Periodontal tissue repair after sealing of the gap in vertical root fracture.

The aim of this study was to determine whether sealing of fracture gap using adhesive resin through the root canal can prevent inflammation of periodontal tissue, and resealing the incompletely sealed fracture gap from outside can resolve such inflammation in experimentally created vertical root fractures. Vertical root fractures were created in incisor of beagles. In the experimental group, the fracture gap was sealed through the root canal with adhesive resin. After 5 weeks, sites with the clinical attachment level ≥4 mm were further divided randomly into the poor-replanting group and the poor-untreated group. In the poor-replanting group, the tooth was extracted and replanted after resealing the fracture gap with adhesive resin from the outer surface. Sites with clinical attachment level ≤3 mm after 5 weeks were considered as the satisfactory group. The poor-untreated group and the satisfactory group were subjected to no further treatment. The clinical attachment level was evaluated at baseline and after 2, 5, and 9 weeks. After 9 weeks, histological measurements were made to determine the length of the epithelial downgrowth and the area of alveolar bone resorption. The clinical attachment level and the area of bone resorption were significantly smaller in the poor-replanting group and the satisfactory group than in the poor-untreated group (p < 0.05). The results indicate the possibility that periodontal inflammation along the fracture line can be prevented and improved if the fracture gap is sealed.

Regulation of osteoblastic differentiation by the proteasome inhibitor bortezomib.

In eukaryotic cells, degradation of most intracellular proteins is carried out by the ubiquitin-proteasome pathway. Recent investigations suggest that bone metabolism is also regulated by this pathway. The clinical efficacy of bortezomib, a 26S proteasome inhibitor used as an anticancer drug, has been linked to an increase in bone formation. In this study, we show that proteasome inhibitors induce expression of osteoblastic differentiation-related genes such as osteocalcin and alkaline phosphatase in C2C12 cells. In contrast, myogenic differentiation is inhibited. Among the proteasome inhibitors tested, bortezomib induced the greatest increase in osteocalcin expression. Although these effects were similar to that of bone morphogenetic protein (BMP) 2, proteasome inhibitors did not induce transcriptional activity of Smad1/4-dependent reporter or BMP2 signaling target gene expression. Transient transfection of osteocalcin promoter-luciferase constructs with bortezomib resulted in an increase in luciferase activity. Mutation of OSE2, but not OSE1, sites of the osteocalcin promoter diminished the bortezomib-induced activity. Also, Runx2 binding activity and protein levels were induced by bortezomib treatment. These results suggest that the bortezomib induces osteoblastic differentiation by modifying the activity of Runx2 and that the function of the proteasome in controlling degradation of differentiation-related transcription factors plays an important role in osteoblast differentiation.

Immunolocalization of sclerostin synthesized by osteocytes in relation to bone remodeling in the interradicular septa of ovariectomized rats.

This study aimed at elucidating whether estrogen deficiency would affect the synthesis of an osteocyte-derived factor, sclerostin, in the mesial region of alveolar bone. Eight 9-week-old Wistar female rats were ovariectomized (OVX) and eight other rats were Sham-operated (Sham). After 4 weeks, the interradicular septa of mandibular first molar were embedded in paraffin and then histochemically examined. Sclerostin-positive osteocytes were located in the superficial layer of the mesial region of Sham bones, whereas the OVX mesial region showed less sclerostin-reactive osteocytes. There was no significant difference in the distribution of estrogen receptor α and terminal deoxynucleotidyl transferase-mediated deoxyuridinetriphosphate nick end-labeling -positive cells in the groups studied. The Sham mesial region featured many osteoclasts, and OVX specimens showed numerous osteoclasts in association with intense immunolabeling of the receptor activator of the nuclear factor kB ligand. Contrary to the observations in Sham specimens, a complex meshwork of cement lines was seen in the OVX mesial region, accompanied by an irregularly distributed osteocytic lacunar-canalicular system. In conclusion, estrogen deficiency appears to inhibit osteocyte-derived sclerostin synthesis in the mesial region of the interradicular septum, in a process that seems to be mediated by accelerated bone remodeling rather than by direct effects on osteocytes.

