Treatment of atrophic mandibular fractures based on the degree of atrophy--experience with different plating systems: a retrospective study.

PURPOSE: The aim of this retrospective study was to evaluate the clinical outcome of fractures of the atrophic mandible based on the degree of atrophy and treatment by different plating systems. PATIENTS AND METHODS: Thirty patients with 40 fractures of atrophic mandibles were treated by open reduction and internal fixation at our department between 1994 and 2001. Twelve fractures occurred in Class I (between 15- and 20-mm bone height), 10 fractures in Class II (between 10 and 15 mm), and 18 fractures in Class III atrophy (<10 mm). The profile heights of plating systems used for stabilization varied from 0.5 to 2.2 mm and were applied with an intraoral (n = 37) and extraoral (n = 3) approach. RESULTS: In 36 fractures, bone healing was uneventful. Major complications (loose hardware or nonunion) occurred in 4 fractures: 2 in Class II and 2 in Class III atrophy. Major complications were observed with 1.4-mm (n = 3) and 2.2-mm (n = 1) plates. Minor complications (infections or dehiscence) were observed in 6 fractures: 3 in Class II and 3 in Class III atrophy. Hypesthesia of the inferior alveolar nerve was present 1 week and 1 year postoperatively in 39 and 16 fractures, respectively. CONCLUSIONS: Treatment of atrophic mandible fractures should be based on the degree of atrophy. More rigid fixation may be necessary in mandibles with less than 15 mm bone height.     

Reconstruction of an atrophied posterior mandible with the inlay technique and inorganic bovine bone block: a case report

A 53-year-old woman underwent bilateral reconstruction of her severely atrophic posterior mandible using inlay inorganic bovine bone block grafting. Four months later, a bone specimen was taken for histologic evaluation and eight dental implants were placed. These implants were loaded with a provisional prosthesis after another 4 months. When the definitive prosthesis was inserted 8 months postsurgery, all implants were osseointegrated. Histologic analysis showed that the grafted bone was lined with newly formed bone. The results indicate that inorganic bovine bone blocks might serve as an alternative to autogenous grafting for posterior mandibular augmentation using the inlay technique.     

Simultaneous sinus lifting and alveolar distraction of the atrophic maxillary alveolus for implant placement: a preliminary report

This article describes a procedure for performing simultaneous sinus lifting and alveolar distraction to augment an atrophic maxillary alveolus. This technique is a 1-stage operation that is indicated when the amount of native sinus floor bone is minimal (<5 mm). The technique is contraindicated when there is <2 mm of sinus floor,when a 2-stage operation is needed (sinus lifting, alveolar distraction osteogenesis). Postoperative complications are minimal.     

A precise radiographic method to determine the location of the inferior alveolar canal in the posterior edentulous mandible: implications for dental implants. Part 1: Technique

In severely atrophic or osteoporotic mandibles, the location of the inferior alveolar nerve may vary considerably, both superoinferiorly and mediolaterally. A clinician's ability to reliably locate this nerve within the mandible would permit the surgical planning of implant placement in the posterior edentulous mandible. Eight edentulous cadaver mandibles were studied. A technique that precisely locates the inferior alveolar nerve within the mandible is described. The technique will aid the surgeon in planning a surgical approach to the posterior mandible with reduced risk of injury to the inferior alveolar nerve.     

Sinus floor augmentation technique and simultaneous implant placement, part II: the 2-stage approach

The 1-stage osteotome sinus floor augmentation and simultaneous implant placement technique has been previously reported as a simple solution to heighten the maxillary posterior region to nearly 5- to 6-mm bone height. In this report, a patient with initial bone height of 2 to 3 mm in the extracted site of #3 was treated with the 2-stage osteotome technique. In the first stage, the sinus floor was grafted and augmented up to 5 to 6 mm. In the second stage, 9 months later, the same area was regrafted and the implant was placed. Eight months after the second stage, radiographs showed the entire 10-mm length of the implant was covered with new bone and the implant was solid and functional.     

Delayed immediate single-step maxillary sinus lift using autologous fibrin adhesive in less than 4-millimeter residual alveolar bone: a case report

This paper presents a combination of techniques to replace a missing first premolar in an atrophic posterior maxillary ridge with less than 4 mm of residual bone. Simultaneous sinus lift and implant placement were carried out as a delayed-immediate procedure 6 weeks following the extraction of the premolar. The osteotome technique was used to gain primary stability. Demineralized freeze-dried bone and deproteinized cancellous bovine bone (Bio-Oss) were used to create the bone volume. Autologous fibrin adhesive was subsequently used to stabilize the bone grafting materials both in the sinus and on the coronal part of the implant. This combined technique preserves the alveolar bone after extraction; simplifies the primary closure; avoids a second surgical site; and reduces the total operation time, cost, and inconvenience to the patient.     

