Effects of combined use of recombinant human fibroblast growth factor-2 and ß-tricalcium phosphate on ridge preservation in dehiscence bone defects after tooth extraction: A split-mouth study in dogs.

BACKGROUND AND OBJECTIVE: Following tooth extraction, bone resorption is especially severe in cases complicated with buccal dehiscence bone defects. To minimize this, various bone graft materials have been used for alveolar ridge preservation. This study aimed to evaluate additional effects of the concomitant use of recombinant human fibroblast growth factor-2 (rhFGF-2) with ß-tricalcium phosphate (ß-TCP) on ridge preservation in a dehiscence defect model after tooth extraction in dogs. MATERIALS AND METHODS: The maxillary first premolars of six beagle dogs were extracted and dehiscence defects of 4 × 4 × 5 mm (mesio-distal width × bucco-palatal width × depth) were created. Bilateral defects were filled with ß-TCP combined with 0.3% (w/v) rhFGF-2 (test sites) or the scaffold alone (control sites). Twelve weeks post-surgery, histologic and histometric evaluations were performed. RESULTS: Morphological measurements using micro-computed tomography revealed a significantly greater bone volume at the test sites (48.9 ± 9.06 mm3 ) than at the control sites (38.8 ± 7.24 mm3 ). Horizontal widths of the alveolar ridge at the coronal and middle position at the test sites (2.18 ± 0.71 mm, 2.93 ± 0.53 mm) were significantly greater than those at the control sites (1.47 ± 0.41 mm, 2.36 ± 0.45 mm, respectively). Regarding the histological parameters, the occupation rate of mineralized bone in the original defects was slightly higher at the test sites (44.07 ± 10.19%) than that at the control site (41.15 ± 6.56%). CONCLUSIONS: These results indicate that the adjunct use of rhFGF-2 with ß-TCP is effective for alveolar ridge preservation in fresh extraction sockets with dehiscence defects.

Clinical comparison of an electric-powered ionic toothbrush and a manual toothbrush in plaque reduction: A randomized clinical trial.

OBJECTIVES: This study aimed to evaluate the plaque removal efficacy of a newly developed electric-powered ionic toothbrush vs. a manual toothbrush. MATERIALS AND METHODS: Manual or electric-powered ionic toothbrushes were randomly assigned to 30 healthy volunteers divided into two groups (Phase I). After 2 min of brushing, all tooth surfaces were stained with a plaque staining solution, and blinded examiners performed scoring using the Rustogi Modification of the Navy Plaque Index. Plaque removal rate was calculated at the central incisors, first premolar and first molar, as representative teeth, in the maxilla and mandibula. One week following Phase I, the same examinations were repeated in all subjects using another toothbrush (Phase II), as a crossover design. RESULTS: Electric ionic toothbrushes demonstrated a significantly higher plaque removal rate than manual toothbrushes in the premolar and molar areas (p < .05). However, in the central incisor area, no statistically significant difference was observed. CONCLUSIONS: Compared with manual toothbrushes, electric-powered ionic ones were significantly efficient in removing plaque in the premolar and molar areas.

Ridge reconstruction in damaged extraction sockets using tunnel ß-tricalcium phosphate blocks: A 6-month histological study in beagle dogs.

OBJECTIVE: The present study aimed to evaluate the histological outcome of tunnel ß-TCP blocks grafting in extraction sockets missing the buccal bone wall, after 6 months of healing. BACKGROUND: Tunnel ß-tricalcium phosphate (ß-TCP) blocks made of randomly organized tunnel-shaped ß-TCP ceramics appeared promising for alveolar ridge preservation in tooth extraction sockets missing the buccal bone, in a previous study in dogs, with a 2-month healing time. METHODS: In six beagle dogs, the maxillary first premolars were extracted and the buccal bone was surgically removed to create bone defects of 4 mm (mesio-distal) × 5 mm (apico-coronal) × 4 mm (bucco-palatal). Thus, extraction sockets missing the buccal bone plate were grated with tunnel ß-TCP blocks (test) or left empty for spontaneous healing (control). Histology/histomorphometry was performed after 6 months of healing. RESULTS: The horizontal bucco-palatal width of the alveolar ridge was significantly greater at test sites than at control sites. The amount of mineralized tissue was greater at test sites (57.8% ± 11.1%) than at control sites (28.9% ± 8.5%), while the amount of connective tissue was significantly greater at control sites (41.7% ± 6.4%) than at test sites (19.6% ± 9.2%). No significant difference was found between sites in terms of basic multicellular units and bone marrow. Residual ß-TCP at test sites was 5.8% ± 3.2%. CONCLUSION: Grafting with tunnel ß-TCP block significantly limited the resorption of the alveolar ridge at extraction sockets missing the buccal bone compared with sites left to heal spontaneously, even after 6-month follow-up.