A large-scale observational study to investigate the current status of diabetic complications and their prevention in Japan (JDCP study 6): baseline dental and oral findings.

Japan Diabetes Complication and Prevention prospective (JDCP) study was conducted to examine the association between glycemic control and oral conditions in a large database of Japanese patients with diabetes. It included a total of 6099 patients with diabetes (range, 40-75 years) who had been treated as outpatients between 2007 and 2009. The mean number of present teeth at baseline was 19.8 and women with type 2 diabetes had fewer teeth than men with type 2 diabetes. Within the previous year, 17% of all patients had lost teeth. At baseline, 32% had experienced gingival swelling, 69% had brushed more than twice a day, 37% had used interdental cleaning aids, and 43% had undergone regular dental checkups. Multiple logistic regression analysis indicated that type 1 patients with HbA1c ≥ 7.0% were at higher risk of having fewer than 20 teeth (odds ratio [OR] 2.38; 95% confidence interval [CI] 1.25-4.78), and type 2 patients with HbA1c ≥ 8.0% also were at high risk of having fewer than 20 teeth (OR 1.16; 95% CI 1.00-1.34), after adjustment for nine possible confounding factors. In conclusion, patients with diabetes were found to be at high risk of tooth loss, and the poorer the glycemic control, the higher the risk of tooth loss in these patients.

Association between self-efficacy and loss to follow-up in long-term periodontal treatment.

AIM: To examine whether or not oral health care-specific self-efficacy can predict loss to follow-up for long-term periodontal treatment. METHODS: Our prospective cohort study enrolled 144 patients with chronic periodontitis. Patient self-efficacy was assessed on the initial visit using the self-efficacy scale for self-care (SESS). Participants were then followed for 30 months from the onset of periodontal treatment. The loss to follow-up is the main outcome variable. Multiple logistic regression analysis was conducted to examine the association between self-efficacy for self-care and loss to follow-up for periodontal treatment. Gender, age, number of teeth, probing depth, plaque control record (PCR) value, PCR improvement rate, general self-efficacy scale score, and SESS score were used as the independent variables, and loss to follow-up as a dependent variable. RESULTS: A total of 67 patients were lost to follow-up over the course of the study. Compared with the high-scoring SESS group (60-75), the odds ratio of loss to follow-up for the middle- (54-59) and low-scoring groups (15-53) were 1.05 [95% confidence interval (CI): 0.36-3.07] and 4.56 (95% CI: 1.11-18.74), respectively. CONCLUSION: Assessment of oral health care-specific self-efficacy may be useful in predicting loss to follow-up in long-term periodontal treatment.

Development of the self-efficacy scale for maternal oral care.

PURPOSE: This study's purpose was to develop a task-specific self-efficacy scale for maternal oral care (SESMO) with reliability and validity. METHODS: A draft scale consisting of 36 items was designed and tested on 119 mothers at a dental clinic. Item analysis was performed to improve its accuracy by reducing the number of items. Internal consistency and test and retest stability were investigated. Concurrent validity was tested by examining associations of the SESMO score with the: general self-efficacy scale (GSES) score; number of decayed teeth; and frequency of tooth-brushing for children. Construct validity was examined by comparing the SESMO scores between mothers of children with caries at initial visit (Group 1) and those continuing regular dental checkups (Group 2). RESULTS: The item analysis selected 16 items for the SESMO. Alpha coefficient of the SESMO was 0.82. Significant correlation was observed between tests and retests (r=0.74). There were significant associations between the SESMO score and GSES score (r=0.39); number of decayed teeth (r=-0.33); and frequency of brushing children's teeth (r=0.66). Group 2 had a significantly higher SESMO score than Group 1 (P<.001). CONCLUSIONS: The SESMO showed high reliability and validity. This scale might endure with research applications in pediatric dental practice.

Influence of residual bone on recombinant human bone morphogenetic protein-2-induced periodontal regeneration in experimental periodontitis in dogs.

