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PubMed2000

An in vitro study of the effect of bony buttressing on fixation strength of a fractured atrophic edentulous mandible model.

PURPOSE: The purpose of this study was to measure the resistance to displacement in an adult bovine rib mandible model as the vertical dimension of the bone decreases, and to compare the fixation strength of titanium miniplates and reconstruction plates. MATERIALS AND METHODS: Five groups of 6 ribs each were tested based on the vertical dimension of the rib and method of fixation (group 1, 40 mm, miniplate), (group 2, 30 mm, miniplate), (group 3, 20 mm, miniplate), (group 4, 10 mm, miniplate), (group 5, 10 mm, reconstruction plate). In the 4 groups stabilized with a miniplate, a 3-hole-per-segment, 2.0-mm titanium miniplate and 6.0-mm monocortical titanium screws were used. In group 5, a 3-screw-per-segment, 2.4-mm titanium reconstruction plate and 2.4-mm bicortical titanium screws were used for fixation. A 2-dimensional beam model (Class III lever) was established, and an Instron machine was used initially to develop a load-displacement curve to 100 N for each specimen. An osteotomy was then created, and the segments were reduced without preload. The ribs were then loaded to failure in the Instron machine. The load-displacement curve and failure load were recorded. RESULTS: There was no significant difference (P < or = .05) between any of the groups before the osteotomy. At 75 N, groups 1 and 2 were superior to group 5 in resistance to displacement. Group 4 showed significantly less (P < or = .05) resistance to displacement than the other experimental miniplated subgroups. As loads increased, groups 1 and 2 continued to show increased resistance to displacement when compared with groups 3, 4, and 5. Loads to failure for groups 1 and 2 were comparable to group 5. CONCLUSIONS: Decreased resistance to displacement occurs with decreasing vertical dimension of the bovine rib. In fractures of the edentulous mandible, a miniplate is more likely to provide adequate fixation if the mandible is 30 to 40 mm in height (nonatrophic). At higher loads, groups with greater vertical height (30 mm and 40 mm) provided resistance to displacement equivalent to the 10-mm group repaired with a reconstruction plate. Therefore, fractures of the atrophic mandible may be better treated with more rigid techniques.

Alveolar Bone Loss↗
PubMed1978

Experimental fractures of monkey mandibles.

Forty vervet monkey half mandibles, 20 with unerupted third molars and 20 with erupted third molars, were partially embedded in acrylic and loaded in an Instron tensiometer. Mandibles with unerupted third molars fractured at 15.8 +/- 2.5 kg while those having erupted third molars fractured at 26.4 +/- 4.2 kg. Mandibles having unerupted third molars were shown to be significantly weaker than the mandibles with erupted third molar (t = 8.45, P less than 0.001).

Animals↗
PubMed1998

Pathological fractures of the mandible. A review of the etiology and treatment.

A retrospective study was undertaken to analyse the etiology, site and treatment procedures of 30 pathological fractures of the mandible. Fifty percent of the fractures had an inflammatory cause. The remaining cases were associated with severe atrophy of edentulous mandibles (4), benign tumours (3), cysts (3), and primary or secondary malignancies (5). Regardless of the cause, the majority of the fractures occurred in the body of the mandible. Pathological fractures of the mandible most often have to be treated by eliminating the cause of the underlying condition while immobilizing the fragments either with osteosynthesis or archbars and intermaxillary fixation.

Adult↗
PubMed1995

Hyperbaric oxygen treatment of osteoradionecrosis of the mandible. Experience in 29 patients.

In recent years hyperbaric oxygen has gained an important role in the treatment of osteoradionecrosis of the mandible. In the treatment of 29 patients with osteoradionecrosis of the mandible, a combination of surgical debridement, antibiotics, and hyperbaric oxygen was used in 27 cases. In 20 of the 29 patients the osteoradionecrosis was considered to be resolved after treatment. In 31% of the patients, the continuity of the mandible was lost. It was concluded that combined treatment of surgical debridement, antibiotics, and hyperbaric oxygen gives acceptable results and may, when used in an early phase of the disease, limit the number of patients who lose continuity of the mandible.

Adult↗
PubMed1994

Augmentation of the rat mandible using guided tissue regeneration.