Comparison between different isoelectric points of biodegradable gelatin sponges incorporating ß-tricalcium phosphate and recombinant human fibroblast growth factor-2 for ridge augmentation: A preclinical study of saddle-type defects in dogs.

BACKGROUND AND OBJECTIVE: It is well known that recombinant human fibroblast growth factor-2 (rhFGF-2) signaling plays an important role in tissue repair and regeneration. rhFGF-2 strongly binds to acidic gelatin via ionic linkages and is gradually released upon gelatin decomposition. On the other hand, the linkage between rhFGF-2 and basic gelatin is so weak that most rhFGF-2 is rapidly released from basic gelatin by simple desorption. Gelatin/ß-tricalcium phosphate (ß-TCP) sponges, which comprise 50 wt% gelatin and 50 wt% ß-TCP in a cross-linked structure, can release rhFGF-2 gradually owing to their electrical features. In a previous study, we reported that new bone height in the test group using rhFGF-2 with acidic gelatin/ß-TCP sponges was significantly greater than that in the control group using acidic gelatin/ß-TCP sponges alone in a ridge augmentation model in dogs. However, whether these results depend on controlled release by the gelatin/ß-TCP sponges remains controversial. In this study, we evaluated the effects of controlled release by comparing acidic and basic gelatin/ß-TCP sponges with different isoelectric points (IEP) on ridge augmentation in dogs. MATERIALS AND METHODS: Twelve weeks after extraction of the maxillary second and third incisors of six dogs, critically sized saddle-type defects (8 mm length × 4 mm depth) were surgically created bilaterally 2 mm from the mesial side of the canine. Acidic gelatin/ß-TCP sponges (IEP 5.0) soaked with 0.3% rhFGF-2 were applied to the defect in the acidic group, whereas basic gelatin/ß-TCP sponges (IEP 9.0) soaked with 0.3% rhFGF-2 were applied to the defect in the basic group. Twelve weeks after surgery, biopsy specimens were obtained and subjected to microcomputed tomography (micro-CT) and histological analyses. RESULTS: New bone area detected by micro-CT analysis was significantly smaller in the basic group than in the acidic group. New bone height calculated by histologic sections was significantly lower in the basic group than in the acidic group. The total tissue height was lower in the basic group than in the acidic group. However, the differences between both sites were not significant. CONCLUSIONS: These findings suggest that in ridge augmentation of saddle-type defects, controlled release of rhFGF-2 induces notably more alveolar bone formation than does short-term application of rhFGF-2.

Biological responses following one-stage full-mouth scaling and root planing with and without azithromycin: Multicenter randomized trial.

