Guided bone augmentation using ceramic space-maintaining devices: the impact of chemistry.

The purpose of the study was to evaluate histologically, whether vertical bone augmentation can be achieved using a hollow ceramic space maintaining device in a rabbit calvaria model. Furthermore, the chemistry of microporous hydroxyapatite and zirconia were tested to determine which of these two ceramics are most suitable for guided bone generation. 24 hollow domes in two different ceramic materials were placed subperiosteal on rabbit skull bone. The rabbits were sacrificed after 12 weeks and the histology results were analyzed regarding bone-to-material contact and volume of newly formed bone. The results suggest that the effect of the microporous structure of hydroxyapatite seems to facilitate for the bone cells to adhere to the material and that zirconia enhance a slightly larger volume of newly formed bone. In conclusion, the results of the current study demonstrated that ceramic space maintaining devices permits new bone formation and osteoconduction within the dome.

Four-Millimeter-Long Posterior-Mandible Implants: 5-Year Outcomes of a Prospective Multicenter Study.

BACKGROUND: There is lack of evidence on long-term success of short dental implants in reduced alveolar bone. PURPOSE: In this prospective 5-year study, survival and marginal bone loss of 4-mm implants, which supported fixed dental prostheses (FDPs) in severely resorbed posterior mandibles, were evaluated. MATERIAL AND METHODS: In 28 patients, evaluation of 86 osseointegrated 4-mm-long implants, which supported a 3- or a 4-unit FDP by crown splinting without the use of pontics or cantilevers, was performed over a 5-year period. RESULTS: Three subjects dropped out for non-study reasons: one subject had her three implants removed after 1 year and two subjects died (six implants). Five implants in three subjects were lost between 3 and 5 years. Twenty-four subjects and 71 implants were active at the 5-year follow-up (92.2% survival). After 1 year, significant (p < .001) mean (standard error of the mean [SEM]) 0.44-mm (0.05) marginal bone loss occurred. At 2, 3, and 5 years, mean (SEM) bone loss of 0.57 mm (0.06), 0.55 mm (0.07), and 0.53 mm (0.08) occurred, respectively (no significant change after 1 year). At 5 years, average plaque levels were 13.3%; 69% of the implants were plaque free. On average, mucosal bleeding occurred at 8.1% of the implants. During 5 years, two subjects experienced uncomplicated bridge loosening. No other complications occurred during the study. CONCLUSION: Four-millimeter implants can support FDPs in severely resorbed posterior mandibles for 5 years with healthy peri-implant conditions.

Guided bone augmentation using a ceramic space-maintaining device.

OBJECTIVE: The purpose of this study was to evaluate 3-dimensionally whether vertical bone augmentation can be achieved using a hollow hydroxyapatite space-maintaining device in a rabbit calvarial model. Furthermore, different inner surface topographies, different permeabilities, and different porosities of the ceramic were tested to determine the optimal conditions for bone regeneration. STUDY DESIGN: A total of 48 hollow domes made of hydroxyapatite in 4 different designs were placed subperiosteally on rabbit skull bone. The rabbits were humanely killed after 12 weeks, and the results were analyzed 3-dimensionally using micro-computed tomography. RESULTS: The results suggest a larger production of bone volume when using an occlusive, dense hydroxyapatite space-maintaining device with a rough inner surface. CONCLUSIONS: Hydroxyapatite space-maintaining devices permit new bone formation and osteoconduction within the dome.

Evaluation of bone regeneration after three different lateral sinus elevation procedures using micro-computed tomography of retrieved experimental implants and surrounding bone: a clinical, prospective, and randomized study.