Pedicled segmental rotation techniques for posterior mandible augmentation: a preliminary study

Rehabilitation of the atrophic posterior mandible is a challenge in dental practice. Conventional treatments include the segmental sandwich osteotomy or inlay bone grafting (IBG), onlay bone grafting (OBG), short implants, distraction osteogenesis, and inferior alveolar nerve transposition (IANT), each with its downsides. This case series is reported to introduce a modification of IBG – pedicled segmental rotation (PSR) for the reconstruction of co-existing vertical and horizontal defects in the posterior mandible. Ten healthy patients with vertical–horizontal defects (no vertical bone walls and basal bone width <5 mm) were included. Posterior mandibular defects were treated with PSR, PSR + IANT, or PSR + OBG. In PSR, a pedicle-preserved segment is up-fractured superiorly and then flipped 90° to a vertical position. The segment is then supported with inorganic bovine bone and autogenous bone particulates. Cone beam computed tomography was performed preoperatively and at the 4-month follow-up, in addition to clinical examinations. Soft tissue healing was uneventful. Radiomorphometric analysis showed a mean new bone volume of 647.79 ± 81.31 mm³ (ΔH = 7.13 mm), 836.99 ± 119.14 mm³ (ΔH = 7.8 mm), and 640.20 ± 50.13 mm³ (ΔH = 6.59) in the PSR, PSR + OBG, and PSR + IANT groups, respectively. The proposed PSR technique used in this case series showed promising results for vertical and horizontal augmentation of the atrophic posterior mandible before placement of dental implants.     

A prospective randomized study of 1- and 2-stage sinus inlay bone grafts: 1-year follow-up

The purpose of the present study was to compare the success of and surgical differences between 1- and 2-stage sinus inlay bone grafts and implants after 1 year in function. The individual risk for implant failure in grafted areas among 1-stage patients was about twice the risk in 2-stage patients (odds ratio 2.3, CI 0.6; 8.5). The risk for implant failure in non-grafted areas was significantly lower (P < .05) than in grafted areas, regardless of the technique used. Forty edentulous patients, selected according to strict inclusion criteria from consecutive referrals, were allocated to one or other of the 2 sinus-inlay procedures. Twenty patients received bone blocks fixed by implants to the residual alveolar crest in a 1-stage procedure (group 1). In another 20 patients, particulated bone was condensed against the antral floor and left to heal for 6 months before implants were placed (group 2). An almost equal number of implants was placed in the patients of each group, 76 in the 1-stage procedure and 74 in the 2-stage procedure. Additionally, 72 and 66 implants were placed in the anterior non-grafted regions of group 1 and group 2 patients, respectively. After 1 year in function, a total of 20 implants failed in 1-stage patients, versus 11 in 2-stage patients. Sixteen and 8 implants, respectively, of these were placed in grafted bone. All but one 1-stage patient received the planned fixed prosthetic restorations, but 1 restoration was redesigned after the first year in function because of a functionally unacceptable prosthetic design. At the 1-year follow-up, one 2-stage patient lost her prosthesis as the result of multiple implant failures. Bruxism and postoperative infections were the only parameters that could be related to implant failure, however, depending on the statistical method used.     

Avoiding injury to the inferior alveolar nerve by routine use of intraoperative radiographs during implant placement

Injury to the inferior alveolar nerve during implant placement in the posterior atrophic mandible is a rare but serious complication. Although a preoperative computerized tomography scan can help determine the distance from the alveolar ridge to the nerve canal, variables such as magnification errors, ridge anatomy, and operator technique can increase the chance for complications. The routine use of intraoperative periapical radiographs during the drilling sequence is an inexpensive and reliable tool, allowing the operator to confidently adjust the direction and depth of the implant during placement. Most important, it helps avoid the risk of injury to the inferior alveolar nerve in cases in which there is limited vertical alveolar bone. Using this technique for 21 implants placed in the posterior atrophic mandible, with less than 10 mm of vertical bone to the inferior alveolar nerve canal, the authors observed no incidents of postoperative paresthesia.     