The aim of the present study was to investigate whether it is possible to increase the height of the rat mandible at its inferior border using a bioresorbable membrane adapted to create a secluded space for ingrowth of bone tissue. The experiment was carried out in 18 rats. The mandibular ramus was exposed at both sides. A standardized titanium microimplant was then inserted in the naturally existing curvature at the inferior border of the mandible, serving as a fixed reference and space maker. The mandibular border on one side was covered with a polyhydroxybutyrate bioresorbable membrane, and the contralateral side, serving as control, received no membrane before closure of the wound. The membranes were placed in such a way that a space was created in the curvature between the membrane and the inferior border of the mandible. Macerated jaw specimens representing 6 months of healing demonstrated substantial amounts of bone formation in the curvature of the inferior border of the mandible, resulting in a flattening of the inferior border. Negligible amounts of bone formation had occurred in the control sides. Histological analysis demonstrated that, in 4 of 6 experimental specimens, the space created by the membrane was completely filled with new bone after 6 months of healing, but in some specimens soft tissue seemed to have migrated into the space through ruptures of the membrane or because of poor membrane adaptation at its lateral borders, thereby inhibiting bone formation. Only negligible bone formation had occurred at the control sides.(ABSTRACT TRUNCATED AT 250 WORDS)

Alveolar Bone Loss↗
PubMed2002

Lymphangioma involving the mandible: immunohistochemical expressions for the lymphatic proliferation.

We report a case of lymphangioma involving oral mucosa and mandible of an elderly female. The surgical and radiological examinations indicated that the lymphangioma was mainly distributed in the labial mucosa tissue, but had gradually extended into the periosteum and intrabony space of mandible. Immunohistochemical staining was also performed using antiseras of alpha-smooth muscle actin (alpha-SMA), von Willebrand factor (vWF), angiogenin, vascular endothelial growth factor (VEGF), and proliferating cell nuclear antigen (PCNA) to elucidate the pathogenetic implications of the intraosseous lymphangioma. The present case of lymphangioma showed strong immunohistochemical reactivity of angiogenin and vWF, while it showed weak reactions of VEGF and PCNA. The immunostaining of alpha-SMA disclosed an abnormally thinned and discontinuous smooth muscle layer in the lymphatics. Both the X-rays and histological examination showed that the lymphangioma lesion was gradually extending into the adjacent osteoporotic marrow space of mandible. Therefore, we believe that the present case of intraosseous lymphangioma, which showed the harmatomatous growth of the lymphatics into the marrow space of mandible, is closely related to osteoporotic changes of old age.

Actins↗
PubMed2000

Nonunion of the mandible: an analysis of contributing factors.

PURPOSE: The aim of this study was to review our experience of nonunion of mandible fractures and to compare this information with the past and present literature. The analysis also evaluated risk factors and those conditions that lead to nonunion so that the complication may be better managed and possible avoided. PATIENTS AND METHODS: A retrospective review of mandible fractures in a major medical center was carried out on patients treated from 1994 through 1998. The nonunion cases were evaluated for factors such as age, sex, race, cause of fracture, location of fracture, delay until the patient obtained treatment, teeth in the fracture line, use of antibiotics, multiplicity of fractures, degree of fragmentation, medical problems, and drug and alcohol abuse. The adequacy of reduction and appropriateness of the fixation techniques were evaluated by analysis of the postoperative imaging studies. Postoperative occlusion and patient compliance were also included in the evaluation. RESULTS: Of the 906 patients with 1,432 mandible fractures, there were 25 nonunion complications, for an incidence of 2.8%. Most patients with nonunion were men who had received the fracture as a result of an altercation. The nonunion was frequently noted in the body, and was almost twice as common (39% vs 17.6%) in patients with multiple fractures than in a randomly selected group who did not have the complication. Delayed treatment was noted in 8 of the patients, and teeth were present in the fracture line in another 8. Alcohol and drug abuse were prevalent, and 1 of 5 of the patients removed their fixation devices. Eight patients were believed to be stabilized inadequately, and 1 patient also had a poor reduction. Osteomyelitis was a common complication. CONCLUSIONS: The incidence of nonunion appears to be unchanged over time regardless of the varied and presumably advanced methods of fixation and reduction. Multiple fractures were a contributory factor, and the body of the mandible appeared to be a common site. Many patients had osteomyelitis associated with the nonunion. Inadequate stabilization or reduction were important causes. Other suspected contributory factors included failure to provide antibiotics, delay in treatment, teeth in the fracture line, alcohol and drug abuse, inexperience of the surgeon, and lack of patient compliance.

Adult↗
PubMed2002

Disarticulation resections of the mandible: a prospective review of 16 cases.