BACKGROUND: Previous studies reported that bone morphogenetic protein (BMP)-2 induced periodontal regeneration in animals. However, the effects of local host factors on bone formation when using recombinant human (rh)BMP-2 are unknown. The purpose of this study was to evaluate local conditions in recipient sites that affected periodontal regeneration following BMP implantation in experimentally induced horizontal defects in dogs. METHODS: Experimental periodontitis was induced in the maxillary and mandibular premolars of six male beagles. The recipient sites were divided into four quadrants (maxillary buccal, maxillary palatal, mandibular buccal, and mandibular lingual sites). A polymer-coated gelatin sponge (PGS; 3 x 3 x 2 mm) was impregnated with 7.2 mul rhBMP-2 solution. The recipient sites in each quadrant were treated with physiologic saline/PGS and rhBMP-2/PGS (rhBMP-2 at 7.2 mug/7.2 mul). The dogs were sacrificed 12 weeks post-surgery, and healing was evaluated histologically. RESULTS: Bone formation and connective tissue attachment were observed following rhBMP-2/PGS implantation. In the four recipient sites of the BMP-treated group, significant positive correlations were found between the width of residual bone and the height and area of regenerated bone (r = 0.791; r = 0.828; P <0.0001). The height of regenerated bone was also significantly correlated to the area (r = 0.891; P <0.0001). CONCLUSIONS: The width of residual bone was one of the clinical host factors that affected bone regeneration following BMP implantation. However, it did not affect connective tissue attachment, cementum regeneration, and downgrowth of junctional epithelium.

Bone perforation and placement of collagen sponge facilitate bone augmentation.

BACKGROUND: Bone perforation may induce bone marrow cell migration into a collagen sponge onlay implant. This study investigated the efficacy of bone perforation and collagen sponge onlay placement with regard to new bone formation. METHODS: One hundred sixty femurs of 80 Wistar male rats were used in four groups: bone perforation and sponge (PS) group: after perforating the femur, fibrillar and heat-denatured collagen (FC-HAC) sponges were placed on the femur; sponge (S) group: a FC-HAC sponge was placed directly on the femur without bone perforation; perforation (P) group: femur perforation without collagen sponge placement; and control (C) group: neither bone perforation nor sponge placement was used. Histologic and histomorphometric analyses were performed after the surgery. RESULTS: Numerous osteoblastic and fibroblastic cells were seen during the early repopulation in and at the periphery of the sponge in the PS group. These cells were seen only at the periphery of the sponge in the S group. In the PS group, angiogenesis was noted frequently, and it exhibited significantly greater new bone area compared to the other groups at days 14 and 28. CONCLUSION: The use of the FC-HAC sponge on the bone perforation area seemed to promote bone augmentation by possibly acting as a scaffold for the bone marrow cells as well as maintaining the space that is necessary for bone growth to occur.

Systematic cognitive behavioral approach for oral hygiene instruction: a short-term study.

OBJECTIVE: Determine whether a six-step behavioral cognitive method is more effective than traditional oral hygiene instruction. METHODS: Thirty-eight patients with chronic periodontitis were randomly assigned to two groups. The control group was given traditional oral hygiene instruction for 20 min. The intervention group received counseling by Farquhar's six-step method for 10 min after traditional oral hygiene instruction. In both groups, oral hygiene instruction was given once a week, and performed three times in total for 3 weeks. Clinical characteristics, deposition of dental plaque, frequency and duration of brushing, frequency of interdental cleaning and scores based on scale of "self-efficacy for brushing of the teeth" were compared in both groups. RESULTS: There were no differences between the two groups in clinical, demographic, behavioral and self-efficacy characteristics at the baseline examination. However after the third visit, the intervention group had a significantly higher self-efficacy, lower plaque index, longer brushing duration and higher frequency of inter-dental cleaning than those of the control group. Multiple regression analysis showed significant association of toothbrushing duration with self-efficacy for brushing of the teeth (p<0.001). CONCLUSION: The six-step method might be more effective for enhancing self-efficacy and behavioral change of oral hygiene than traditional oral hygiene instruction alone. PRACTICE IMPLICATIONS: Dentists and dental hygienists can use the six-step method for effective oral hygiene instruction.

Oral health care-specific self-efficacy assessment predicts patient completion of periodontal treatment: a pilot cohort study.