Inlay versus Onlay Iliac Bone Grafting in Atrophic Posterior Mandible: A Prospective Controlled Clinical Trial for the Comparison of Two Techniques

Purpose: To compare the efficacy of inlay and onlay bone grafting techniques in terms of vertical bone formation and implant outcomes for correcting atrophic posterior mandibles.
Materials and Methods: Twenty surgical sites were assigned to two treatment groups, inlay and onlay, with iliac crest as donor site. After 3 to 4 months, 43 implants were placed and loaded 4 months later. The median follow up after loading was 18 months.
Results: For the inlay versus onlay group, median bone gain was 4.9 versus 6.5 mm ( p  = .019), median bone resorption was 0.5 versus 2.75 mm ( p  < .001), and median final vertical augmentation was 4.1 versus 4 mm ( p  = .190). The implant survival rate was 100% in both groups, while the implant success rate was 90% versus 86.9% ( p  = .190, not significant). A minor and major complication rate of 20% and 10%, respectively, for both groups was encountered.
Conclusions: Inlay results in less bone resorption and more predictable outcomes, but requires an experienced surgeon. In contrast, onlay results in greater bone resorption and requires a bone block graft oversized in height, but involves a shorter learning curve. Once implant placement has been carried out, the outcomes are similar for both procedures.     

Treatment of patient with Papillon-Lefevre syndrome with short dental implants: a case report

Papillon-Lefevre syndrome (PLS) is an autosomal recessive disorder. Main features of PLS are hyperkeratosis of palms and soles concomitant with premature loss of primary and permanent dentition due to progressive periodontitis. Dental management of patients with PLS is usually challenging because of early excessive loss of alveolar bone support. We describe dental rehabilitation of a 34-year-old patient with PLS with severely atrophic mandible by means of 2 short (6 mm) dental implants between 2 mental foramina supporting an implant retained complete denture. After 1 year of follow-up period, the patient was doing well and there was no sign of bone resorption. In patients with PLS, dental osseointegrated implants (even with shorter lengths) can be safely used for atrophic mandibles instead of invasive preprosthetic applications such as bone augmentation, nerve lateralization, or alveolar distraction to avoid possible complications.     

A 5-year prospective multicenter study on 1-stage smooth-surface Brånemark System implants with early loading in edentulous mandibles

PURPOSE: The purpose of the current prospective multicenter study was to evaluate the 5-year implant success and peri-implant conditions of smooth-surface Br?nemark System implants when using a novel technique including a 1-stage surgical procedure with early loading in edentulous mandibles. MATERIALS AND METHODS: The study protocol included 1-stage surgery as well as placement of the definitive prosthesis within 6 weeks after implant insertion (ie, early loading). Clinical evaluation, as well as evaluation of function and esthetics, was performed at each follow-up visit. Radiographs were obtained at connection of the prostheses and at the 1, 3-, and 5-year check-ups. RESULTS: A total of 40 patients with a mean age of 56 years (range, 30 to 70) were included in the study. In all, 170 implants were placed in between the mental foramina, of which 120 implants in 30 patients were associated with overdenture treatment and 50 implants in 10 patients with fixed complete dentures. Twelve implants failed in 6 patients. The cumulative implant survival rate was 92.9% after both 1 and 5 years of follow-up. Another 3 implants were recorded as mobile but still in function when individually checked at the 5-year visit, which resulted in a cumulative success rate of 91.0%. Mean bone remodeling over the study period was less than 0.1 mm/y after the first year of loading, resulting in a mean marginal bone level of 0.66 mm (SD 0.73, n = 138) apical to the implant collar reference point after 5 years. CONCLUSIONS: One-stage, early loaded smooth-surface Br?nemark System implants functioned well for the majority of patients with edentulous mandibles. Stable peri-implant conditions were observed. Bone remodeling resulted in a mean bone level above the first implant thread after 5 years. The somewhat lower success rate of 91.0% compared to a 2-stage procedure may be related to generous inclusion criteria and to a learning curve involving a novel treatment procedure.     

Analysis of short implants and lateralization of the inferior alveolar nerve with 2-stage dental implants by finite element method

There are difficulties for dental implant use in posterior mandible when there is little bone height for implant placement. Among the treatment alternatives available, there is no direct comparison between short implants and conventional implants placed with lateralization of the inferior alveolar nerve. The present study aimed to comparatively evaluate the risk of peri-implant bone loss of the above treatments. With this aim, computed tomography scans of mandibles were processed, and implants and prosthetic components were reverse engineered for reconstruction of three-dimensional models to simulate the biomechanical behavior of 3-element fixed partial dentures supported by 2 osseointegrated implants, using simulations with the finite element method. The models of implants were based on MK III implants (Nobel Biocare) of 5- and 4-mm diameter by 7-mm length, representing short implants, and 4- and 3.75-mm diameter by 15-mm length, representing implants used in lateralization of the inferior alveolar nerve. All models were simulated with prestress concerning the stresses generated by the torque of the screw. Axial and oblique occlusal loads at 45% were simulated, resulting in 8 different simulations. The results showed that the risk for bone loss in osseointegrated implants is greater for treatments with short implants.     

