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Changes in craniofacial development due to modifications of the treatment of unilateral cleft lip and palate.

OBJECTIVE: The objective of this study was to evaluate the craniofacial morphology of children with unilateral cleft lip and palate (UCLP) resulting from differing management protocols practiced in Prague from 1945 to 1976. DESIGN: The craniofacial morphologies of four groups of patients were compared. Two groups were assessed retrospectively (individuals born from 1945 to 1963), and two groups were followed on a longitudinal basis (individuals born from 1966 to 1976). SETTING: The study was conducted at the Cleft Lip and Palate Center at the Department of Plastic Surgery, Prague, which has a catchment area population of 6 million. PATIENTS: The subjects were a consecutive series of adult males (n = 84) who had complete UCLP without associated malformations. INTERVENTIONS: Patients born from 1945 to 1955 did not receive centralized orthodontic therapy. From 1945 to 1965, the alveolar process in the area of the cleft was not surgically repaired. Primary bone grafting was used for the group born from 1965 to 1972, and primary periosteoplasty was used in the subsequent period. Throughout the period covered by the study, the palate was operated on by pushback and pharyngeal flap surgery. From 1945 to 1965, the lip was repaired initially according to Veau, and later according to Tennison and Randall, and during this time, fixed appliances were used for orthodontic treatment. RESULTS: The results for the period from 1945 to 1955 are characterized by mandibular overclosure with anterior crossbite. Centralized orthodontic treatment in the later period improved sagittal jaw relations due to the posterior displacement of the mandible and an edge-to-edge bite was attained, but maxillary retrusion was unchanged. Primary bone grafting increased retrusion of the maxilla, which was compensated by further posterior displacement of the mandible. An edge-to-edge bite was also obtained. Primary periosteoplasty reduced maxillary retrusion, and the marked proclination of the upper dentoalveolar component with fixed appliances resulted in a positive overjet. It was no longer necessary to push the mandible back to the extent required in bone grafting. CONCLUSION: Effective orthodontic treatment made the greatest contribution to improved facial development. It allowed compensation of maxillary retrusion by changes in the position of the mandible or by proclination of the upper dentoalveolar component with fixed appliances. The applied surgical methods using primary bone grafting caused deterioration of the anterior growth of the maxilla.

Adult↗

Dental abnormalities, bone graft quality, and periodontal conditions in patients with unilateral cleft lip and palate at different phases of orthodontic treatment.

OBJECTIVES: To evaluate the dental and periodontal condition of patients with unilateral cleft lip and palate (UCLP) before orthodontic treatment and evaluate whether the dental and periodontal condition of these patients during and after orthodontic treatment was jeopardized by the duration of the orthodontic and surgical treatment. DESIGN: Seventy-five individuals with UCLP (52 males, 23 females), between ages 8 and 20 years, participated in a retrospective study during their final follow-up visit with regard to dental abnormalities, such as hypodontia, external root resorption, crown and root malformation, and supernumerary teeth. Alveolar bone height and periodontal attachment loss on the cleft side were also screened before or after bone grafting and at different stages of orthodontic treatment. RESULTS: Hypodontia of the lateral incisor was found in more than 50% of the patients on the cleft side. Second premolars and/or lateral incisors outside the cleft area were missing in 27.2% of the patients. In 32%, malformations of the teeth near the cleft were noticed. In general, the teeth around and in the cleft of the patients showed normal septal bone heights and a healthy periodontium. Sixty of the 75 patients received a bone graft to restore the interrupted alveolar process. In 93.3% of these patients, the cleft was grafted before the eruption of the canine. CONCLUSION: The periodontium of the teeth in and around the cleft in patients with UCLP observed during and after orthodontic treatment can cope relatively well with the long orthodontic treatment and combined surgical interventions. The children, who had not yet started treatment, also showed enough bone support and no periodontal problems of the teeth besides the cleft. Early secondary bone grafting seems to give optimal periodontal results.

Adolescent↗

Three-year post-placement survival of implants mobile at placement.