BACKGROUND: Whether patients complete periodontal treatment is an important matter of concern. Self-efficacy is the confidence of an individual that determines "how well he/she can take the actions necessary for producing certain results" and is a variable that forecasts behavior. This study examined whether oral health care-specific self-efficacy can predict patient completion of periodontal treatment. METHODS: A total of 140 subjects with mild to moderate chronic periodontitis (64 females and 76 males; 19 to 86 years of age; mean age: 51.7 +/- 15.7 years) participated in this study. Their self-efficacy was assessed using the self-efficacy scale for self-care (SESS) and the general self-efficacy scale (GSES) scores at the initial visit. SESS consists of three subscales: self-efficacy for dentist consultations, brushing of the teeth, and dietary habits. The subjects were classified into three groups: group 1 = 87 subjects who stayed in periodontal treatment and fulfilled maintenance criteria; group 2 = 17 subjects who stayed in periodontal treatment but did not fulfill criteria; and group 3 = 36 subjects who dropped out of periodontal treatment. Clinical and demographic characteristics and scores of GSES, SESS, and their subscales were compared among the three groups using the chi(2) and non-parametric multiple comparison tests. RESULTS: The mean age of the subjects in groups 1 and 2 was significantly greater than the mean age of the subjects in group 3. Groups 1 and 2 exhibited significantly deeper probing depths and higher scores for SESS and its subscale, self-efficacy for dentist consultations, than did group 3. CONCLUSION: Assessment of oral health care-specific self-efficacy is effective for the prediction of patient completion of periodontal treatment.

Hybrid layer seals the cementum/4-META/MMA-TBB resin interface.

Although 4-META/MMA-TBB resin has adhesive properties to dentin, and has been clinically used for the bonding treatment of vertically fractured roots and apicoectomy, there has not been any investigation on the adhesion of 4-META/MMA-TBB resin to cementum. The purpose of this in vitro study was to evaluate the bonding and the sealing ability of 4-META/MMA-TBB resin to cementum. Bovine root cementum and dentin surfaces were treated with a citric acid and ferric chloride solution, and the 4-META/MMA-TBB resin was applied on the treated surfaces before testing. The microtensile bond strength and the leakage levels obtained for the cementum were almost equal to those for the dentin. In SEM and TEM observations, a hybrid layer approximately 2-3 microm in thickness was observed at the interface between the resin and the cementum. It is concluded that 4-META/MMA-TBB resin adhered to cementum via a hybrid layer on cementum, as previously reported for dentin.

Effects of dose of recombinant human BMP-2 on bone formation at palatal sites in young and old rats.

This study was designed to examine the effects of dose of recombinant human BMP-2 (rhBMP-2) on bone formation at palatal sites in 10-week-old (10w) and 70-week-old (70w) rats, when combined with a polylactate-polyglycolate copolymer/gelatine sponge (PGS). New bone formation was observed at six weeks after implantation. In the 10w rats, thickness of new bone (TNB) increased as the dosage increased from 0 microg to 4 microg, and decreased significantly as the dosage increased from 8 microg to 24 microg. In contrast, in the 70w rats, TNB increased as the dosage increased from 0 microg to 16 microg, and did not significantly change as the dosage increased from 16 microg to 24 microg. These results suggest that the most effective dosage of rhBMP-2 for induction of bone formation varies according to age.

Dose effects of beta-tricalcium phosphate nanoparticles on biocompatibility and bone conductive ability of three-dimensional collagen scaffolds.

Three-dimensional collagen scaffolds coated with beta-tricalcium phosphate (ß-TCP) nanoparticles reportedly exhibit good bioactivity and biodegradability. Dose effects of ß-TCP nanoparticles on biocompatibility and bone forming ability were then examined. Collagen scaffold was applied with 1, 5, 10, and 25 wt% ß-TCP nanoparticle dispersion and designated TCP1, TCP5, TCP10, and TCP25, respectively. Compressive strength, calcium ion release and enzyme resistance of scaffolds with ß-TCP nanoparticles applied increased with ß-TCP dose. TCP5 showed excellent cell-ingrowth behavior in rat subcutaneous tissue. When TCP10 was applied, osteoblastic cell proliferation and rat cranial bone augmentation were greater than for any other scaffold. The bone area of TCP10 was 7.7-fold greater than that of non-treated scaffold. In contrast, TCP25 consistently exhibited adverse biological effects. These results suggest that the application dose of ß-TCP nanoparticles affects the scaffold bioproperties; consequently, the bone conductive ability of TCP10 was remarkable.