PURPOSE: To compare three different lateral sinus elevation procedures concerning new bone formation by using micro-computed tomography (micro-CT) of retrieved implants. MATERIALS AND METHODS: Twenty-four consecutive partially dentate patients with a mean age of 64 years were included in the study and provided with 30 sinus elevation procedures. Three procedures for lateral sinus elevation were used: lateral sinus elevation with replacement of bone window and without bone graft (BW), lateral sinus elevation and covering osteotomy site with a collagen membrane and without bone graft (CM), and lateral sinus elevation with autogenous bone graft (ABG). Experimental implants were retrieved after 7 months of healing and analyzed by micro-CT. RESULTS: One implant was found not to be integrated at the time of implant retrieval. This implant belonged to group CM and was excluded when calculating bone-to-implant contact (BIC) and intrasinus bone levels. The integrity of the lateral sinus bony wall was determined at the time of implant removal. In group ABG, all lateral sinus walls were ossified. In group BW, one lateral sinus wall was not completely ossified and in group CM, two lateral sinus walls. There were no statistical differences in %BIC between the groups: 93.5% (BW), 92.0% (CM) and 93.5% (ABG). Additionally, no statistical differences were found in apical intrasinus bone levels between the groups. When surfaces were compared within the same implant, a statistical difference was found between the apicobuccal distance and the apicolingual distance. The mean apicobuccal distances/apicolingual distances were 0.6 mm/1.2 mm for the BW group, 0.5 mm/0.8 mm for the CM group, and 0.6 mm/0.8 mm for the ABG group (P = .003). CONCLUSIONS: All three procedures were statistically equal when new bone formation was compared. Most of the examined implants' apices were not covered with bone at the time of retrieval.

Periosteal expansion before local bone reconstruction using a new technique for measuring soft tissue profile stability: a clinical study.

PURPOSE: To evaluate the outcome of intraoral soft tissue expansion by measuring the profile change using objective 3D metering equipment and to evaluate localized bone grafting after soft tissue expansion with regard to gain of bone and complications. MATERIALS AND METHODS: Using a prospective study design, we asked patients with an osseous and soft tissue defect on the buccal aspect of the alveolar process to participate in this study. In 10 patients (experimental group) a self-inflatable soft tissue expander was placed under the periosteum. After 2 weeks, the expander was removed and a particulated onlay bone graft was placed in the expanded area, protected by a titanium mesh covered with a collagen membrane. Ten patients (reference group) were treated with a mandibular ramus bone block graft. The soft tissue profile was registered before each surgical procedure. The vertical and lateral dimensions of the bone grafts were noted at the grafting procedure and at the implant installation. P < .05 was considered significant. RESULTS: The mean soft tissue profile change was 2.9 ± 1.1 mm after soft tissue expansion and 2.3 ± 2.1 mm at implant placement in the experimental group compared with 1.5 ± 1.4 mm at implant placement in the reference group (P = .065). Two patients had minor perforations of the soft tissue expander. In the experimental group, the mean lateral bone augmentation after soft tissue expansion was 4.5 ± 1.3 mm, and after healing, it decreased to 3.9 ± 1.4 mm (P = .063). The mean vertical augmentation was 4.1 ± 1.7 mm and had decreased at implant placement to 3.0 ± 1.4 mm (P = .041). In the reference group, the mean lateral augmentation was 3.8 ± 0.8 mm, and after healing, it reduced to 2.7 ± 0.8 mm (P = .024). The mean vertical augmentation was 2.9 ± 0.9 mm, and after healing of the bone graft at implant placement, it was reduced to 1.6 ± 0.8 mm (P = .01). When smokers were excluded, there was significantly less resorption of the bone grafts in both lateral (P = .049) and vertical (P = .012) dimensions in the experimental group compared with the reference group. CONCLUSION: Hydrogel expansion of the periosteum is an applicable method to achieve a surplus of soft tissue to cover bone grafts. More refinements to the technique may be required to minimize complications, especially in smoking patients.

Periapical tissue response after use of intermediate restorative material, gutta-percha, reinforced zinc oxide cement, and mineral trioxide aggregate as retrograde root-end filling materials: a histologic study in dogs.

PURPOSE: To investigate the periapical tissue response of 4 different retrograde root-filling materials, ie, intermediate restorative material, thermoplasticized gutta-percha, reinforced zinc oxide cement (Super-EBA), and mineral trioxide aggregate (MTA), in conjunction with an ultrasonic root-end preparation technique in an animal model. MATERIALS AND METHODS: Vital roots of the third and fourth right mandibular premolars in 6 healthy mongrel dogs were apicectomized and sealed with 1 of the materials using a standardized surgical procedure. After 120 days, the animals were sacrificed and the specimens were analyzed radiologically, histologically, and scanning electron microscopically. The Fisher exact test was performed on the 2 outcome values. RESULTS: Twenty-three sections were analyzed histologically. Evaluation showed better re-establishment of the periapical tissues and generally lower inflammatory infiltration in the sections from teeth treated with the intermediate restorative material and the MTA. New root cement on the resected dentin surfaces was seen on all sections regardless of the used material. New hard tissue formation, directly on the surface of the material, was seen only in the MTA sections. There was no statistical difference in outcome among the tested materials. CONCLUSIONS: The results from this dog model favor the intermediate restorative material and MTA as retrograde fillings when evaluating the bone defect regeneration. MTA has the most favorable periapical tissue response when comparing the biocompatibility of the materials tested.

