A prospective cohort study of immediate implantation and delayed implantation for a labial bony dehiscence defect in the maxillary aesthetic area / 口腔疾病防治

Objective @# To investigate the effect of immediate and delayed implant placement on dimensional changes in hard and soft tissues as well as esthetic outcomes. @*Methods @# A total of 40 maxillary single anterior teeth with a dehiscence defect on the labial bone (≤4 mm) were categorized into two groups according to the timing of implant placement: immediate implant placement (n = 20) or delayed implant placement (n = 20). Guided bone regeneration (GBR) was conducted at the sites using a flap approach, and the implants were given immediate provisionalization. Implant survival rates, dimensional changes in hard and soft tissues during the six- and twelve-month follow-ups, and pink esthetic scores (PESs) were measured. @*Results @# The implant survival rates in both groups were 100%, and no complications occurred during the follow-up time. There was no significant difference between the two groups at the measurement sites in the dimensional change of hard and soft tissues during the six- and twelve-month follow-ups. The largest resorption was observed at the implant neck, with a loss of (1.29 ± 0.71) mm in the immediate implant placement group and (1.43 ± 0.19) mm in the delayed implant placement group. The mean PES scores were (10.95 ± 1.51) for the immediate implant placement group and (11.05 ± 1.23) for the delayed implant placement group. @*Conclusion@# Immediate implantation or delayed implantation combined with GBR and immediate provisionalization might both be a prospective treatment strategy for a maxillary single anterior tooth with a dehiscence defect on the labial bone.

Periodontal healing using a collagen matrix with periodontal ligament progenitor cells in a dehiscence defect model in beagle dogs

PURPOSE: To histologically characterize periodontal healing at 8 weeks in surgically created dehiscence defects in beagle dogs that received a collagen matrix with periodontal ligament (PDL) progenitor cells. METHODS: The bilateral maxillary premolars and first molars in 6 animals were used. Standardized experimental dehiscence defects were made on the buccal side of 3 premolars, and primary culturing of PDL progenitor cells was performed on the molars. Collagen matrix was used as a scaffold and a delivery system for PDL progenitor cells. The experimental sites were grafted with collagen matrix (COL), PDL progenitor cells with collagen matrix (COL/CELL), or left without any material (CTL). Histologic and histomorphometric analyses were performed after 8 weeks. RESULTS: The defect height from the cementoenamel junction to the most apical point of cementum removal did not significantly differ across the CTL, COL, and COL/CELL groups, at 4.57±0.28, 4.56±0.41, and 4.64±0.27 mm (mean ± standard deviation), respectively; the corresponding values for epithelial adhesion were 1.41±0.51, 0.85±0.29, and 0.30±0.41 mm (P<0.05), the heights of new bone regeneration were 1.32±0.44, 1.65±0.52, and 1.93±0.61 mm (P<0.05), and the cementum regeneration values were 1.15±0.42, 1.81±0.46, and 2.57±0.56 mm (P<0.05). There was significantly more new bone formation in the COL/CELL group than in the CTL group, and new cementum length was also significantly higher in the COL/CELL group. However, there were no significant differences in the width of new cementum among the groups. CONCLUSIONS: PDL progenitor cells carried by a synthetic collagen matrix may enhance periodontal regeneration, including cementum and new bone formation.

Bone Regeneration Using Bilayer Bone Augmentation around Dental Implants: A Preliminary Study by Micro-CT in Dogs

The purpose of this preliminary study was to compare the effects of the bilayer bone augmentation technique (BBA) for the treatment of dehiscence-type defects around implants and evaluate the role as a membrane of the xenogenic bone positioned as the outer layer in the BBA technique using a micro-computed tomography (micro-CT). Four standardized dehiscence defects were prepared on each mandible bilaterally in 3 dogs and 1 implant was placed per defect, where each defect was treated with autograft (AB), xenograft (XB), BBA technique, or negative control without a membrane. Two months post-regenerative surgery, sectioned bone blocks were obtained. The image acquisitions were then scanned by micro-CT. Bone volume (BV), horizontal bone width (HBW) and vertical bone height (VBH) were measured through the analyses program. The BV were 11.08 mm3, 10.42 mm3, 8.1 mm3, and 7.01 mm3 in XB, BBA, control, and AB group in sequence of high value, respectively. HBW were 1.33 mm, 1.3 mm, 1.06 mm, and 1.03 mm in XB, BBA, AB, and control group, respectively. VBH were 4.88 mm, 4.85 mm, 4.74 mm, and 4.67 mm in XB, BBA, AB, and control group, respectively. However, there was no significant difference between the 4 groups. VBH tended to be higher in sequence of control, AB, BBA, and XB group (p for trend <0.05). The results showed the usefulness of the BBA technique involving mechanical support for prolonged space maintenance of xenogenic bone, for the treatment of dehiscence-type defects around implants. However, further studies with a larger sample size are required to confirm the results.