Site-level progression of periodontal disease during a follow-up period.

Periodontal disease is assessed and its progression is determined via observations on a site-by-site basis. Periodontal data are complex and structured in multiple levels; thus, applying a summary statistical approach (i.e., the mean) for site-level evaluations results in loss of information. Previous studies have shown the availability of mixed effects modeling. However, clinically beneficial information on the progression of periodontal disease during the follow-up period is not available. We conducted a multicenter prospective cohort study. Using mixed effects modeling, we analyzed 18,834 sites distributed on 3,139 teeth in 124 patients, and data were collected 5 times over a 24-month follow-up period. The change in the clinical attachment level (CAL) was used as the outcome variable. The CAL at baseline was an important determinant of the CAL changes, which varied widely according to the tooth surface. The salivary levels of periodontal pathogens, such as Porphyromonas gingivalis and Aggregatibacter actinomycetemcomitans, were affected by CAL progression. "Linear"- and "burst"-type patterns of CAL progression occurred simultaneously within the same patient. More than half of the teeth that presented burst-type progression sites also presented linear-type progression sites, and most of the progressions were of the linear type. Maxillary premolars and anterior teeth tended to show burst-type progression. The parameters identified in this study may guide practitioners in determining the type and extent of treatment needed at the site and patient levels. In addition, these results show that prior hypotheses concerning "burst" and "linear" theories are not valid.

Graphene oxide scaffold accelerates cellular proliferative response and alveolar bone healing of tooth extraction socket.

Graphene oxide (GO) consisting of a carbon monolayer has been widely investigated for tissue engineering platforms because of its unique properties. For this study, we fabricated a GO-applied scaffold and assessed the cellular and tissue behaviors in the scaffold. A preclinical test was conducted to ascertain whether the GO scaffold promoted bone induction in dog tooth extraction sockets. For this study, GO scaffolds were prepared by coating the surface of a collagen sponge scaffold with 0.1 and 1 µg/mL GO dispersion. Scaffolds were characterized using scanning electron microscopy (SEM), physical testing, cell seeding, and rat subcutaneous implant testing. Then a GO scaffold was implanted into a dog tooth extraction socket. Histological observations were made at 2 weeks postsurgery. SEM observations show that GO attached to the surface of collagen scaffold struts. The GO scaffold exhibited an interconnected structure resembling that of control subjects. GO application improved the physical strength, enzyme resistance, and adsorption of calcium and proteins. Cytocompatibility tests showed that GO application significantly increased osteoblastic MC3T3-E1 cell proliferation. In addition, an assessment of rat subcutaneous tissue response revealed that implantation of 1 µg/mL GO scaffold stimulated cellular ingrowth behavior, suggesting that the GO scaffold exhibited good biocompatibility. The tissue ingrowth area and DNA contents of 1 µg/mL GO scaffold were, respectively, approximately 2.5-fold and 1.4-fold greater than those of the control. Particularly, the infiltration of ED2-positive (M2) macrophages and blood vessels were prominent in the GO scaffold. Dog bone-formation tests showed that 1 µg/mL GO scaffold implantation enhanced bone formation. New bone formation following GO scaffold implantation was enhanced fivefold compared to that in control subjects. These results suggest that GO was biocompatible and had high bone-formation capability for the scaffold. The GO scaffold is expected to be beneficial for bone tissue engineering therapy.

A Novel Regenerative Technique Combining Bone Morphogenetic Protein-2 With Fibroblast Growth Factor-2 for Circumferential Defects in Dog Incisors.