Four-millimeter implants supporting fixed partial dental prostheses in the severely resorbed posterior mandible: two-year results.

BACKGROUND: Reduced alveolar bone volume complicates implant dentistry. PURPOSE: In this prospective multicenter study, a new, 4-mm long Straumann SLActive implant (Ø 4.1 mm) supporting a fixed dental prosthesis (FDP) in the severely resorbed posterior mandible was evaluated for two years. MATERIAL AND METHODS: Thirty-two patients (11 men, 21 women; mean age 64.1 years) participated. Ten to 12 weeks after single-stage surgery, a screw-retained FDP was attached to three or four 4-mm implants. RESULTS AND DISCUSSION: One hundred implants were inserted. Three failed at surgery and four were lost before loading. Twenty-eight patients received FDPs (93 implants). Two patients were discontinued because of secondary exclusion criteria; therefore, 26 patients were followed up from baseline (BL). After 1 year, one patient insisted on removal of all implants and one patient died because of nonstudy-related complications. Twenty-four patients (87 implants) were eligible for examination 2 years post-loading. All implants were found to be stable [survival rate 95.7% (confidence interval, CI 88.8-98.3) after 1 year and 92.3% (CI 84.5-96.2) after 2 years]. The mean change from BL to 12 months was - 0.43 mm (CI 0.31-0.59; p < .001) and from 12 to 24 months - 0.11 mm (CI -0.01-0.23; p = .056). The survival rate is only slightly lower than in similar studies on 6 to 8.5 mm implants. This may be related to high initial stability and effective use of the residual bone volume with high primary bone-to-implant contact in dense bone structures. The surgical handling of the tested implant was found to be similar to that of implants of common length. However, the preparation procedure must be done with great care to avoid overdrilling. Careful planning and design of the prosthetic construction is mandatory to prevent unfavorable occlusion and avoid harmful shear forces. CONCLUSION: This study showed that 4 mm implants can support an FDP in severely resorbed posterior mandibles for at least 2 years and with healthy peri-implant conditions.

Bone regeneration using a hollow hydroxyapatite space-maintaining device for maxillary sinus floor augmentation--a clinical pilot study.

BACKGROUND: The mere lifting of the maxillary sinus membrane by implants protruding into the sinus cavity allows the establishment of a void space for blood clot and new bone formation. PURPOSE: To evaluate bone formation by using a spherical, hollow, and perforated hydroxyapatite space-maintaining device (HSMD) in a two-stage sinus lift procedure where residual alveolar bone height was ≤2 mm. MATERIAL AND METHODS: Spherical, hollow, and perforated HSMDs with a diameter of 12 mm were manufactured for this pilot study. Three patients with a residual bone height of 1-2 mm, as verified clinically and radiographically, and in need of a sinus augmentation procedure prior to implant installation were selected for the study. The HSMD and bone formation was evaluated by cone beam computerized tomography (CBCT) 6 months after augmentation procedure. Implants were installed 6 to 9 months after augmentation. The implant sites were prepared by a trephine drill to obtain a specimen of HSMD and bone for histological evaluation. After implant installation, the condition of the sinus membrane adjacent to the HSMD was evaluated endoscopically. After an additional 8 weeks, fixed partial prostheses were fabricated. RESULTS: Bone formation verified by CBCT was found around and inside the device in all three patients after 6 months. Despite the fact that residual bone before augmentation was ≤2 mm, 12-mm-long implants with diameter of 4.8 mm could be inserted with preservation of an intact and healthy sinus membrane verified endoscopically. Bone formation inside HSMDs was noted histologically in two out of three HSMDs. Implants were stable and without any marginal bone loss after 1 year of prosthetic loading. CONCLUSION: A spherical, hollow, and perforated HSMD used in sinus lift procedures can produce a void space for blood clot and new bone formation and subsequent implant installation.

