Pedicle Periosteum as a Barrier for Guided Bone Regeneration in the Rabbit Frontal Bone.

BACKGROUND/AIM: For alveolar ridge reconstruction prior to dental implant placement, a barrier membrane is placed to create space over the bone defect. Although periosteum possesses osteogenic capacity, direct contact between defects and periosteum has been avoided. The present study aimed to investigate whether pedicle periosteum could be used as a barrier membrane. MATERIALS AND METHODS: Twelve rabbits were used. A U-shaped incision was made in the frontal bone, and the skin-periosteum over the frontal bone was stripped. Two trephine-drilled holes with a diameter of 5 mm were prepared in the frontal bone. One hole was covered with pedicle periosteum (periosteum side), and the periosteum was secured to the contralateral side. The other defect was covered with an occlusive membrane (membrane side). RESULTS: The histological observation showed that both defects, which were covered either by the periosteum or by the membrane, were closed almost completely after 12 weeks of healing. No statistically significant difference was observed in the bone defect closure rates between the two sides at 4 and 12 weeks. CONCLUSION: This study demonstrated that the pedicle periosteum possesses regenerative effects equivalent to those of occlusive membrane. The periosteum contributes to new bone formation by acting as a mechanical barrier and a source of osteogenic components.

Micro-CT observation of angiogenesis in bone regeneration.

OBJECTIVES: Restoration of an adequate blood supply is essential for the bone healing process and is key to the success of bone augmentation procedures. In this study, we evaluated angiogenesis in rat calvarial flat bone defects using in vivo microfocus computed tomography (micro-CT). MATERIALS AND METHODS: Twenty rats were used. The calvarium was exposed and calvarial bone defects of critical (5-mm diameter) and non-critical (2.7-mm diameter) sizes were prepared. Bone regeneration and angiogenesis were evaluated by image analysis using micro-CT and histological examination. RESULTS: Critical- and non-critical-sized calvarial bone defects showed bone regeneration and angiogenesis around the midsagittal suture. Critical-sized calvarial bone defects showed approximately 1.2% reossification of the original surgical defect, whereas the non-critical-sized defects showed approximately 43.3% reossification at day 28. Furthermore, angiogenesis was observed later in the critical-sized calvarial bone defects (about 38.2%), whereas angiogenesis was observed early in the non-critical-sized calvarial bone defects (about 75.5%) at day 28. New blood vessel networks were observed around defects of both sizes. CONCLUSIONS: Angiogenesis preceded bone regeneration around critical- and non-critical-sized calvarial bone defects. Angiogenesis led to full bone formation in non-critical-sized defects.

Treatment of titanium dental implants with three piezoelectric ultrasonic scalers: an in vivo study.

BACKGROUND: Dental implants require regular maintenance. It is crucial that the instrument used for maintenance be able to remove plaque and calculus from the implant surface effectively and efficiently, while causing minimal damage to its circumference. Some ultrasonic scalers may be useful for implant maintenance; however, no clinical study has examined this. This study evaluated the treatment of titanium implants with three piezoelectric scalers in vivo. METHODS: Fourteen patients underwent implant treatment in which plaque and calculus were removed from the abutment surfaces with ultrasonic scalers. The abutments were treated with scalers with carbon (VS; N = 7), plastic (PS; N = 7), or metallic (ES; N = 7) tips. The abutment surface characteristics were examined after instrumentation using scanning electron microscopy. The amount of plaque remaining and roughness were estimated using a modification of the remaining plaque and calculus score and the modified roughness score, respectively. In addition, the abutment surfaces were imaged with a laser profilometer and a laser scanning electron microscope (SEM). RESULTS: The remaining plaque and calculus scores did not differ significantly among the VS, PS, and ES groups. VS and PS produced a significantly smoother abutment surface than ES. The laser SEM three-dimensional images also demonstrated that VS and PS produced smooth abutment surfaces, whereas ES resulted in damaged surfaces. CONCLUSIONS: VS and PS produced clean, smooth abutment surfaces. Piezoelectric scalers with non-metal tips are suitable for use in dental implant maintenance.

The use of porous beta-tricalcium phosphate blocks with platelet-rich plasma as an onlay bone graft biomaterial.

BACKGROUND: An experimental study of rabbit calvaria evaluated the suitability of porous beta-tricalcium phosphate (beta-TCP) block as a biomaterial for onlay bone grafting and determined whether the addition of platelet-rich plasma (PRP) can accelerate bone formation inside the pores of the beta-TCP block. METHODS: In eight rabbits, the calvarium was exposed, and the marrow was penetrated. The beta-TCP blocks were made of Ca3(CO4)3 (porosity, 75%; diameter, 8 mm; thickness, 5 mm). For the experimental group, the blocks were treated with PRP; for the control group, the blocks were treated with venous blood only. Each block was placed in the bone, attached with a titanium screw, and covered with a cutaneous flap. The animals were sacrificed after 3 months, and the tissue ingrowth into the blocks was euthanized. RESULTS: Histologic and histomorphometric measurements demonstrated that there was no inflammatory infiltration around the blocks in either group. New bone formation inside the blocks originated from the parent bone in both groups. The mineralized bone generated tended to climb along the inner walls of the block. In addition, mineralized bone formation was noted around the titanium screw. Furthermore, there was no significant difference between the experimental and control groups in the relative amounts of newly generated tissue and mineralized bone generated in the blocks. CONCLUSION: Porous beta-TCP block is a promising biomaterial for clinical situations requiring bone augmentation; however, the addition of PRP did not induce significantly more new bone formation.

