Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tooth Socket”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

1,358 records · Page 76Linked to original sources
PubMedDate not supplied

Implants placed in immediate extraction sites: a report of histologic and histometric analyses of human biopsies.

Five titanium plasma-sprayed implants were biopsied from a human volunteer 6 months after placement. Four test implants had been placed in immediate extraction sockets, while one implant was placed in a mature site and served as a control. The histologic analysis demonstrated that all five implants achieved osseointegration as demonstrated by light microscopy, whereas a varying degree of bone-implant contact was observed. The non-loaded control implant had the highest percentage of bone-implant contact, 72%, followed by the two implants placed in the canine sites presenting with a horizontal defect dimension of 1.5 nm or less. These implants were placed without a barrier membrane, but in a submerged fashion. The histometric analysis showed a mean bone-implant contact of 50% for these two implants. The lowest mean bone-implant contact (17%) was observed for the two molar implants, which had horizontal defect dimensions of 4 mm; these implants were placed in a non-submerged fashion with the implants perforating an expanded polytetrafluoroethylene membrane. The authors concluded that osseointegration may occur in immediate extraction sites in humans using titanium implants with a plasma-sprayed surface. The horizontal component of the peri-implant defect was apparently the most critical factor relating to the final amount of bone-implant contact.

Alveolar Process↗
PubMedDate not supplied

The use of e-PTFE barrier membranes for bone promotion around titanium implants placed into extraction sockets: a prospective multicenter study.

This multicenter study was conducted to determine the predictability for implants placed into immediate extraction sockets and augmented with e-PTFE barrier membranes. Forty-nine implants were placed in immediate extraction sockets. Initial and final defect measurements and the number of threads exposed were compared. Patients were followed up to 1 year after implant loading. Three implants were lost at the abutment connection surgery. The 1-year survival rate was 93.9%. Twenty barrier membranes became exposed and were removed prior to stage 2 surgery, while the remaining barriers were removed at abutment connection. The average defect bone formation for membrane-retained sites was 4.8 mm, while the average bone formation for sites in which the membranes were prematurely removed was 4.0 mm (P < .0001). At stage 2 surgery there was an average of 0.6 threads exposed (P < .001) for the membrane-retained sites and 2.6 threads for the early removal sites (NS). Forty-five pairs of nonstandardized radiographs were evaluated for bone loss after implant loading (average 7.5 months). The mesiodistal bone loss averaged 0.72 mm. Within the limits of this study, e-PTFE membranes will promote clinically and statistically significant amounts of bone around immediately placed implants. Retention of e-PTFE barriers until stage 2 surgery improves the amount of bone promoted around the implants.

Adult↗
PubMed1993

The role of early versus late removal of GTAM membranes on bone formation at oral implants placed into immediate extraction sockets. An experimental study in dogs.

The purpose of this study was to compare the effect of early versus late removal of expanded polytetrafluoroethylene (e-PTFE) membranes on bone formation at oral implants. Thirty Brånemark fixtures were placed into immediate extraction sockets with buccal bone dehiscences augmented by e-PTFE membranes. At 4 weeks, the membranes and underlying soft tissues were removed from 5 implants, but at 16 sites only the membranes were extirpated. In 9 sites, the membranes remained in place during the healing period. Sixteen weeks after fixture insertion, the sites in which the membrane was retained (MRET) showed an average of 5.2 mm of clinical bone height increase (100% of bone fill). For sites where the membrane together with underlying soft tissues were removed (MRB), the corresponding value was 2.0 mm (42% of bone fill). Implants at which only the membrane was removed (MR) showed the least clinical bone height increase (1.0 mm), resulting in 21% coverage of original threads. Histometric measurements verified that the MRET sites had the least distance from the top of the fixture to the newly formed bone level (0.4 mm). However, in contrast with the clinical findings, the histometric analyses showed that the MRB group had the greatest remaining bone defect (3.3 mm). The clinical and histometric results of the MRET group were statistically better, though, compared with those of the other two groups. Biopsies, removed from beneath the membranes, revealed slightly inflamed connective tissue, containing spicules of newly formed bone, indicating that more bone might have been created if the membranes had been retained longer.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗
PubMed1992

Root resorption following traumatic dental injuries.