Flapless, CBCT-guided osteotome sinus floor elevation with simultaneous implant installation. I: radiographic examination and surgical technique. A prospective 1-year follow-up.

BACKGROUND: Survival rates of implants placed in transalveolar sinus floor augmentation sites are comparable with those placed in non-augmented sites. Flapless implant surgery can minimize postoperative morbidity, alveolar bone resorption and crestal bone loss. The use of cone beam computerized tomography (CBCT) provides 3D presentations with reduced dose exposure. OBJECTIVES: To evaluate a flapless, CBCT-guided transalveolar sinus floor elevation technique with simultaneous implant installation. MATERIAL AND METHODS: Fourteen consecutive patients in need of maxillary sinus floor augmentation were enrolled in this study. Preoperative CBCT with a titanium screwpost as an indicator at the intended implant position was used to visually guide the flapless surgical procedure. Twenty one implants all with a length of 10 mm and a diameter of 4.1 and 4.8 mm were inserted and followed clinically and with CBCT for 3, 6 and 12 months postoperatively. Intraoral radiographs were taken for comparison. All patients were provided with permanent prosthetic constructions 8-12 weeks after implant surgery. RESULTS: Ten (47.6%) implants were inserted in residual bone of 2.6-4.9 mm and 11 (52.3%) implants were inserted in residual bone of 5-8.9 mm. No implants were lost after surgery and follow-up. There was no marginal bone loss during the follow-up verified by CBCT. The implants penetrated on average 4.4 mm (SD 2.1 mm) into the sinus cavity and the mean bone gain was 3 mm (SD 2.1 mm). CONCLUSION: Flapless transalveolar sinus lift procedures visually guided by preoperative CBCT can successfully be used to enable placement, successful healing and loading of one to three implants in residual bone height of 2.6-8.9 mm. There was no marginal bone loss during the 3-12 months follow-up.

Guided bone generation in a rabbit mandible model after periosteal expansion with an osmotic tissue expander.

OBJECTIVES: To evaluate the space-maintaining capacity of titanium mesh covered by a collagen membrane after soft tissue expansion on the lateral border of the mandible in rabbits, and to assess bone quantity and quality using autogenous particulate bone or bone-substitute (Bio-Oss(®) ), and if soft tissue ingrowth can be avoided by covering the mesh with a collagen membrane. MATERIAL AND METHODS: In 11 rabbits, a self-inflatable soft tissue expander was placed under the lateral mandibular periosteum via an extra-oral approach. After 2 weeks, the expanders were removed and a particulated onlay bone graft and deproteinized bovine bone mineral (DBBM) (Bio-Oss(®) ) were placed in the expanded area and covered by a titanium mesh. The bone and DBBM were separated in two compartments under the mesh with a collagen membrane in between. The mesh was then covered with a collagen membrane. After 3 months, the animals were sacrificed and specimens were collected for histology. RESULTS: The osmotic soft tissue expander created a subperiosteal pocket and a ridge of new bone formed at the edges of the expanded periosteum in all sites. After the healing period of 3 months, no soft tissue dehiscence was recorded. The mean bone fill was 58.1±18% in the bone grafted area and 56.9±13.7% in the DBBM area. There was no significant difference between the autologous bone graft and the DDBM under the titanium mesh with regard to the total bone area or the mineralized bone area. Scanning electron microscopy showed that new bone was growing in direct contact with the DBBM particles and the titanium mesh. There is a soft tissue ingrowth even after soft tissue expansion and protection of the titanium mesh with a collagen membrane. CONCLUSION: This study confirms that an osmotic soft tissue expander creates a surplus of periosteum and soft tissue, and that new bone can subsequently be generated under a titanium mesh with the use of an autologous bone graft or DBBM.

Super-EBA and IRM as root-end fillings in periapical surgery with ultrasonic preparation: a prospective randomized clinical study of 206 consecutive teeth.