BACKGROUND AND OBJECTIVE: Full-mouth scaling and root planing (FM-SRP) increases the systemic levels of inflammatory mediators via early inflammation but may be inhibited using an antimicrobial agent. This prospective intervention study evaluates the biological response and clinical effects of FM-SRP with and without systemically administered azithromycin (AZM). MATERIALS AND METHODS: A multicenter parallel randomized controlled and open-label trial. A central randomization center used computer-generated tables to allocate treatments. Sixty-three patients with moderate to severe generalized periodontitis (New American Academy of Periodontology Classification: Stage3 or 4, Grade B) were randomly assigned to receive FM-SRP with AZM (test group, n = 32) or FM-SRP without AZM (control group, n = 31). Clinical parameters and body temperature were measured, and subgingival plaque, peripheral blood, and gingival crevicular fluid were collected before and after treatment. Periodontopathic bacteria and IgG titers were measured by gingival crevicular fluid and peripheral blood. High-sensitivity assays were used to analyze systemic and local inflammatory markers, such as endotoxin, high-sensitive CRP (hs-CRP), and six inflammatory cytokines. Follow-up 6 weeks. RESULTS: The total number of bacteria and the number of Porphyromonas gingivalis and Prevotella intermedia were significantly lower in the test group after FM-SRP. IgG titers for P gingivalis significantly decreased after FM-SRP with AZM, and the body temperature increased significantly after FM-SRP without AZM. In the control group, serum hs-CRP, IFN-γ, IL-12p70, and IL-6 were significantly increased one day after treatment, but subsequently decreased below the original numerical value. In the test group, only hs-CRP showed a significant increase. CONCLUSIONS: FM-SRP resulted in similar improvements in clinical parameters with and without the use of AZM. Inflammatory mediators showed no difference between the two groups after FM-SRP treatment. The use of AZM was effective in preventing the elevation of body temperature after FM-SRP.

Enamel matrix derivative in liquid form as adjunct to natural bovine bone grafting at buccal bone dehiscence defects at implant sites: An experimental study in beagle dogs.

OBJECTIVES: To evaluate the effect of enamel matrix derivative in liquid form (EMD-liquid) as adjunct to grafting with natural bovine bone (NBB), on new bone formation and osseointegration in buccal dehiscence defects at dental implants. MATERIAL AND METHODS: In six beagles, 3 months after extraction of the mandibular premolars and first molars. Three titanium implants (3.3 Ø × 8.0 mm) were inserted, and dehiscence-type defects (mesiodistal width 3 mm × 5 mm depth) were created on their buccal aspect. The defects were randomly assigned to one of the following three treatment groups: Group 1: NBB, Group 2: NBB/EMD-L, Group 3: Control. All sites were covered with a collagen membrane. Histomorphometric measurements were performed after 3 months of healing. RESULTS: New bone area, bone-to-implant contact (BIC), and first BIC (fBIC) in the NBB and NBB/EMD-L groups were significantly greater than in the control group (p < .05). Further, f-BIC was at a significantly more coronal position in the NBB + EMD-liquid group (0.4 ± 0.1 mm) compared with the NBB group (1.2 ± 0.2 mm). CONCLUSIONS: Natural bovine bone grafting enhances bone regeneration and osseointegration at implants with buccal bone dehiscences compared with no grafting, and adjunct use of EMD-liquid appears to further enhance bone formation and osseointegration.

Histological healing after nonsurgical periodontal treatment with enamel matrix derivatives in canine experimental periodontitis.

The histological outcomes after nonsurgical periodontal treatment with enamel matrix derivatives (EMD) remain controversial. The present study evaluated periodontal wound healing after scaling and root planing (SRP) with subgingival application of EMD for treatment of experimental periodontitis. Periodontal breakdown was induced by applying silk ligatures around mandibular third and fourth premolars of six beagle dogs until radiographic bone loss progressed to approximately half of the root length. Probing pocket depth (PPD) and clinical attachment level (CAL) were proximally measured 2 weeks after ligature removal (baseline). Mesial and distal surfaces of the experimental teeth were subjected to SRP and randomized using a split-mouth design to subgingival application of EMD (test) or normal saline (control). PPD and CAL were re-evaluated at 11 weeks. Animals were sacrificed at 12 weeks for histological analyses. No significant differences were observed in PPD and CAL between both groups at baseline and at 11 weeks. Histologically, test sites exhibited a greater amount of new cementum than that did the control sites (p < 0.01). Moreover, the control sites revealed increased epithelial downgrowth compared with the test sites: (p < 0.05). On the other hand, no intergroup differences were detected in terms of bone position, connective tissue attachment, gingival recession, and planed root length. This study suggested that EMD has an increased potential to support formation of new cementum with decreased epithelial downgrowth when used as an adjunct to nonsurgical periodontal treatment.

Er:YAG laser-assisted comprehensive periodontal pocket therapy for residual periodontal pocket treatment: A randomized controlled clinical trial.