BACKGROUND: Periodontal regeneration of incisors is necessary for esthetic recovery. A novel regenerative method combining bone morphogenetic protein (BMP)-2 and fibroblast growth factor (FGF)-2 was developed. The purpose of this study is to evaluate periodontal healing, including root coverage, in circumferential defects of incisors. METHODS: Fifty incisors in five beagles were used. After circumferential defects were surgically created, each group, consisting of ten recipient sites, received: 1) a double layer with FGF-2 (2 µg)/collagen as inner layer and BMP-2 (4 µg)/collagen as outer layer (FB-DL group); 2) collagen impregnated with both FGF-2 (2 µg) and BMP-2 (4 µg) (FB-M group); 3) BMP-2 (4 µg)/collagen (B group); 4) FGF-2 (4 µg)/collagen (F group); or 5) collagen (C group). Dogs were sacrificed 8 weeks post-surgery, and healing was evaluated histologically. RESULTS: The three groups treated with BMP-2 showed enhanced new bone formation compared with control and F groups (P < 0.05). Furthermore, connective tissue attachment with cementum regeneration in the FB-DL group was significantly greater than in FB-M and B groups (P <0.05). Ankylosis in the FB-DL group was significantly less than in FB-M and B groups (P <0.05). Gingival recession was inhibited significantly better in FB-DL and FB-M groups compared with control and B groups. CONCLUSION: These data support development of a double-layer method combining BMP-2 and FGF-2 as a therapeutic approach to periodontal regeneration at incisors with horizontal circumferential defects.

Collagen Hydrogel Scaffold and Fibroblast Growth Factor-2 Accelerate Periodontal Healing of Class II Furcation Defects in Dog.

OBJECTIVE: Collagen hydrogel scaffold exhibits bio-safe properties and facilitates periodontal wound healing. However, regenerated tissue volume is insufficient. Fibroblast growth factor-2 (FGF2) up-regulates cell behaviors and subsequent wound healing. We evaluated whether periodontal wound healing is promoted by application of collagen hydrogel scaffold in combination with FGF2 in furcation defects in beagle dogs. METHODS: Collagen hydrogel was fabricated from bovine type I collagen with an ascorbate-copper ion cross-linking system. Collagen hydrogel was mingled with FGF2 and injected into sponge-form collagen. Subsequently, FGF2 (50 µg)/collagen hydrogel scaffold and collagen hydrogel scaffold alone were implanted into class II furcation defects in dogs. In addition, no implantation was performed as a control. Histometric parameters were assessed at 10 days and 4 weeks after surgery. RESULT: FGF2 application to scaffold promoted considerable cell and tissue ingrowth containing numerous cells and blood vessel-like structure at day 10. At 4 weeks, reconstruction of alveolar bone was stimulated by implantation of scaffold loaded with FGF2. Furthermore, periodontal attachment, consisting of cementum-like tissue, periodontal ligament-like tissue and Sharpey's fibers, was also repaired, indicating that FGF2-loaded scaffold guided self-assembly and then re-established the function of periodontal organs. Aberrant healing, such as ankylosis and root resorption, was not observed. CONCLUSION: FGF2-loaded collagen hydrogel scaffold possessed excellent biocompatibility and strongly promoted periodontal tissue engineering, including periodontal attachment re-organization.

Randomized Placebo-Controlled and Controlled Non-Inferiority Phase III Trials Comparing Trafermin, a Recombinant Human Fibroblast Growth Factor 2, and Enamel Matrix Derivative in Periodontal Regeneration in Intrabony Defects.