OBJECTIVE: This study evaluated the treatment outcome after periapical surgery with the use of 2 different retrograde root-filling materials and the influence of 3 pre- and perioperative variables on the periapical healing. STUDY DESIGN: Two hundred six teeth in 164 patients were randomly allocated to receive either IRM or Super-EBA as a retrograde root-end seal. The teeth were reviewed 12 months after surgery. The influence of lesion size, lesion type, and orthograde root filling quality on healing was analyzed. RESULTS: One hundred ninety-four teeth in 153 patients were reviewed. Radiologic evaluation and clinical examination revealed 91% success rate for the IRM group and 82% for the Super-EBA group. There was no statistical significance in the healing outcome between the 2 groups (Fisher exact test). The analyzed pre- and perioperative variables had no significant influence on the treatment outcome (Z test). CONCLUSIONS: Both retrograde materials tested in this study can serve as a root-end seal in periapical infected teeth, according to the results of the healing outcome after 12 months' follow-up.

Frontal bone and modified zygomatic implants for retention of a nasal prosthesis: Surgical planning using a three-dimensional computer software program.

Implants integrated into bone have revolutionised the retention of total nasal prostheses. However, it may be difficult to identify available sites for placement of the implant after excision. In addition, it is ideal to minimise wide bony exposure after radiotherapy to avoid compromising the blood supply. In this paper we describe a technique for accurate placement of frontal bone and customised zygomatic implants using a computer-designed and fabricated surgical guide with a minimal access flap.

Onlay bone grafting of the mandible after periosteal expansion with an osmotic tissue expander: an experimental study in rabbits.

OBJECTIVES: To evaluate the space-maintaining capacity of a titanium mesh or a bioresorbable mesh after periosteal expansion and to assess bone formation under a titanium mesh or a bioresorbable mesh on the lateral border of the mandible by qualitative and quantitative histological analysis. MATERIAL AND METHODS: In 13 rabbits, a self-inflatable soft tissue expander was placed intraorally, bilaterally under the mandibular periosteum via an extra oral approach. After 2 weeks, the expanders were removed and a particulated onlay bone graft was placed and covered by a titanium mesh or a bioresorbable mesh. After 3 months, the animals were sacrificed and specimens were collected for histology. RESULTS: The osmotic soft tissue expander created a subperiosteal pocket and a ridge of new bone had formed at the edges of the expanded periosteum in all sites. After the healing period of 3 months, soft tissue dehiscence was recorded in two of the sites with bioresorbable meshes. The mean bone fill was 65% under the titanium mesh and 85% under the bioresorbable mesh (P<0.05). There was no significant difference between the titanium mesh and the bioresorbable mesh regarding the height of the meshes, mesh area and mineralized bone area. Scanning electron microscopy shows that new bone is growing in direct contact with the resorbable mesh and the titanium mesh. CONCLUSION: This study confirms that an osmotic soft tissue expander creates a surplus of periosteum and soft tissue and that new bone can be generated under a titanium mesh or bioresorbable mesh.

Maxillary sinus floor augmentation and simultaneous implant placement using locally harvested autogenous bone chips and bone debris: a prospective clinical study.

PURPOSE: The aim of this study was to prospectively evaluate the status of implants, marginal bone loss, and outcome of maxillary sinus floor augmentation in patients undergoing maxillary sinus lift and simultaneous implant placement with the use of bone grafts harvested adjacent to the actual surgical site. MATERIALS AND METHODS: Patients in need of maxillary sinus floor augmentation to enable implant placement were enrolled in 2 different groups. In group A, a "bone trap" was used to harvest bone debris during implant preparation with additional bone collected by further drilling adjacent to the implant sites. In group B, a "bone scraper" was used to harvest cortical bone chips from the zygomatic buttress and from the lateral sinus wall before opening of a bony window. All patients were provided a fixed partial denture after a healing period of 3 to 6 months. A total of 61 patients with 81 Straumann implants (Institut Straumann AG, Basel, Switzerland) were assessed, with 17 patients (20 implants) in group A and 44 patients (61 implants) in group B. RESULTS: One implant was lost (in group B) before loading. The survival rate after a follow-up of 12 to 60 months was 98.8%. There was no significant difference in marginal bone loss on the mesial and distal sides of the implant when baseline to 1-year registration was compared with baseline to final registration. During the same time, graft height decreased significantly on the distal apical side of the implants. CONCLUSIONS: Bone grafts can be locally harvested at the site of the maxillary sinus augmentation procedure to enable placement, successful healing, and loading of 1 to 3 implants.