BACKGROUND: This study evaluated the effectiveness of a novel pocket therapy (Er:YAG laser-assisted comprehensive periodontal pocket therapy [Er-LCPT]) for residual pocket treatment, compared with conventional mechanical treatment alone, in a randomized controlled clinical trial. METHODS: Two sites in 18 patients having residual periodontal pockets of ≥5 mm depth, extant following initial active therapy, or during supportive therapy, were randomized into two groups in a split mouth design: the control group received scaling and root planing (SRP) by curette, and the test group received Er-LCPT using curette and laser. With Er-LCPT, after root debridement, inflamed connective tissue on the inner gingival surface and on the bone surface/within extant bone defects was thoroughly debrided. Furthermore, removal of proximate oral epithelium and coagulation of the blood clot in the pocket entrance were performed with laser. Clinical parameters were evaluated, before and after treatment, through 12 months. RESULTS: Both groups showed significant improvements in clinical parameters. With Er-LCPT, pocket debridement was thoroughly and safely performed, without any adverse side effects and complications, and favorable healing was observed in most of the cases. At 12 months, Er-LCPT demonstrated significantly higher probing pocket depth reduction (2.78 mm vs. 1.89 mm on average; p = 0.012, Wilcoxon signed-rank test), clinical attachment gain (1.67 mm vs. 1.06 mm; p = 0.004) as primary outcomes, and reduced BOP value (0.89 vs. 0.56; p = 0.031), compared with SRP alone. CONCLUSION: The results of this study indicate that Er-LCPT is more effective for residual pocket treatment, compared with SRP alone.

Influence of the bone graft materials used for guided bone regeneration on subsequent peri-implant inflammation: an experimental ligature-induced peri-implantitis model in Beagle dogs.

PURPOSE: We aimed to histologically evaluate the influence of bone materials used during guided bone regeneration (GBR) on subsequent peri-implantitis in an experimental ligature-induced peri-implantitis model in beagle dogs. METHODS: Bilateral mandibular premolars (PM2-4) were extracted from six beagle dogs. After 3 months, standardized bone defects (3 mm [mesio-distal width] × 2 mm [bucco-lingual width] × 3 mm [depth]) were created in the experimental group, with simultaneous dental implant placement at the center of the defects. The defects were randomly filled with either autograft (AG) or deproteinized bovine bone mineral (DBBM) and covered with a collagen membrane. In the control group, implant fixtures were placed without creating an intrabony defect. After 3 months, a healing abutment was placed. Four weeks later, a 3-0 silk thread was ligated around the implants to induce peri-implantitis. After 4 weeks, the specimens were dissected and histologically examined. RESULTS: There were no clinical findings of inflammation until silk thread ligation. Four weeks after the onset of peri-implantitis, gingival redness and swelling were seen with mild resorption of the peri-implant bone on dental radiographs. There were no significant differences between the AG, DBBM, and control groups for the following parameters: bone-to-implant contact, distance from the implant shoulder to the base of the bone defect, area of bone defect, and area of new bone. CONCLUSIONS: Within the limitations of this study, it can be concluded that peri-implant tissues after GBR using AG and DBBM underwent the same degree of bone resorption by peri-implantitis as the no defect group.

Enhanced new bone formation in canine maxilla by a graft of electrically polarized ß-tricalcium phosphate.

We succeeded in the electrical polarization of ß-tricalcium phosphate (ß-TCP) granules and performed an unprecedented attempt to implant them into maxillary bone defects in canines to confirm their ability to facilitate new bone formation. Two holes were drilled into each maxilla half of a canine and filled with electrically polarized and nonpolarized ß-TCP granules (grouping assignment was decided randomly). The implanted specimens were dissected en bloc and used for microcomputed tomography (µCT) observations and histological analyses 4 and 8 weeks after the operation. New bone ingrowth in the bone hole progressed over time from the superficial layer of the cortex toward the inner cancellous bone. The percentage area of new bone in the bone hole, as measured by µCT in the sagittal plane, was significantly larger after 4 and 8 weeks, and that measured by H&E-stained specimens in the transverse plane after 4 weeks was significantly larger in the polarized group than in the nonpolarized group. In addition to the structural stability and chemical characteristics of the ß-TCP granules, electrical stimulation bears influence not indirectly but directly on osteogenic and vessel cells, which might work cooperatively for the early initiation of the bone formation process.