PURPOSE: This article provides a review of the disarticulation resection of the mandible for various benign and malignant tumors and non-neoplastic processes. In so doing, the author proposes a classification to describe extension of pathology into the condylar region, thereby requiring its sacrifice. Recommendations are also proposed for preservation versus sacrifice of the meniscus when performing a disarticulation resection of the mandible. Finally, complications are evaluated in this type of mandibular resection. PATIENTS AND METHODS: This review is based on the author's accumulated clinical data obtained from performing disarticulation resections on 16 patients who presented with 10 different pathologic diagnoses. Disarticulation resections are performed for 3 different patterns of extension of pathologic processes into the condylar region, designated as type I, type II, and type III by the author. These designations reflect the radiographic involvement of the condyle or subcondylar region of the mandible by the pathologic entity. The designations of type II and type III extensions are diagnosis dependent, whereas type I extension is independent of diagnosis. RESULTS: Five patients in this series presented with type I condylar extension, 2 patients presented with type II condylar extension, and 9 patients presented with type III condylar extension. The meniscus required sacrifice in 3 of the 16 patients. Complications occurred in 3 of 16 patients and included 1 dislocation of the plate into the middle cranial fossa, 1 dislocation of the plate inferiorly and posteriorly to the mastoid process, and 1 cutaneous exposure of the plate. CONCLUSIONS: Disarticulation resections are rarely required variants of segmental resection of the mandible, and they are required by a variety of pathologic processes of the jaws and contiguous structures. The placement of a reconstruction bone plate with an affixed condylar prosthesis is well tolerated by patients and is associated with few complications. These reconstruction bone plates favorably support facial form, symmetry, and occlusion such that many patients delay their definitive bony reconstruction. Because these condyles are temporary prostheses, the surgeon should consider their removal with bony reconstruction of the disarticulation defect as soon as possible after the ablative surgery.

Bone Plates↗
PubMed2003

Central mucoepidermoid carcinoma of the mandible: report of four cases with long-term follow-up.

Central mucoepidermoid carcinomas are uncommon tumours, representing about 2 to 4% of all mucoepidermoid carcinomas. They are histologically low-grade cancers, usually affecting the mandible as uni- or multilocular radiographic lesions. The authors report four cases of central mucoepidermoid carcinomas affecting the mandible and discuss their clinical, radiographic and histological findings. Four females were affected, with a mean age of 42 years and all cases involved the posterior mandible. Treatment included surgery in three cases and surgery associated to neck dissection and radiotherapy in one case. Two patients showed no recurrence and were alive without signs of the disease after a mean follow-up of 78 months. The other two patients showed local recurrence and one was alive with disease after a follow-up of 384 months, and the other was followed-up for 324 months dying by other causes without signs of the tumour. Central mucoepidermoid carcinomas of the mandible are low-grade tumours, and effective surgical treatment involving wide local excision or en bloc resection allows patients to have a favourable prognosis after long-term follow-up.

Adult↗
PubMed2005

Operative time analysis of miniplate fixation of the mandible.

Our purpose in this study was to report and compare operating room times for the various methods of mandible fracture repair. We describe a methodology of treatment in selected patients, using efficient repair techniques; namely, miniplate fixation with four-screw mandibular occlusion. We report our outcomes in successful healing, occlusion, complications, and operating times. A retrospective chart review was performed of 68 patients suffering mandible fractures treated by various surgeons at a single institution. Miniplate fixation technique requires significantly less time in the operating room than other mandible repair techniques, including mandibulomaxillary fixation. Miniplate fixation technique is both an efficacious and an efficient means of repairing certain mandible fractures.

Bone Plates↗
PubMed2003

Transoral versus extraoral reduction of mandible fractures: a comparison of complication rates and other factors.