BACKGROUND: Although rigid fixation of endosseous implants at the time of placement is generally thought to be a prerequisite for successful osseointegration, the Dental implant Clinical Research Group (DICRG) of the Department of Veterans Affairs has reported on implants that integrated despite being mobile at placement. The present study examines the frequency of osseointegration and the 36-month post-placement survival of implants mobile at placement in a prospective, multicenter, longitudinal clinical study of more than 3,000 implants conducted by the DICRG. METHODS: A total of 3,111 implants of 6 different designs were placed in all jaw regions in more than 800 patients at 32 study centers. At the time of this report, 2,770 of these implants had been followed for 36 months post-placement. They included 89 implants that were mobile at placement. Data for demographic variables, implant coating, bone quality, incision type, bone augmentation, and antibiotic usage were recorded. An electronic hand-held probe was used to measure mobility at uncovering and at regular follow-up intervals. RESULTS: Eighty-nine of 2,770 inserted implants were mobile at placement. Results are reported for two periods: from placement to 36 months and from prosthetic loading to 36 months. The latter method eliminated early failures and resulted in substantially higher scores for both mobile implants at placement (95.9% survival from prosthetic loading to 36 months post-placement versus 79.8% from placement to 36 months) and implants not mobile at placement (98.4% versus 93.4%). Mobility at placement was significant to 3-year survival (P < 0.001). Hydroxyapatite (HA) coating improved the performance of implants mobile at placement (91.8% for HA-coated versus 53.6% for non-HA) and those not mobile at placement (97.2% for HA-coated versus 87.4% for non-HA). Radiographic findings suggested that crestal bone response around implants which were mobile versus immobile at placement was similar. CONCLUSIONS: Although implant stability at the time of placement is clearly desirable as seen in the superior 3-year survival of stable implants, it may not be an absolute prerequisite to osseointegration or to long-term survival. Several factors may influence the decision to remove or replace a mobile implant. HA-coating significantly improved the performance of both mobile and immobile implants at placement to 3 years post-placement (P < 0.001).

Adult↗

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↗

Effects of tetracycline HCl conditioning and fibrin-fibronectin system application in the treatment of buccal gingival recession with guided tissue regeneration.

A split-mouth clinical trial was designed to evaluate the effect of treating deep wide buccal gingival recession with guided tissue regeneration using expanded polytetrafluoroethylene membrane combined with tetracycline HCl (TTC) root conditioning and fibrin-fibronectin sealing system (FFSS) application. Eight patients, aged 25 to 57 years, each presenting two similar mucogingival defects, were selected. The two bilateral recessions were randomly assigned in each patient to either test or control treatment procedure. After initial therapy, each patient was examined for assessment of plaque, gingivitis, recession depth (RD), probing depth (PD), probing attachment level (PAL), and keratinized tissue width (KT). The test procedure included the elevation of mucoperiosteal flap at the buccal aspect of the alveolar process. The root was debrided and demineralized with 100 mg/ml TTC solution for 4 minutes using a burnishing technique with cotton pellets. A teflon membrane was secured and a film of FFSS was applied between the membrane and the root surface. The buccal flap was sutured to completely submerge the membrane. Control treatment included gingival flap surgery with barrier membrane alone. After 6 weeks, the membrane was removed. Healing was evaluated 6 months after surgery. Both test and control procedures resulted in highly significant recession reduction (3.0 mm +/- 1.1 and 2.6 mm +/- 1.2, respectively) and attachment gain (3.6 mm +/- 1.7 and 2.6 mm +/- 1.1, respectively). Mean root coverage was of 67% in the TTC + FFSS treated sites and 60% in membrane-only treated sites. However, only treatment with TTC + FFSS significantly reduced PD and increased KT (P < 0.05). When treatments were compared, changes in PD and PAL were significantly greater in TTC + FFSS treated sites (P < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Devices for dentoalveolar regeneration: an up-to-date literature review.

Regeneration of periodontal and alveolar ridge defects utilizing barrier membranes has become well established in clinical dentoalveolar reconstruction. Application of this technique has evolved from the concept of separating tissues during healing to that of providing a healing environment capable of regeneration of functional structures. The biomaterial characteristics and design of membranes employed in this technique play an important role in establishing and maintaining this environment. Barrier membranes must incorporate specific features that address the biological, mechanical, and clinical use requirements involved in regenerative treatment. Although nondegradable materials require a second surgical procedure for removal, these materials simplify certain aspects of development, production, and clinical regenerative treatment for some applications. Degradable materials introduce specific considerations and limitations regarding material selection, design, and clinical application. The progressive breakdown of degradable membranes results in dynamic changes in the mechanical and biocompatibility profiles of these materials. With present technology, these factors may limit use of degradable materials to specific applications. Membrane materials, therefore, should be selected based on a thorough understanding of the benefits and limitations inherent to the material(s) in relation to the functional requirements of specific clinical applications.