Ridge preservation of extraction sockets with buccal bone deficiency using poly lactide-co-glycolide coated ß-tricalcium phosphate bone grafts: An experimental study in dogs.

BACKGROUND: The alveolar ridge undergoes pronounced reduction in height and width following tooth extraction. This study aims to comparatively evaluate the potential for ridge preservation in extraction sockets with buccal bone deficiency of ß-tricalcium phosphate coated with poly lactide-co-glycolide (ß-TCP/PLGA) and conventional particulate ß-TCP. METHODS: In six beagles, maxillary first premolars were extracted after removal of their buccal bone plates. Standardized bone defects (4 [mesiodistal width] × 4 [buccopalatal width] × 5 [depth] mm) were created at the sites of extraction sockets and filled with ß-TCP/PLGA (test sites) or particulate ß-TCP (control sites). Microcomputed tomography, histologic, and histometric evaluations were performed 12 weeks post-surgery. RESULTS: The test sites exhibited a significantly greater bone volume than the control sites (25.7 ± 2.14 versus 16.0 ± 3.3 mm3 ), although no statistically significant difference was detected in bone material density (746.3 ± 23.9 versus 714.5 ± 37.0 g/cm3 , respectively). Relative to the control sites, the test sites exhibited significantly greater alveolar-ridge coronal (2.0 ± 0.4 versus 1.1 ± 0.3 mm) and middle (2.9 ± 0.2 versus 2.1 ± 0.3 mm) horizontal widths and proportions of woven bone (50.3 ± 8.1% versus 38.0 ± 5.2%) and bone marrow (17.7 ± 6.6% versus 9.7 ± 4.1%) but a significantly lower proportion of connective tissue (10.7 ± 4.5% versus 18.3 ± 5.7%). CONCLUSION: Within the limitations of this study, the moldable ß-TCP/PLGA graft appears to exhibit a greater potential than the conventional particulate ß-TCP graft for ridge preservation of extraction sockets with buccal bone deficiency.

In vitro and clinical evaluation of optical coherence tomography for the detection of subgingival calculus and root cementum.

This study evaluated the effectiveness of swept-source optical coherence tomography (ss-OCT) for detecting calculus and root cementum during periodontal therapy. Optical coherence tomography (OCT) images were taken before and after removal of subgingival calculus from extracted teeth and compared with non-decalcified histological sections. Porcine gingival sheets of various thicknesses were applied to the root surfaces of extracted teeth with calculus and OCT images were taken. OCT images were also taken before and after scaling and root planing (SRP) in human patients. In vitro, calculus was clearly detected as a white-gray amorphous structure on the root surface, which disappeared after removal. Cementum was identified as a thin, dark-gray layer. The calculus could not be clearly observed when soft tissues were present on the root surface. Clinically, supragingival calculus and cementum could be detected clearly with OCT, and subgingival calculus in the buccal cervical area of the anterior and premolar teeth was identified, which disappeared after SRP. Digital processing of the original OCT images was useful for clarifying the calculus. In conclusion, ss-OCT showed potential as a periodontal diagnostic tool for detecting cementum and subgingival calculus, although the practical applications of subgingival imaging remain limited.

Ridge Preservation After Tooth Extraction With Buccal Bone Plate Deficiency Using Tunnel Structured ß-Tricalcium Phosphate Blocks: A 2-Month Histologic Pilot Study in Beagle Dogs.