OBJECTIVE: This retrospective study evaluates results and complications of the transoral and extraoral approaches for open reduction and internal fixation of mandibular body, angle, and ramus fractures. Our aim was to describe advantages and disadvantages of the techniques and to develop criteria for choosing between surgical approaches. STUDY DESIGN AND SETTING: A retrospective chart review was performed on patients with mandible fractures occurring between August 1999 and October 2001 at a level I trauma center. Only mandibular body, angle, and ramus fractures requiring open reduction were selected for this study. Cases were evaluated for cause, age, gender, dentition, site and extent of fractures, surgical approach, postoperative complications, operative time, and postoperative occlusion. RESULTS: Of the 227 patients with mandibular fractures, 78 had body, angle, or ramus fractures requiring open reduction. Of these, 36 were treated extraorally, and 42 were treated transorally. Criteria for selecting one procedure over another often involved training and surgeon experience and those factors normally considered important in defining the difficulty of treatment and prognosis of the patient. Seven of the 42 patients were converted from a transoral to an extraoral approach because of inadequate exposure. Similar complication rates occurred for the transoral and extraoral approaches, but because of the time required for converting from the transoral to extraoral approach, the average operative time was found to be increased in patients undergoing the transoral approach. CONCLUSION AND SIGNIFICANCE: Decisions regarding treatment approaches for open reduction of mandible fractures often relate to surgeon experience and training, modified by factors that can affect uncomplicated healing such as fracture locations and displacement, comminution of the fracture, infection, dentition, and atrophic changes of the mandible. In some cases, the choice is affected by availability of equipment and experience of operating room personnel. More difficult cases involving an edentulous, atrophic mandible or comminution should be considered for extraoral exposure.

Adolescent↗
PubMed2002

A 3-dimensional finite-element analysis investigating the biomechanical behavior of the mandible and plate osteosynthesis in cases of fractures of the condylar process.

OBJECTIVE: The condylar region is one of the most frequent sites for mandibular fractures, with direct application of miniplates being the most commonly used open-fixation technique today. Yet, anatomic and biomechanical limitations continue to make this application technically challenging with a considerable complication rate. We sought to analyze such incongruencies with respect to the complex biomechanical behavior of the mandible. STUDY DESIGN: Individual human mandible geometry, the specific bone density distribution, and the position and orientation of the masticatory muscles were evaluated by performing computed tomography scans and a sequential dissection of the cadaver mandible. Three-dimensional finite-element analysis was performed for different fracture sites, osteosynthesis plates, and loading conditions. RESULTS: Osteosynthesis of fractures of the condylar neck with 1 or 2 miniplates of a diameter of 2.35 x 1.00 mm was found to be an insufficient fixation method. This also applies for plates (3.60 x 1.54 mm), according to Pape et al,(8) when used in singular fashion (high condylar neck fractures excepted). In cases of singular occlusal contacts in the molar region (particularly at the contralateral side of the fracture), the highest stress values inside the mandible and osteosynthetic devices could be observed. With even the static yield limit of titanium being exceeded in such cases, consecutive rapid failure of the miniplates becomes most likely when loading of the condylar region caused by bite forces cannot be prevented. CONCLUSION: We strongly recommend the use, whenever possible, of 2 plates in the manner described by Pape et al(8) for osteosynthesis of fractures of the condylar neck in combination with bicortically placed screws. The stiffness of a singular osteosynthesis plate made of titanium in a diametrical dimension of approximately 5.0 x 1.75 mm was found to be equivalent to the physiological bone stiffness in the investigated fracture sites. The actual stiffness of such a fixation plate is approximately 3 times higher than the stiffness of devices commonly in use.

Bite Force↗
PubMed2002

Effects of headgear Herbst and mandibular step-by-step advancement versus conventional Herbst appliance and maximal jumping of the mandible.

The aims of this study were to compare dental and skeletal treatment changes in Class II division 1 malocclusions with two modes of maxillary control and two modes of bite-jumping. The subjects comprised Chinese children with severe Class II division 1 malocclusions, i.e. 21 consecutive subjects (13.4 +/- 1.4 years) treated with a headgear Herbst appliance and step-by-step advancement (HHSSA) of the mandible, and 24 consecutive subjects (13.2 +/- 1.4 years) treated with a 'conventional' Herbst appliance with maximal jumping (HMJ) of the mandible. Lateral cephalograms obtained at the start and end of treatment were analysed. The results showed that the improvement of the sagittal jaw relationship was significantly larger (2.9 mm; P < 0.001) in the HHSSA group than in the HMJ group due to the increased effect on the maxilla (-1.5 mm, P < 0.001) and the mandible (+1.4 mm, NS). There was no significant difference in the change in lower anterior face height, being 2.7 and 3.1 mm, respectively. The mandibular plane angle decreased significantly in the HHSSA group (-0.7 degree; P < 0.05) and increased insignificantly in the HMJ group (0.4 degree, NS), the difference being statistically significant (P < 0.01). The maxillary molars moved significantly more distally (1.1 mm, P < 0.05) and were intruded in the HHSSA group (-1.0 mm, P < 0.001) compared with a small extrusion in the HMJ group (+0.3 mm, NS), the difference being statistically significant (P < 0.001). There was no significant difference in the effect on the mandibular teeth. Treatment with HHSSA seems to result in a greater effect on the sagittal jaw relationship, improved vertical control and more maxillary molar movement. Mandibular anchorage loss was not reduced with step-by-step advancement of the mandible.