Alveolar Process↗

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↗

The application of deproteinized bovine bone mineral for ridge preservation prior to implantation. Clinical and histological observations in a case report.

Alveolar ridge preservation following tooth extraction is important when implant-supported oral rehabilitation is considered. The ability to maintain the ridge allows implant placement in an ideal position, fulfilling both functional and esthetic demands. A deproteinized bovine bone mineral (DBBM) was used as a socket site filler material to maintain ridge configuration, without applying an occlusive membrane. The material was grafted and packed onto the socket sites immediately after extractions, and subsequently primary soft tissue closure was attempted. The ridge healed for 9 months before the second surgical procedure, in which the implant was placed. New bone formation was observed in all histological specimens. DBBM particles adhered to a highly osteocyte-rich woven and lamellar-type bone. Clinically and histologically, this report demonstrated DBBM particles to be an effective biocompatible filler agent in extraction sockets for ridge preservation prior to titanium fixture implantation. Randomized controlled clinical trials are needed to fully evaluate the usefulness of this material in ridge preservation after tooth extraction.

Adult↗

Changes in alveolar bone height and width following ridge augmentation using bone graft and membranes.

BACKGROUND: Clinical observation suggests the amount of bone height and width created during guided bone regeneration (GBR) to augment alveolar ridges is not retained during healing. A study was designed to determine: 1) whether the amount of osseous structure 4 months postoperatively after GBR was significantly less than the amount surgically created; and 2) if this change was uniform over the area treated. METHODS: Nineteen extraction sites (10 patients) were treated with GBR prior to placing endosseous implants. Allograft (DMFDB) and a bioabsorbable membrane were employed. Standardized measurements were taken of alveolar height and width 1) prior to augmentation; 2) after placement of graft and membrane; and 3) following 4 months of healing. Width measurements were taken 3 mm, 5 mm, and 10 mm from the crest at 3 intervals: the mesio-distal midpoint of the edentulous area and 3 mm mesial and distal to the midpoint. Height measurements were recorded at the mesio-distal midpoint and points 3 mm mesial and distal to the midpoint. RESULTS: Loss in width of supplemented bone after 4 months of healing ranged from 52.1% to 58.0% 3 mm from the crest, 47.6% to 67.4% 5 mm from the crest, and 39.1 % to 46.7% 10 mm from the crest. Loss of augmented height averaged 14. 7% in the center of the edentulous area but ranged from 60.5% to 76.3% 3 mm mesial and distal to the midpoint. CONCLUSIONS: The results indicate significant non-uniform loss of augmented alveolar height and width during GBR healing. The implications of these findings impact preoperative augmentation planning for endosseous implantology.

Alveolar Bone Loss↗

Porous bovine bone mineral in healing of human extraction sockets. Part 1: histomorphometric evaluations at 9 months.

BACKGROUND: Extraction socket wound healing is characterized by resorption of the alveolar bone at the extraction site. This produces a decrease in ridge volume, deformations of ridge contours, and, thus, difficulties in delayed placement of root-form implants in an ideal position. Cancellous porous bovine bone mineral (PBBM) applied to fresh extraction sockets has recently been proposed to minimize the reduction in ridge volume. The aim of this study was to investigate the influence of PBBM grafted particles on the histopathologic pattern of the intrasocket regenerated bone and to evaluate histomorphometrically the healed PBBM grafted extraction socket site at 9 months' post-extraction. METHODS: PBBM particles (250 to 1,000 microns in size) were grafted in 15 fresh human extraction sockets in 15 patients. Socket wall bone height was measured from the crestal ridge level before the mineral particles were inserted. Primary soft tissue closure was performed to protect the grafted particles via a pediculated split palatal flap. At 9 months, socket bone walls were remeasured and cylinder bone samples of the previously PBBM-grafted sites were obtained. Decalcified specimens were sectioned at a cross-horizontal plane and stained with hematoxylin and eosin for histopathologic and histomorphologic examination. Tissue area percentage of bone, PBBM, and connective tissue (CT) was calculated for each specimen from the crestal to the apical region and changes in values compared. RESULTS: Average clinical overall bone fill of the augmented socket sites was 82.3%. Histologically, PBBM particles were observed in all specimens. Newly formed bone was characterized by abundance of cellular woven-type bone in the coronal area, while lamellar arrangements could be identified only in the more apical region. New osseous tissue adhered to the PBBM. Histomorphometric measurements showed an increase of mean bone tissue area along the histological sections from 15.9% in the coronal part to 63.9% apically (average 46.3%). CT fraction decreased from 52.4% to 9.5% (average 22.9%) from the crestal to the apical region. PBBM area fraction varied from 26.4% to 35.1% (average 30.8%). Statistical analysis of the comparison between areas of bone, CT, and PBBM was performed in different points along the coronal-apical axis. Differences were significant (P <0.01) at the most crestal, middle, and apical section cut areas, but not at the cervical section cuts. Bone area fraction increased in the apical direction as much as CT correlatively decreased. Unlike CT and bone, PBBM retained constant relative volume (approximately 30%), regardless of the depth of the specimen cores. CONCLUSIONS: PBBM particles are an appropriate biocompatible bone derivative in fresh extraction sockets for ridge preservation. The resorbability of this xenograft could not be recognized in a 9-month period. Further investigation is needed to clarify the resorptive mechanisms of PBBM.