Periapical surgery using ultrasonic preparation and thermoplasticized gutta-percha with AH Plus sealer or IRM as retrograde root-end fillings in 160 consecutive teeth: a prospective randomized clinical study.

OBJECTIVE: The aim of this study was to evaluate the healing outcome after periapical surgery with an ultrasonic cleaning technique in conjunction with the use of either of 2 different retrograde root-filling materials in teeth with apical periodontitis. STUDY DESIGN: One hundred sixty teeth in 139 consecutive patients were randomly allocated into 2 groups receiving either IRM or thermoplasticized gutta-percha (GP) with AH Plus sealer as a retrograde root-end seal. The patients were reviewed 12 months after surgery. The results were analyzed with Fisher exact test. RESULTS: One hundred forty-seven teeth in 131 patients were reviewed. Radiologic evaluation and clinical examination showed an 85% success rate for the IRM group and 90% for GP group. There was no statistical significance between the 2 groups. CONCLUSION: Both tested materials, IRM and GP, are suitable as retrograde root-end filling materials in conjunction with ultrasonic root-end preparation according to the results of the healing outcome after 12 months follow-up.

Oral health and oral implant status in edentulous patients with implant-supported dental prostheses who are receiving long-term nursing care.

AIM: The aim of this study was to investigate oral health and oral implant status in a group of edentulous patients receiving long-term residential or nursing care (LTC), all of whom had implant-supported fixed or removable dental prostheses. MATERIAL AND METHODS: A dental examination was performed on a total of 3310 patients receiving LTC and from this population 35 edentulous patients in whom dental implants had been placed formed the cohort for this study. All examinations were performed by a specialist in hospital dentistry and took place in the patients' own home environment. Oral health was assessed by means of a protocol which evaluated oral hygiene status, possible oral mucosal inflammation and oral mucosal friction levels. Any problems with the implant-supported prosthesis, implant mobility or other complications were also assessed. In addition, patients were asked about any oral symptoms and their usual oral hygiene procedures. RESULTS: About half of the subjects (17/35) were registered as having no/mild inflammation with 18 of 35 having moderate/severe inflammation. Twelve of the 35 patients had good/acceptable oral hygiene and 23 of 35 had poor/bad oral hygiene. Twenty-one of the 35 patients depended on help from the nursing personnel for their daily oral hygiene procedures. Obvious problems with food impaction were noted in 11 patients. A total of 229 implants had been placed in 43 jaws supporting 40 full arch-fixed prostheses and three implant-borne overdentures. There was no evidence of mobility or fractures of either the implants or the prostheses. Fifteen implants showed some exposed screw threads. Pus was exuding from one implant site and general peri-implant gingival hyperplasia was noted in two patients. Twenty-four patients were completely satisfied with the function and appearance of their implant-supported prostheses. Two patients were totally dissatisfied. CONCLUSION: This study indicates that oral implant therapy can be considered as a treatment of choice in elderly patients, even if oral hygiene is sub-optimal.

Periosteal expansion of rabbit mandible with an osmotic self-inflatable expander.

We aimed to evaluate a new technique for intraoral expansion of soft tissue with a self-inflatable expander in rabbits. We placed a self-inflatable soft tissue expander bilaterally in eight rabbits under the periosteum of the mandible through an extraoral approach. The expander was left to self-inflate for two weeks, after which the animals were killed and specimens collected for histological examination. The self-inflatable soft tissue expanders expanded the periosteum. There were no dehiscences or infections. Histological observations showed no signs of any inflammatory reaction and there was no evidence of bony resorption. New bone had formed at the edges of the expanded periosteum. In the control area no new bone had formed. The osmotic soft tissue expander model for intraoral soft tissue and periosteal expansion suggests a promising way of creating a surplus of soft tissue that can be used to cover bone grafts.

The use of particulate bone grafts from the mandible for maxillary sinus floor augmentation before placement of surface-modified implants: results from bone grafting to delivery of the final fixed prosthesis.