Permanent teeth are usually not attacked by osteoclasts despite their situation in a site where active bone resorption constantly takes place as a result of local and systemic osteoclast activating factors. This fact points to antiresorption factors residing in both the periodontal ligament (PDL) and the pulp. Concerning the PDL homeostasis factor (i.e. permanency of a separation between the alveolar socket and the root surface and protection of the root surface against osteoclastic activity), recent studies have shown that this factor, at least with respect to trauma and wound healing, is linked to, and probably resides in, the cementoblast layer and/or the cells next to this layer. If there is loss of this tissue integrity, root resorption may occur; especially if non-PDL derived cells gain access to the site. With respect to the pulp, no systematic research has been performed regarding the homeostasis of this structure (i.e. permanency of the pulpal organ with its specific anatomy and functional stability). In evaluating the events where resorption does occur, it appears that the loss of tissue components within the pulp (including odontoblasts) implies a risk of root canal resorption if nonpulpally derived cells gain access to the site. Root resorption following traumatic dental injuries, whether located along the root surface or within the root canal appears to be a sequel to wound healing events, where a significant amount of the PDL or pulp has been lost due to the effect of acute trauma. The goal of these processes is removal of injured tissue from zones of trauma, space creation for neovascularization or control of infection. Irrespective of the goal, these processes have a potential for root resorption. The type of tissue repair, i.e. repair originating from the dental pulp, the PDL or bone or a combination, seems to be of importance in determining the risk of root resorption during the healing process.

Dental Pulp↗
PubMed1992

A comparison of ePTFE membranes alone or in combination with platelet-derived growth factors and insulin-like growth factor-I or demineralized freeze-dried bone in promoting bone formation around immediate extraction socket implants.

The purpose of this study was to compare bone promotion around implants which were augmented with ePTFE membranes alone or in combination with cortical demineralized freeze-dried bone (DFDB) or the combination of platelet derived growth factor-BB (PDGF) and insulin like growth factor I (PDGF/IGF-I). Membranes were placed over titanium implants which had been inserted into fresh extraction sockets with large buccal dehiscences. Twenty-four implants were placed in 4 dogs. At 18 weeks clinical bone height measurements were taken, the animals were sacrificed, and all specimens retrieved for histologic evaluation. Clinically, a significant gain in bone levels was present in both the ePTFE membrane alone group (P < 0.005) and PTFE plus PDGF/IGF-I group (P < 0.01), but not in the PTFE plus DFDB group. Results from histometric measurements revealed an approximately 2-fold increase in the percentage of implant surface in contact with bone, area of bone adjacent to the implant surface, and in the total length of the implant surface in contact with bone in the dehiscence defects treated with ePTFE plus PDGF/IGF-I compared to the defects receiving ePTFE membranes alone (each P < 0.05). The response to the DFDB was highly variable and it did not significantly improve the efficacy of the PTFE membranes for any parameter measured. The distance from the outer surface of the new bone to the implant surface was statistically significant for ePTFE membranes alone and membranes plus PDGF/IGF-I. The results demonstrated that clinically, ePTFE membranes alone or ePTFE membranes with PDGF/IGF-I were equally effective in promoting bone growth around the implants. Histologic measurements demonstrated that sites treated with ePTFE membranes plus PDGF/IGF-I had the highest bone density compared with sites which received ePTFE membranes alone or with ePTFE membranes and DFDB. The results of this study question the use of DFDB and support the use of ePTFE membranes alone or with PDG-F-BB/IGF-I as potential methods of promoting bone formation around dental implants.

Alveolar Bone Loss↗
PubMed1992

Analysis of low affinity nerve growth factor receptor during pulpal healing and regeneration of myelinated and unmyelinated axons in replanted teeth.

Nerve regeneration was examined in rat molars that were briefly extracted and then replanted in the socket for 1-90 days. Immunocytochemistry was used to evaluate neural and nonneural immunoreactivity (IR) for low affinity nerve growth factor receptor (p75-NGFR) and for laminin and calcitonin gene-related peptide (CGRP). Three different types of pulpal response to replantation were found. Type I: Some replanted teeth had mild injury and still contained coronal odontoblasts and associated fibroblasts that retained p75-NGFR-IR; they continued regular dentin formation and had excellent reinnervation. Type II: Teeth with intermediate injury lost most or all of the coronal pulp tissue, but they regenerated odontoblast-like cells that formed irregular dentin, they had numerous dispersed p75-NGFR-IR fibroblasts in crown pulp during early regeneration, and they had excellent reinnervation. Type III: Severely injured teeth lost their original pulp; they filled with dense connective tissue and bone and had poor reinnervation. After Type I or II injury the Schwann cells around degenerating myelinated and unmyelinated axons had increased expression of p75-NGFR by 1-3 days. By 7-10 days those Schwann cells had formed hollow tubes (bands of Bungner) along the degenerating axon tracks. They maintained their increased p75-NGFR-IR during and after regeneration of unmyelinated axons, whereas Schwann cells involved in remyelination lost p75-NGFR-IR at that stage. The number of CGRP-IR axons in the regenerating pulp increased from 7 to 90 days. Laminin-IR increased in all replanted teeth at 3-10 days and only returned to normal patterns in teeth with Type I or Type II response at 20-90 days. The special p75-NGFR-IR of pulpal fibroblasts of adult rat molars did not usually persist in regenerated, reinnervated pulp. The extensive depletion of fibroblast p75-NGFR-IR and the continuing enhanced p75-NGFR-IR in unmyelinated nerve fibers at 90 days show that altered growth factor conditions characterize regenerated pulp of replanted teeth.