Adult↗

Evaluation of recombinant human bone morphogenetic protein-2 in oral applications including the use of endosseous implants: 3-year results of a pilot study in humans.

BACKGROUND: This study evaluated patients who had been treated with recombinant human bone morphogenetic protein-2 (rhBMP-2) loaded in an absorbable collagen sponge (ACS) in human extraction sites or in sites that required alveolar ridge augmentation. An earlier report on the same patients revealed that after 4 months, implantation of rhBMP-2/ACS was safe, as determined by clinical, radiographic, systemic, and immunological analyses. In this longer-term follow-up, eligible patients were restored with endosseous dental implants in the area treated with rhBMP-2/ACS and bone biopsy samples were taken for histological analysis of the treated human bone tissue. The primary objective was to monitor the long-term safety of patients treated with rhBMP-2/ACS. Another objective was to evaluate the dental implants placed in the sites treated with rhBMP-2. METHODS: Patient safety was evaluated by clinical examinations, periapical radiographs, and occurrence of adverse experiences. Dental implants were evaluated by radiographic and clinical examination. All 12 patients have been followed for 3 years. RESULTS: Two years following surgical implantation of rhBMP-2/ACS, no serious or unexpected adverse experiences occurred. The adverse experiences that did occur were mostly benign and compatible with the dental implant surgeries performed in these patients. No adverse experiences were deemed as related to the rhBMP-2/ACS. Furthermore, no safety concerns in the local area of rhBMP-2/ACS placement were noted, based on oral wound examinations. In the 10 patients (6 extraction socket patients and 4 augmentation patients) who received endosseous implants, all implants were clinically stable at all assessments and all 10 patients have been functionally restored. Histological evaluation of the human bone core biopsies revealed normal bone tissue formation identical to the surrounding native bone. Three-year follow-up clinical examinations revealed that all implants had stable marginal bone levels and healthy peri-implant tissues. CONCLUSIONS: These 3-year results demonstrate that rhBMP-2/ACS can be used safely in human patients. Human bone biopsies reveal normal bone formation in areas treated with rhBMP-2/ACS. Endosseous implants placed in these areas were all stable with no radiographic or clinical complications. The results from this study suggest that rhBMP-2/ACS (0.43 mg/ml) can be safely used in tooth extraction sites and in local ridge augmentation procedures and that endosseous dental implants placed in bony areas treated with rhBMP-2/ACS are stable and can be functionally restored without complication.

Alveolar Process↗

Hyaluronan supports recombinant human bone morphogenetic protein-2 induced bone reconstruction of advanced alveolar ridge defects in dogs. A pilot study.