Bone formation following dental implant placement with augmentation materials at dehiscence defects in dogs : pilot study / 대한치주과학회지

PURPOSE: Guided bone regeneration(GBR) has emerged as a treatment in the management of osseous defects associated with dental implants. But several studies have reported different degrees of success of guided bone regeneration, depending upon the type of barrier selected, presence or absence of an underlying graft material, types of graft material, feasibility of technique, and clinician's preference. The aim of the present study was to evaluate bone formation following dental implant placement with augmentation materials at dehiscence defects in dogs. MATERIAL AND METHODS: Standardized buccal dehiscence defects(3x5 mm) were surgically 2 Mongrel dog's mandibles, each 8 SLA surface, 8 anodizing surface implants. Each buccal dehiscence defect received flap surgery only(no treatment, control), Cytoflex(R) membrane only, Resolut XT(R) membrane only, Resolut XT(R)+Osteon(TM). Animals were sacrificed at 8 weeks postsurgery and block sections were harvested for histologic analysis. RESULTS: All experimental group resulted in higher bone formation than control. Resolut XT(R)+Osteon(TM) group resulted appeared highest defect resolution. There was no difference between SLA and anodizing surface, nonresorbable and resorbable membrane. CONCLUSION: GBR results in rapid and clinically relevant bone closure on dehiscence defects of the dental implants.

The Effects of DFDB combined with Dura mater on the Periodontal Wound Healing of Dehiscence Defects in Dogs / 대한치주과학회지

The present study invetigates the effects of root planing only(control group) , DFDBA alone(test group 1) and combined use of DFDB and Dura mater(test group 2) in dehiscence defects in dogs. The results of 8weeks post-surgery by histological comparison between the three groups are as follows. 1. The contol group showed minimum regeneration of new cementum and new bone with limited migration of epitheilal cells, and healed by connective tissue attachment. 2. The test group 1 showed minimum regeneration of new cementum and new bone with limited migration of epitheilal cells, and healed by connective tissue attachment. 3. The test group 2 showed significant amount of the new cementum and new bone. 4. Both control and test groups healed without any observable root resorption and ankylosis. The above the results suggest that the use of resorbable Dura mater only does not improve the regeneration of new bone and periodontal ligament due to difficulties of space making, but the combined use with DFDB may be more effective.

The Effects of Graft of DFDB combined with Calcium Sulfate membrane on the Periodontal Wound Healing of Horizontal Dehiscence Defects in Dogs / 대한치주과학회지

The present study investigates the effects of DFDB graft combined with Calcium sulfate membrane on the periodontal wound healing in dehiscence defects of dogs. Following the initiation of general anesthesia by I.V. administration of 30mg/kg of pentobarbital, first premolar was extracted and full-thickness flap was elevated from the second to the fourth premolar. The portion of premolars coronal to the alveolar crest was removed and mesial and distal roots separated to produce single rooted teeth. Exposed root canals were sealed with Caviton and covered completely with flaps sutured. Following the healing period of 12 weeks, the surgical sites were uncovered and 4x4mm dehiscence defects were surgically created. Those defects with DFDB graft combined with Calcium sulfate membrane following root planing, were designated as test sites and those with flap surgery-only were designated as controls. 1. No foreign-body reaction or inflammation were observed in either groups. Calcium sulfate was completely resorbed in the test sites. 2. Significantly greater amounts of new cementum was observed in test sites compared with the controls. Significant amounts of functionally orientated collagens were observed in the test sites. 3. New bone formation was observed in significantly greater amounts in test sites. The results suggest that combined graft of DFDB and calcium sulfate is extremely biocompatible with a potential for new bone and cementum formation, and functional alignment of periodontal ligaments.