Animals↗
PubMedDate not supplied

Variations in bone regeneration adjacent to implants augmented with barrier membranes alone or with demineralized freeze-dried bone or autologous grafts: a study in dogs.

A study was performed in two large hound dogs to evaluate the bone-induction potential of demineralized freeze-dried bone (DFDBA) placed into defects adjacent to implants that were placed into extraction sockets. Two implants were untreated controls, two implants received only Gore-Tex Augmentation Membrane (GTAM), two implants received GTAM and autologous bone, and six sites received GTAM and DFDBA. DFDBA was prepared from the long bones of a dog of the same breed as the experimental dogs. P2, P3, and P4 were extracted bilaterally, and buccal defects were created and measured. Twelve commercially pure titanium Brånemark implants were placed. At 12 weeks, clinical measurements were taken and the dogs were sacrificed. The untreated control defects had a mean clinical bone fill of 1.75 mm (37%). Sites treated with autologous bone had a mean of 5.0 mm (95%) of clinical bone fill within the original defects. Sites treated with DFDBA and barriers had 3.8 mm (75%) of bone fill, while sites treated with membranes alone had a mean of 4.2 mm (80%) of bone fill. Histologic evaluation revealed that DFDBA sites had retained nonviable bone chips in 45.4% of the bone matrix, and only 8.3% was lamellar bone. Autologous graft sites had 26.2% retained bone chips within the bone matrix, and 61% percent of the matrix consisted of lamellar bone. For GTAM-only sites, 70.2% of the matrix was lamellar bone and 29.8% was woven bone. Retained DFDBA bone chips were nonviable, occasionally surrounded by woven bone, and appeared to break up and then remineralize without the presence of osteoclastic or osteoblastic activity. Retained autologous bone chips were surrounded and incorporated by the host bone. The autologous bone grafts and DFDBA implants were considered to be osteoconductive. For the three treatment groups, within the defects there were sparse bone-implant contacts. The results indicate that GTAM barriers alone or with autologous bone grafts produced the best clinical and histologic results. DFDBA did not appear to induce bone formation in any of the evaluated specimens.

Alveolar Process↗
PubMed1996

Clinical and histologic observations of sites implanted with intraoral autologous bone grafts or allografts. 15 human case reports.

The cases reported in this paper were treated at 7 different clinical centers and present clinical and histologic observations from 15 patients and 21 human biopsies. The biopsies were taken from extraction sockets or dental implant sites which were grafted with either autologous intra-oral bone (6 sites), demineralized freeze-dried bone (DFDBA) (7 sites), or mineralized freeze-dried bone (MFDBA) (7 sites), or a combination of autologous bone, DFDBA and a barrier membrane (1 site). Six sites were grafted with DFDBA and augmented with expanded polytetrafluoroethylene (ePTFE) barrier membranes. Biopsies for histological evaluation were taken 4 to 13 months after implantation. A bone scoring system of 0 to 4 was used to evaluate the sections for dead implanted particles or the presence of vital bone. A bone score of 3 indicated the presence of dead implant material, blood vessels, islands of cartilage, osteoblasts, and new bone formation. A score of 4 indicated total replacement of the implanted material by the host bone. The average bone score for sites which received autologous bone was 2.33; for DFDBA sites, 0.98; and MFDBA was 0.18. The over-riding histologic characteristic of sites implanted with DFDBA or MFDBA was retention of non-vital graft particles within fibrous connective tissue. Biopsies taken adjacent to the host bed demonstrated incorporation of the allografts (osteoconduction). Sites grafted with autologous bone chips also demonstrated non-vital bone chips surrounded by vital host bone (osteoconduction). Sites which received barrier membranes did not appear to improve or impair bone healing of the augmented sites. Autologous bone chips harvested from within the oral cavity as well as allografts may serve as biologic fillers, but do not apparently contribute to osteoinduction. Autologous bone will eventually be resorbed and replaced by the host. DFDBA and MFDBA are resorbed very slowly and apparently do not contribute to osteoinduction. Allografts apparently are not resorbed by osteoclasts and therefore their continued use around dental implants is questioned.

Adult↗