BACKGROUND: Prosthetic-driven implant dentistry requires predictable procedures for alveolar ridge augmentation. The objective of this pilot study was to evaluate bone regeneration in mandibular, full-thickness, alveolar ridge, saddle-type defects following surgical implantation of recombinant human bone morphogenetic protein-2 (rhBMP-2) in a novel hyaluronan (HY) sponge carrier. This sponge was fabricated from auto-crosslinked HY. METHODS: Alveolar ridge defects (approximately 15 x 10 x 10 mm), 2 per jaw quadrant, were surgically prepared in each of 3 young adult American fox hounds. Four defects were immediately implanted with rhBMP-2/HY. Three defects were implanted with rhBMP-2 in an absorbable collagen sponge (ACS) carrier (positive control). The rhBMP-2 solution (1.5 ml at 0.2 mg/ml) was soak-loaded onto the HY and ACS sponges. Three defects were implanted with HY sponges soak-loaded with buffer without rhBMP-2 (negative control), while 2 defects served as surgical controls. The animals were euthanized at 12 weeks postsurgery for histometric analysis. RESULTS: Clinically, alveolar ridge defects receiving rhBMP-2/ACS exhibited a slight supracrestal expansion, while defects receiving rhBMP-2/HY were filled to contour. In contrast, the HY and surgical controls exhibited ridge collapse. rhBMP-2/HY-treated defects exhibited a dense bone quality without radiolucent regions observed in defects treated with rhBMP-2/ACS. The histometric analysis showed 100% bone fill for the rhBMP-2/ACS defects and 94%, 58%, and 65% bone fill for the rhBMP-2/HY, HY, and surgical control defects, respectively. CONCLUSIONS: The conclusions are based on data from 2 of 3 animals in the study. In one animal, no response to rhBMP-2 was observed with either carrier, and the animal may have been a non-responder of unknown nature. With this limitation, the observations herein suggest that: 1) HY supports significant bone induction by rhBMP-2; 2) the rhBMP-2-induced bone assumes qualities of the immediate resident bone; 3) HY alone exhibits no apparent osteoconductive potential; and 4) HY appears to resorb within a 12-week healing interval in the absence or presence of rhBMP-2. Thus, HY appears to be a suitable candidate carrier for rhBMP-2.

Absorbable Implants↗

Distraction osteogenesis and histogenesis in beagle dogs: the effect of gradual mandibular osteodistraction on bone and gingiva.

BACKGROUND: No study has systematically evaluated the effect of distraction osteogenesis on the gingival tissues. Therefore, this study was designed to analyze the newly formed bone and gingiva during the consolidation period of mandibular osteodistraction using standard histologic techniques. METHODS: Seventeen skeletally mature male beagle dogs underwent 10 mm of bilateral interdental mandibular lengthening. After distraction, the regenerates were allowed to consolidate for 0, 2, 4, 6, or 8 weeks, then the animals were sacrificed and tissues harvested for analysis. RESULTS: Mineralization began at the host bone margins at the end of the distraction period, followed by a progressive increase in bone surface area, with a concomitant decrease in fibrous tissue. The gingiva initially underwent mild inflammatory and reactive changes during distraction and during the first few weeks of consolidation. The rate of bone formation gradually increased from the end of distraction to the fourth week of consolidation, at which time it remained constant until sometime before the eighth week, when it tapered off slightly as remodeling began. From the second through the eighth week of consolidation, regenerative changes and neohistogenesis were seen in the gingival tissues. CONCLUSIONS: Osteodistraction has the potential to drastically decrease the total treatment time for alveolar bone augmentation prior to dentoalveolar implant placement since the regenerate bone rapidly mineralizes within approximately 8 to 10 weeks after the distraction period and the gingiva responds favorably to increased length by regeneration rather than by degeneration. Although the results appear favorable, similar data should be evaluated in human clinical trials.

Alveolar Process↗

Changes in alveolar bone height and width following post-extraction ridge augmentation using a fixed bioabsorbable membrane and demineralized freeze-dried bone osteoinductive graft.

BACKGROUND: It has been shown that the amount of healed bone following guided bone regeneration (GBR) with demineralized freeze-dried bone allograft (DFDBA) and a bioabsorbable membrane is significantly less than the initial quantity. A study was designed to determine if the amount of GBR would be affected by using an osteoinductive DFDBA and bioabsorbable membrane and membrane stabilization. METHODS: Eleven extraction sites (10 patients) were treated with DFDBA and bioabsorbable membrane before placing endosseous implants. Standardized alveolar height and width measurements were taken after extraction, GBR, and 4 months postoperatively, at predetermined measurement points (sites midpoint and 3 mm mesial and distal from the midpoint) and classified as augmented (<1 mm increase of GBR height or width) or grafted (>1 mm increase). Five membranes were stabilized. RESULTS: Three mm from the crest, augmented points exhibited a complete loss of augmented width. There was also some loss of pre-GBR bone width (ranging from 4.7% to 20%) at augmented and grafted points. Five mm from the crest, augmented points lost 83.3% to 92.3% of augmented width and grafted points lost 12.9% to 18% of pre-GBR width. Loss of augmented height ranged from 93.5% to 100%. Augmented (except distal) and grafted measurement points lost 2.1% to 12% of pre-GBR height. Comparing tacked and non-tacked sites, the former manifested less loss of augmented bone width, the latter augmented bone height. CONCLUSIONS: Results indicate a complete loss of augmented width 3 mm from the crest and almost complete loss in height and width 5 mm from the crest. Membrane stabilization appeared beneficial.