Adolescent↗
PubMed2001

Repair of a critical size defect in the rat mandible using allogenic type I collagen.

Mandibular fractures, resulting from either trauma or reconstructive surgery, can be challenging craniofacial problems. The morbidity of failed fracture healing is significant and may require bone grafting. Donor site morbidity and finite amounts of autogenous bone are major drawbacks of autogenous bone grafting. Similarly, the use of allografts and xenografts may be associated with an increased risk of rejection, infection, and nonunion. To circumvent the limitations of bone grafting, research efforts have focused on formulating a suitable bone substitute. The purpose of our study was to evaluate the efficacy of type I collagen implants in repairing critical sized mandibular defects in rats. Twelve male Sprague-Dawley rats (200-300g) were divided equally into control and experimental groups. Full thickness, round, four millimeter in diameter defects were created in the ramus of the right mandible of all rats using an electrical burr at low speed. The defects were irrigated of all bone chips, and either filled with a precisely fitted disk of allogenic collagen type I gel (experimental animals) or left empty (control animals). Animals were killed 6 weeks after surgery and healing of the bone defects was assessed in a blinded fashion using radiologic and histologic analysis. Radiologic analysis of the control group revealed a clear circular right mandibular defect in all animals, whereas the collagen disk implant group revealed an indistinct to nonexistent right mandibular defect in all animals. Densitometric analysis revealed a significant difference between these groups (* P = 0.01). Similarly, gross analysis of control mandibles revealed a 4mm round, soft-tissue filled defect, while implanted defects demonstrated gross bone spanning the defect. Finally, histologic analysis of all control mandibles revealed clearly demarcated bony edges at the defect border with connective tissue spanning the defect. In contrast, histological analysis of all implanted mandibles revealed indistinct bony edges at the defect border with a thin layer of osteoblasts and viable bone spanning the defects. We have demonstrated the ability of type I collagen to promote healing of a membranous bony defect that would not otherwise heal at 6 weeks. The suitability of type I collagen as a carrier matrix provides ample opportunity for tissue-engineered approaches to further facilitate bony defect healing. Promoting bone formation through tissue engineering matrices offers great promise for skeletal healing and reconstruction.

Absorptiometry, Photon↗
PubMed1998

Fibula osteoseptocutaneous flap for reconstruction of osteoradionecrosis of the mandible.

Osteoradionecrosis of the mandible poses formidable problems for treatment. In the last 6 years, the fibula osteoseptocutaneous free flap was used in 12 cases to replace mandibles with radionecrotic damage. The presence of a pathologic fracture, exposed necrotic bone, or a persistent fistula not responding to conservative treatment were the indications for such a radical approach. Mandible defects after resection were around 8.0 cm long, and in all cases intraoral mucosa, skin, or both were included with the bone excision. All vascularized fibula osteoseptocutaneous flaps transplanted were successful with good primary bone healing. Adequate facial symmetry and improvement in oral function was achieved. No evidence of osteoradionecrosis recurrence was observed after a mean follow-up period of 3 years and 9 months. The advantages of using the fibula osteoseptocutaneous flap for mandible reconstruction are numerous, and good aesthetic and functional results can be obtained when it is used for reconstruction after radical excision of osteoradionecrotic lesions.

Adult↗
PubMed1999

Evaluation of bone height in osseous free flap mandible reconstruction: an indirect measure of bone mass.