We investigated the efficacy, safety, and clinical significance of trafermin, a recombinant human fibroblast growth factor (rhFGF)-2, for periodontal regeneration in intrabony defects in Phase III trials. Study A, a multicenter, randomized, double-blind, placebo-controlled study, was conducted at 24 centers. Patients with periodontitis with 4-mm and 3-mm or deeper probing pocket depth and intrabony defects, respectively, were included. A total of 328 patients were randomly assigned (2:1) to receive 0.3% rhFGF-2 or placebo, and 323 patients received the assigned investigational drug during flap surgery. One of the co-primary endpoints, the percentage of bone fill at 36 weeks after drug administration, was significantly greater in the rhFGF-2 group at 37.131% (95% confidence interval [CI], 32.7502 to 41.5123; n = 208) than it was in the placebo group at 21.579% (95% CI, 16.3571 to 26.8011; n = 100; p < 0.001). The other endpoint, the clinical attachment level regained at 36 weeks, was not significantly different between groups. Study B, a multicenter, randomized, blinded (patients and evaluators of radiographs), and active-controlled study was conducted at 15 centers to clarify the clinical significance of rhFGF-2. Patients with 6-mm and 4-mm or deeper probing pocket depth and intrabony defects, respectively, were included. A total of 274 patients were randomly assigned (5:5:2) to receive rhFGF-2, enamel matrix derivative (EMD), or flap surgery alone. A total of 267 patients received the assigned treatment during flap surgery. The primary endpoint, the linear alveolar bone growth at 36 weeks, was 1.927 mm (95% CI, 1.6615 to 2.1920; n = 108) in the rhFGF-2 group and 1.359 mm (95% CI, 1.0683 to 1.6495; n = 109) in the EMD group, showing non-inferiority (a prespecified margin of 0.3 mm) and superiority of rhFGF-2 to EMD. Safety problems were not identified in either study. Therefore, trafermin is an effective and safe treatment for periodontal regeneration in intrabony defect, and its efficacy was superior in rhFGF-2 compared to EMD treatments.

Risk analysis of failure of root canal treatment for teeth with inaccessible apical constriction.

OBJECTIVE: The risk of failure of root canal therapy was assessed in teeth with inaccessible apical constriction and factors influencing treatment outcome in these teeth were analyzed. METHODS: From the same 57 patients, one tooth with inaccessible apical constriction (n=57) and one tooth with adequate accessibility (n=57) were included in this retrospective investigation. Cox regression analysis was used to analyze factors that may have influenced the outcome one or more years after obturation. These factors included inaccessibility, systemic disease, canal curvature, preoperative periradicular lesion, widening of periodontal ligament space, patient gender and age, size of master apical file, preoperative pulp vitality, years of operator experience and obturation length. RESULTS: Inaccessible apical constriction was a significant factor related to outcome (odds ratio, 5.301). Preoperative presence of periradicular lesion significantly influenced the outcome in cases with inaccessibility (odds ratio, 4.448). CONCLUSION: Inaccessibility increases the risk of root canal therapy failure particularly in teeth with preoperative periradicular lesion.

Combination of Root Surface Modification with BMP-2 and Collagen Hydrogel Scaffold Implantation for Periodontal Healing in Beagle Dogs.

UNLABELLED: Objective : Biomodification of the root surface plays a major role in periodontal wound healing. Root surface modification with bone morphogenetic protein (BMP) stimulates bone and cementum-like tissue formation; however, severe ankylosis is simultaneously observed. Bio-safe collagen hydrogel scaffolds may therefore be useful for supplying periodontal ligament cells and preventing ankylosis. We examined the effects of BMP modification in conjunction with collagen hydrogel scaffold implantation on periodontal wound healing in dogs. MATERIAL AND METHODS: The collagen hydrogel scaffold was composed of type I collagen sponge and collagen hydrogel. One-wall infrabony defects (5 mm in depth, 3 mm in width) were surgically created in six beagle dogs. In the BMP/Col group, BMP-2 was applied to the root surface (loading dose; 1 µg/µl), and the defects were filled with collagen hydrogel scaffold. In the BMP or Col group, BMP-2 coating or scaffold implantation was performed. Histometric parameters were evaluated at 4 weeks after surgery. RESULTS: Single use of BMP stimulated formation of alveolar bone and ankylosis. In contrast, the BMP/Col group frequently enhanced reconstruction of periodontal attachment including cementum-like tissue, periodontal ligament and alveolar bone. The amount of new periodontal ligament in the BMP/Col group was significantly greater when compared to all other groups. In addition, ankylosis was rarely observed in the BMP/Col group. CONCLUSION: The combination method using root surface modification with BMP and collagen hydrogel scaffold implantation facilitated the reestablishment of periodontal attachment. BMP-related ankylosis was suppressed by implantation of collagen hydrogel.