Periodic exacerbation of gingival inflammation during the menstrual cycle.

Sex hormones are believed to be a risk factor for periodontitis because of their ability to proliferate specific periodontal microorganisms and affect host immunologic response. In this case report, gingival redness and swelling occurred during the menstrual cycle, although the patient maintained good oral hygiene during periodontal treatment. Medical history revealed that exacerbation of gingival inflammation corresponded to the menstrual cycle and occurred during the ovulation period, when estrogen levels are high. Mean bleeding index of the ovulation period (18.9%) showed higher levels than that during the menstrual phase (5.3%). This case indicates that frequent and effective maintenance should be provided while considering the influence of the menstrual cycle, as sex hormones may be involved in exacerbating gingival inflammation.

The comparative effect of ultrasonic scalers on titanium surfaces: an in vitro study.

BACKGROUND: Professional maintenance is as important for patients with dental implants as it is for patients with natural teeth. However, no proper maintenance instruments have been available for implant patients. The purpose of this in vitro study was to compare the effects of a new ultrasonic scaler (VR), a conventional ultrasonic scaler (SP), and a plastic scaler (PS) on titanium surfaces. METHODS: To simulate subgingival conditions, the implant healing abutments were connected to acrylic resin blocks with artificial gingiva using silicon impression material. The abutments were painted with ink as an artificial form of debris. The ink was removed with the VR, SP, or PS scaler for 60 seconds under standardized conditions, and the removal rate was calculated. The roughness of the abutment surface was measured with a profilometer and observed by scanning electron microscopy (SEM). RESULTS: The removal rate using the VR and SP scalers was higher than that using the PS scaler. No significant differences in the surface roughness or SEM observations were found among the VR, SP, or PS scalers. CONCLUSIONS: In this preliminary study, the new ultrasonic scaler and conventional ultrasonic scaler were shown to be useful for removing artificial debris and produced no significant damage to titanium surfaces compared to plastic scalers. We concluded that new and conventional ultrasonic scalers with a non-metal tip would be suitable for implant maintenance.

Comparison of the effects of various periodontal rotary instruments on surface characteristics of root surface.

The efficacy of scaling and root planing using various periodontal rotary instruments was examined. Eighty extracted human teeth with a history of periodontal disease were divided into four groups of 20 and subjected to one of the following procedures: Use of 1) a Root Burnisher, 2) a Perio Planing Bur (both rotating instruments for contra angle handpieces), 3) a Tooth Planing Bur (rotating instrument for use with an air turbine), or 4) a Gracey Scaler. In each case, the time required for cleaning was measured. Twenty healthy extracted human teeth were used as untreated controls. After treatment, the surface roughness of 10 specimens out of each group were measured using a profilometer and observed by scanning electron microscopy (SEM). Half of the samples were then incubated in dishes with a suspension of fibroblasts. After counting the number of attached cells, the attachment of fibroblasts was observed by SEM. The root surfaces treated with the rotary instruments appeared smooth and there were no significant differences between groups. From the SEM observations, smooth root surfaces with different surface textures were evident and a tight attachment of fibroblasts was observed. The results of this study suggest that use of rotary instruments is superior for periodontal scaling and root planing.

Effects of a new ultrasonic scaler on fibroblast attachment to root surfaces: a scanning electron microscopy analysis.

OBJECTIVE: A study was conducted to examine the effectiveness of scaling and root planing using a new ultrasonic scaler (Vector). METHODS: Eighty extracted teeth affected by periodontal disease were sorted into four groups of 20, each of which was subjected to one the following procedures: use of the Vector, Vector with polish, Enac and a Gracey scaler. The time spent on cleaning was measured. Half of the sample teeth were examined at random for surface roughness, and the surface texture was evaluated by means of the Remaining Calculus Index (RCI) and the Roughness and Loss of Tooth Substance Index (RLTSI). The remaining samples were incubated in dishes with a suspension of fibroblasts. After measuring the number of attached cells, the attachment of fibroblasts was observed by scanning electron microscopy. RESULTS: The RLTSI values in the Vector and Vector with polish groups were significantly lower than those in the Enac and Gracey groups, whereas the number of attached cells in the Vector with polish group was larger than in the Enac group. Cell attachment in the Vector and Vector with polish groups proved to be better than in the Enac and Gracey groups. CONCLUSION: Since use of the Vector with polish was able to provide scaling and root planing with minimal damage and tight attachment of fibroblasts, it is suggested that this may be a useful instrument for scaling and root planing.

Effects of ipriflavone on bone augmentation within a titanium cap in rabbit calvaria.

Ipriflavone (7-isopropoxyisoflavone, IP), a drug used in the treatment of osteoporosis, may promote bone formation during bone remodeling. IP has been shown to accelerate both the activity of, and formation of mineralized nodules by a human osteosarcoma cell line at an early stage. However, the direct effects of IP on bone augmentation have not been investigated. The purpose of this study was to determine whether IP induces bone augmentation within a titanium cap in rabbit calvaria at an early stage. Five adult male Japanese white rabbits were used. One cap (test site) was packed with IP in a collagen gel, and the other (control site) was packed with the collagen gel alone. After the one- and three-month healing periods, we measured the newly generated tissue and bone within the titanium caps. The amount of newly generated tissue within the titanium caps of the control sites was higher than the tests sites after one month and three months. However, the percentage of newly generated bone/bone marrow in the newly generated tissue at the test sites was higher than for the control sites after one month and three months. These results suggest that IP affects the quality of bone augmentation at an early stage.