Osseous free flaps have become the preferred method of mandibular reconstruction after oncologic surgical ablation. To elucidate the long-term effects of free flap mandibular reconstruction on bone mass, maintenance or reduction in bone height over time was used as an indirect measure of preservation or loss in bone mass. Factors potentially influencing bone mass preservation were evaluated; these included site of reconstruction (central, body, ramus), patient age, length of follow-up, adjuvant radiotherapy, and the delayed placement of osseointegrated dental implants. A retrospective analysis of patients undergoing osseous free flap mandible reconstruction for oncologic surgical defects between 1987 and 1995 was performed. Postoperative Panorex examinations were used to evaluate bone height and bony union after osteotomy. Fixation hardware was used as a reference to eliminate magnification as a possible source of error in measurement. There were 48 patients who qualified for this study by having at least 24 months of follow-up. There were 27 male and 21 female patients, with a mean age of 45 years (range, 5 to 75 years). Mandibular defects were anterior (24) and lateral (24). Osseous donor sites included the fibula (35), radius (6), scapula (4), and ilium (3). There were between zero and four segmental osteotomies per patient (excluding the ends of the graft). Nineteen percent of all patients had delayed placement of osseointegrated dental implants. Initial Panorex examinations were taken between 1 and 9 months postoperatively (mean, 2 months). Follow-up Panorex examinations were taken 24 to 104 months postoperatively (mean, 47 months). The bony union rate after osteotomy was 97 percent. Bone height measurements were compared by site and type of reconstruction. The mean loss in fibula height by site of reconstruction was 2 percent in central segments, 7 percent in body segments, and 5 percent in ramus segments. The mean loss in bone height after radial free flap mandible reconstruction was 33 percent in central segments and 37 percent in body segments; ramus segments did not lose height. The central and body segments reconstructed with scapular free flaps did not lose height, but one ramus segment lost 20 percent of height. There was no loss in bone height in mandibular body reconstruction with the ilium free flap. Fibula free flaps did not significantly lose bone height when evaluated with respect to age, follow-up, radiation therapy, or dental implant placement. The retention in bone height demonstrated in this study suggests that bone mass is preserved after osseous free flap mandible reconstruction. The greatest amount of bone loss was seen after multiply osteotomized radial free flaps were used for central mandibular reconstruction. The ability of the fibula free flap to maintain mass over time, coupled with its known advantages, further supports its use as the "work horse" donor site for mandible reconstruction.

Adolescent↗
PubMed2005

Osteoblastic osteosarcoma of the mandible: findings on Tc-99m HMDP bone and Ga-67 citrate scintigraphy.

A 25-year-old woman presented with a disturbance in the opening of her mouth 5 months before admission. On admission, painful swelling of the right preauricular region was revealed. Computed tomography (CT) demonstrated a soft tissue density mass around the right condylar process of the mandible. Tc-99m hydroxymethylene diphosphonate (HMDP) bone scintigraphy and Ga-67 citrate scintigraphy showed avid uptake in the mass. The tumor was histologically identified as an osteoblastic osteosarcoma of the right mandible. There are few reports of Ga-67 citrate scintigraphy findings of osteoblastic osteosarcoma of the mandible. The accumulation patterns on Tc-99m HMDP bone scintigraphy and Ga-67 citrate scintigraphy are possibly characteristic of osteoblastic osteosarcoma of the mandible.

Adult↗
PubMed2004

Early function of splinted implants in maxillas and posterior mandibles, using Brånemark System Tiunite implants: an 18-month prospective clinical multicenter study.

BACKGROUND: Immediate or early loading of implants placed in maxillas and posterior mandibles has been a concern as bone density is often low in these areas, making it difficult to establish good initial implant stability. By adapting implant design and insertion protocols, however, high initial implant stability may be achieved in these regions. Further, a modified implant surface texture has been proved to help in maintaining stability during the initial healing period. PURPOSE: The aim of the present study was to investigate the clinical performance of oxidized titanium implants (TiUnite, Nobel Biocare AB, Gothenburg, Sweden) when used for early function in the maxilla and in the posterior mandible, locations where the bone density often is low. A further aim was to evaluate the marginal bone level at oxidized implants and compare it with that of machined-surface implants used in a previous study. MATERIALS AND METHODS: Thirty-one patients were consecutively included in the study, and 37 edentulous areas in maxillas and posterior mandibles were treated. Bruxism and uncontrolled periodontal disease were exclusion criteria. Temporary prostheses were generally placed within 9 days but not after 16 days from implant placement. A previous study applying the same study design and clinical protocol but using machined-surface implants was used for comparisons. RESULTS: Of the 111 implants installed, 1 failed, giving an overall survival rate of 99.1% after 18 months. The prosthesis survival was 100%. The marginal bone resorption was 0.8 mm (standard deviation [SD], 1.0), as opposed to 1.6 mm (SD, 1.3) in the previous study with machined-surface implants, but was not statistically significantly different (p = .10). CONCLUSION: The present clinical protocol (aiming at high primary stability) and the use of oxidized titanium implants for early functional loading in the maxilla and the posterior mandible resulted in a high implant survival rate and a favorable marginal bone level during a follow-up of 18 months. The difference in marginal bone resorption between the oxidized implants in the present study and the machined implants from a previous investigation with the same study design was not statistically significant.

Adult↗