PURPOSE: This prospective study followed 61 patients who were partially dentulous and considered to have insufficient bone volume for routine implant treatment and consequently underwent sinus inlay bone grafting. PATIENTS AND METHODS: The patients were treated with maxillary sinus floor augmentation with particulated autogenous bone from the mandibular ramus/corpus. After a healing period, dental implants (n = 180) were installed. RESULTS: Radiographic examination revealed average residual vertical bone heights of 6.5 mm in the first premolar region, 3.8 mm in the second premolar region, 3.5 mm in the first molar region, and 2.6 mm in the second molar region. The average implant lengths were 12 mm in the first premolar region and 11 mm in the second premolar, first, and second molar regions. All patients received a fixed partial prosthesis. All bone grafts were stable, and the implant survival rate was 98.9%. There were few cases of minor complications postoperatively and no record of any injured teeth, heavy bruising, bleeding, or swelling in either the donor site or the recipient site. The present clinical study demonstrated a low failure rate of surface-modified dental implants when placed into the maxillary sinus an average of 7 months after augmentation with particulate mandibular bone grafts and followed up to delivery of the final fixed prosthesis. CONCLUSION: The findings indicate that treatment with endosseous implants may be as predictable in patients with inadequate bone who underwent sinus floor augmentation as in patients with adequate bone volume.

Transverse displacement of the proximal segment after bilateral sagittal osteotomy: a comparison of lag screw fixation versus miniplates with monocortical screw technique.

PURPOSE: The purpose of the present study was to compare lag screw fixation versus miniplates with monocortical screw technique with respect to the amount of transverse displacement of the proximal segment after bilateral sagittal osteotomy (BSO) for mandibular advancement surgery. PATIENTS AND METHODS: We conducted a multicenter, retrospective investigation of 82 patients who underwent a mandibular advancement with BSO and rigid internal fixation. Forty-five patients from Denmark and Sweden, the miniplate fixation group, received a rigid fixation consisting of miniplates with monocortical screws. Thirty-seven patients from the Mayo Clinic, the lag screw fixation group, received a rigid fixation with lag screw fixation of the mandible. The transverse displacement and angulation of the proximal segments were measured on posterior-anterior cephalometric radiographs, using the best-fit method. RESULTS: After BSO, 44 of 45 patients in the miniplate fixation group showed an increased transverse intergonion distance with a mean of 5.0 mm and an increase transverse interramus width with a mean of 2.4 mm. Thirty-six of 37 patients in the lag screw fixation group had an increased intergonial width with a mean of 5.6 mm, and 35 of 37 patients showed an increased transverse interramus width with a mean of 3.3 mm. t tests showed that there were no significant differences between the 2 groups with respect to these 2 variables. CONCLUSIONS: Our results indicate that transverse displacements of the proximal segments occur after BSO surgery with both miniplate or lag screw fixation technique. Attention and future studies should focus on possible complications that transverse displacement of the proximal segment may cause.

A prospective multicenter study using two different surgical approaches in the mandible with turned Brånemark implants: conventional loading using fixed prostheses.

BACKGROUND: The use of a submerged implant system in a nonsubmerged surgical procedure has been reported to have promising results. At the time this study was initiated, no prospective, comparative studies with randomization between submerged and nonsubmerged surgical techniques had been published. PURPOSE: To evaluate the submerged and nonsubmerged surgical techniques when treating mandibular edentulism using a submerged implant system, with regard to implant survival and complications. MATERIALS AND METHODS: A total of 77 patients were included and treated at nine clinics in Sweden and Norway. In total, 404 Brånemark System implants (standard and MkII implants) were inserted in the edentulous mandible; 198 implants according to the nonsubmerged protocol and 206 implants according to the traditional submerged procedure. The follow-up period was up to 36 months after prosthesis insertion. RESULTS: In the nonsubmerged group, 17 implants out of 198 implants (8.6%) were lost and in the submerged group, 5 out of 206 implants (2.4%) were lost. All implant failures occurred before the delivery of the final prosthesis. No major complications were reported during the implant surgery. However, at the clinical check-up postoperatively and at the abutment connection surgery, 6 patients in the nonsubmerged group complained of pain at the implant sites, whereas there were no complaints of pain in the submerged group. CONCLUSIONS: The results of this study suggest that a turned Brånemark implant designed for a submerged implant placement procedure can be used in a nonsubmerged procedure and may be as predictable as the conventional submerged approach.