BACKGROUND: Reduction in alveolar ridge volume is a direct consequence of tooth extraction. Tunnel ß-tricalcium phosphate (ß-TCP) blocks were manufactured from randomly organized tunnel-shaped ß-TCP ceramic. Efficacy of these blocks compared to extraction alone for alveolar ridge preservation after tooth extraction with buccal bone deficiency was evaluated. METHODS: Maxillary first premolars of six beagle dogs were extracted after removing the buccal bone, and bone defects of 4 × 4 × 5 mm (mesio-distal width × bucco-palatal width × depth) were created. Fresh extraction sockets with buccal bone defects were filled with tunnel ß-TCP blocks at test sites. Two months after the operation, histologic and histometric evaluations were performed. RESULTS: Regarding histologic sections, coronal and middle horizontal widths of the alveolar ridge were significantly greater at test sites (3.2 ± 0.5 and 3.6 ± 0.4 mm, respectively) than at control sites (1.2 ± 0.3 and 2.0 ± 0.6 mm, respectively). The amount of woven bone was significantly greater at test sites (62.4% ± 7.9%) than at control sites (26.8% ± 5.3%), although that of connective tissue and bone marrow was significantly greater at control sites (38.1% ± 6.2% and 16.0% ± 6.9%, respectively) than at test sites (10.7% ± 5.7% and 4.1% ± 2.2%, respectively). Regarding basic multicellular units, no statistically significant difference was found between the test and control sites (0.5% ± 0.1% and 0.6% ± 0.1%, respectively). CONCLUSION: Tunnel ß-TCP blocks represent an effective bone-graft material for alveolar ridge preservation in fresh extraction sockets with buccal bone defects.

Reproducibility of probing depth measurement by an experimental periodontal probe incorporating optical fiber sensor.

BACKGROUND: An experimental periodontal sensor probe (SP) equipped with an optical fiber for recording function was developed. The aim was to test the intraexaminer reproducibility of probing using the SP and to assess the consistency with the manual probe (MP). METHODS: The SP was assembled with an external sheath covering the probe tip of an MP. The sheath was slid backward by the free gingival margin while probing and the sliding distance was detected by the sensor. The probing was conducted with the walking stroke at six sites for four first molar teeth in six maintenance patients with the SP and the MP at a 1-hour interval. The deepest reading in the vicinity of each site was recorded. The measurements were rerecorded 1 week later. RESULTS: The mean depth was 3.03 and 3.08 mm recorded by the MP and SP, respectively. Although no significant difference was found between the probes (P >0.05) in all measurement sites, the mean depth at the lingual site of the upper left first molar was noticeably lower with the SP. For sites ≥7 mm, significantly lower depth was recorded by the SP (P <0.05). Zero discrepancy in duplicate measurements was found in 76% of all sites with MP and 92% with SP. CONCLUSIONS: The reproducibility of the SP was comparable to that of the MP. The results indicate that for sites of maintenance patients with probing depth <7 mm there was excellent agreement obtained by a single examiner using the SP compared to the MP.

Application of periodontal ligament cell sheet for periodontal regeneration: a pilot study in beagle dogs.

OBJECTIVE: The ultimate goal of periodontal treatment is to regenerate the damaged periodontal support. Although periodontal ligament (PDL) cells are essential for periodontal regeneration, few studies have reported the transplantation of periodontal ligament cells to periodontal defects. We developed a new method to apply periodontal ligament cells as a sheet to the defect. The aim of this study was to investigate the periodontal healing after application of the periodontal ligament cell sheet in beagle dogs. METHODS: Autologous periodontal ligament cells were obtained from extracted premolars of each beagle dog. Periodontal ligament cell sheets were fabricated using a temperature-responsive cell culture dish. Dehiscence defects were surgically created on the buccal surface of the mesial roots of bilateral mandibular first molars of each dog. In the experimental group (five defects), periodontal ligament cell sheet with reinforced hyaluronic acid carrier was applied to the defect. Only the hyaluronic acid carrier was applied to the contralateral side as a control (five defects). Eight weeks after surgery, the animals were sacrificed and decalcified specimens were prepared. Healing of the periodontal defects was evaluated histologically and histometrically. RESULTS: No clinical signs of inflammation or recession of gingiva were observed in both experimental and control groups. In the experimental group, periodontal tissue healing with bone, periodontal ligament and cementum formation was observed in three out of five defects. In the control group, such periodontal tissue formation was not observed except in one defect. Histometric analysis revealed that the formation of new cementum in the experimental group was significantly higher than that in the control group. CONCLUSION: The periodontal ligament cell sheet has a potential to regenerate periodontal tissue and may become a novel regenerative therapy.