods to achieve periodontal baseline values of periodontal ligament dimension. Each group was divided into two subgroups (n = 8) based on treatment length: 7 or 14 d. RESULTS: After 7 d, the OT + CSI group exhibited significantly higher bone loss compared to the NC group (p = 0.0022). After 14 d, the OT (p < 0.0001) and OT + CSI (p < 0.0001) groups presented significantly higher bone loss compared to the NC group, and OT + CSI resulted in significantly higher bone loss than OT alone (p = 0.0241). The number of tartrate-resistant acid phosphatase-positive cells on the linear surface of the bone crest after 7 d was significantly higher in the OT + CSI group as compared to the NC and OT groups (p < 0.0001 and p = 0.0045, respectively) and remained significantly higher in the OT + CSI group after 14 d, compared to the OT group (p < 0.0001). CONCLUSION: Short-term CSI increases early bone loss in association with OT after 7 d, and this worsens in severity after 14 d of exposure.

Regeneration of the periodontium using enamel matrix derivative in combination with an injectable bone cement.

OBJECTIVES: Enamel matrix derivative (EMD) has proven to enhance periodontal regeneration; however, its effect is mainly restricted to the soft periodontal tissues. Therefore, to stimulate not only the soft tissues, but also the hard tissues, in this study EMD is combined with an injectable calcium phosphate cement (CaP; bone graft material). The aim was to evaluate histologically the healing of a macroporous CaP in combination with EMD. MATERIALS AND METHODS: Intrabony, three-wall periodontal defects (2 × 2 × 1.7 mm) were created mesial of the first upper molar in 15 rats (30 defects). Defects were randomly treated according to one of the three following strategies: EMD, calcium phosphate cement and EMD, or left empty. The animals were killed after 12 weeks, and retrieved samples were processed for histology and histomorphometry. RESULTS: Empty defects showed a reparative type of healing without periodontal ligament or bone regeneration. As measured with on a histological grading scale for periodontal regeneration, the experimental groups (EMD and CaP/EMD) scored equally, both threefold higher compared with empty defects. However, most bone formation was measured in the CaP/EMD group; addition of CAP to EMD significantly enhanced bone formation with 50 % compared with EMD alone. CONCLUSIONS: Within the limits of this animal study, the adjunctive use of EMD in combination with an injectable cement, although it did not affect epithelial downgrowth, appeared to be a promising treatment modality for regeneration of bone and ligament tissues in the periodontium. CLINICAL RELEVANCE: The adjunctive use of EMD in combination with an injectable cement appears to be a promising treatment modality for regeneration of the bone and ligament tissues in the periodontium.

Platelet-rich plasma in the treatment of Class II furcation defects: a histometrical study in dogs.

OBJECTIVE: This study was designed to evaluate the potential adjunctive benefits of platelet-rich plasma (PRP) when used with guided-tissue regeneration (GTR) and bioactive glass (BG) in the treatment of Class II furcation lesions. MATERIAL AND METHODS: Bilateral Class II furcation lesions were surgically created and allowed to become chronic in the mandibular third premolars of 9 dogs. The defects were randomly assigned to: A) GTR+BG and B) GTR+BG+PRP. Similar defects were created in the maxillary third premolars and received the same treatments after 45 days. Dogs were sacrificed 90 days after the first treatment. The histometric parameters evaluated were: connective tissue adaptation, new cementum, new bone, mineralized bone area, non-mineralized bone area, and residual BG particle area. RESULTS: Data analysis showed a superior length of new cementum and a greater mineralized bone area for group B in both periods (p<0.05). The non-mineralized bone area was greater in the control group (p<0.05) in both periods. CONCLUSION: Within the limits of this study, it can be concluded that the use of PRP in the treatment of Class II furcation defects may enhance the amount of new cementum and provide a more mineralized bone in a shorter period of time.