Absorbable Implants↗

Effect of recombinant human bone morphogenetic protein-2 in an absorbable collagen sponge with space-providing biomaterials on the augmentation of chronic alveolar ridge defects.

BACKGROUND: Recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) carrier has been shown to support significant bone formation in the craniofacial skeleton. When used as an onlay, however, rhBMP-2/ACS may become compressed with limited resulting bone formation. The objective of this study was to evaluate the effect of two space-providing biomaterials, bioactive glass (BG) and demineralized/mineralized bone matrix (DMB), on rhBMP-2/ACS induced alveolar ridge augmentation. METHODS: Bilateral alveolar ridge defects were produced in the mandible in six mongrel dogs. rhBMP-2/ACS with biomaterials was surgically implanted into contralateral defects in four animals. Treatments were alternated between jaw quadrants in consecutive animals. Two animals received rhBMP-2/ACS or sham-surgery in contralateral defects. The animals were injected with fluorescent bone labels to monitor bone formation. Clinical evaluations were made at ridge augmentation and 12 weeks post-implantation when the animals were euthanized and block biopsies collected for histopathologic evaluation. RESULTS: Sham-surgery produced limited horizontal alveolar augmentation (0.1 +/- 0.6 mm). Implantation of rhBMP-2/ACS resulted in alveolar augmentation amounting to 2.2 +/- 1.8 mm. Alveolar augmentation in sites receiving rhBMP-2/ACS with DMB or BG was 2-fold greater compared to rhBMP-2/ACS alone averaging 4.4 +/- 1.3 and 4.6 +/- 1.5 mm, respectively. The DMB biomaterial appeared substituted by newly formed bone. The BG particles were observed imbedded in bone or encapsulated in dense connective tissue without associated bone metabolic activity. Fluorescent light microscopy suggested that the new bone was formed within 4 weeks. CONCLUSION: The bioglass and demineralized/mineralized bone matrix biomaterials utilized in this study in combination with rhBMP-2/ACS supported clinical and histological ridge augmentation.

Alveolar Bone Loss↗

Sinus lift procedure of the maxilla in patients with inadequate bone for dental implants: radiographic appearance.

OBJECTIVE: Dental implants have gained popularity for treating edentulism, but some patients develop jaw atrophy, which leaves insufficient bone for implants. To treat these patients, the sinus lift procedure, which augments bone, was developed. Altered anatomy from this procedure has an unusual radiographic appearance, confusing those unfamiliar with it. We describe the sinus lift procedure and its radiographic appearance. CONCLUSION: With knowledge of this surgery and some of its pitfalls, radiographs can be more easily and accurately interpreted.

Aged↗

The superior alveolar nerves: their topographical relationship and distribution to the maxillary sinus in human adults.

The superior alveolar nerves in human adults were investigated macroscopically using whole-mount silver impregnation, paying special attention to their topographical relationship and distribution to the mucous membrane of the maxillary sinus. In addition, the fiber composition of the alveolar nerves was analysed in order to estimate their contribution to teeth innervation. The posterior superior alveolar nerve (PSAN) ran through canaliculi in the lateral wall of the sinus (23 of 37 cases, 62.2%) or under the mucous membrane of the sinus (14 of 37 cases, 37.8%). Moreover, the PSAN gave off many fine twigs to make complex plexus under the mucous membrane of the sinus before joining the superior dental plexus. The plexus of the maxillary sinus was separated from the superior dental plexus by the bony wall of the sinus. After the above gross observations, the perimeter compositions of myelinated fibers of the plexus, PSAN and the anterior alveolar nerve were analysed in the same specimen. The plexus was composed of myelinated fibers of less than 27 microns in circumference perimeter (mean: 14.3 microns) and numerous unmyelinated fibers. The fiber composition suggested that few fibers in the plexus of the maxillary sinus contribute to the formation of the superior dental plexus. The superior dental plexus, innervating the upper teeth, was located in the thick alveolar process of the maxilla, and not on the maxillary sinus wall. The clinical importance of these results was discussed in relation to nerve injury during antrostomy of the maxillary sinus.

Aged↗