Aumento verticale nelle atrofie mandibolari: evidenze scientifiche

Objectives

The aim of this article is to evaluate the most effective reconstructive-regenerative and/or implant techniques available for increasing the vertical bone height of atrophic mandibles, according to the biological material used.

Materials and methods

We analyzed data from 14 randomized clinical trials that met the criteria for inclusion in Cochrane reviews.

Results and conclusions

Vertical bone regeneration can be achieved in the atrophic posterior mandible, but complications are frequent. Furthermore, it is not clear which technique is the best. When the atrophic mandible is totally edentulous, the best approach seems to be intraforaminal placement of short implants (8-11 mm). It is a relatively easy procedure that can be done on an outpatient basis and is associated with lower morbidity.     

Staged reconstruction of the severely atrophic mandible with autogenous bone graft and endosteal implants.

PURPOSE: Vastly different surgical techniques have been advocated for osseous reconstruction of the severely atrophic mandible. Endosseous implants placed in autologous bone grafts have been proposed to minimize graft resorption and restore function; however, sufficient bone must exist to support the implants and prevent pathologic fracture. The purpose of this retrospective analysis was to assess the efficacy of autologous bone grafting and the subsequent placement of endosteal implants as a staged procedure in patients with severely atrophic mandibles. MATERIALS AND METHODS: The records of all patients presenting to The University of North Carolina for treatment from 1997 to 1999 with atrophic mandibles (vertical mandibular height <7 mm as measured on panoramic radiographs in at least 1 site at the mandibular midline and at the thinnest portion of the mandibular body) were reviewed. Bone height was assessed preoperatively, immediately postoperatively, at the time of implant placement (4 to 6 months), and again at 12 and 24 months after bone grafting from posterior iliac crest to the mandible via an extraoral approach. Five endosteal implants were subsequently placed in each patient as a delayed procedure 4 to 6 months after bone grafting, and prosthetic rehabilitation was completed with implant supported prostheses. RESULTS: Fourteen consecutive patients were identified with a median preoperative bone height of 9 mm (interquartile range, 25th to 75th percentile [IQ], 7 to 10 mm) in the mandibular midline and 5 mm (IQ, 2 to 5 mm) in the body region. There were no perioperative complications. Median estimated blood loss during the bone graft procedure, as estimated by the surgeon and the anesthesiologist, was 300 mL (IQ, 150 to 1,100 mL), and 1 patient required blood transfusion secondary to symptomatic anemia. The mean loss of vertical bone height after grafting and during the 4 to 6 months before implant placement was 33%. After implant placement and at 12 months, the vertical bone loss was negligible in the implant-supported region and less than 11% in the body region. CONCLUSION: Reconstruction of the severely atrophic mandible using autogenous corticocancellous bone grafts followed by placement of osseointegrated implants in 4 to 6 months can restore and maintain mandibular bone sufficient to support implants and facilitate successful restoration of occlusion. A prospective study is planned to identify predictors of successful outcomes compared with other surgical/prosthetic treatment.     

Lateralization of the inferior alveolar nerve with simultaneous implant placement: a modified technique

PURPOSE: Several nerve repositioning techniques have ben presented in the literature, each with limitations. This article presents a new technique involving the use of 2 osteotomies, with minimizes particularly the potential duration of sensory disruption and the risk of nerve paresthesia and inadvertent nerve transection or compression. MATERIALS AND METHODS: Ten patients ranging in age from 47 to 67 years were selected for nerve lateralization utilizing the modified technique. A total of 23 cylindrical implants were placed. An average follow-up period was 29.8 months. RESULTS: Of the 10 patients, 4 experienced total return of sensation within 3 to 4 weeks. One patient experienced complete recovery at 6 weeks. DISCUSSION: Creating 2 osteotomies as described minimizes the chances for postoperative neuropraxia and nerve paresthesia or anesthesia. CONCLUSION: When there is moderate-to-severe bone resorption of the mandible posterior to the mental foramen, repositioning the inferior alveolar nerve using both an anterior and posterior osteotomy allows for more bone to accommodate ideal placement and greater length of implant.     

A new design for all-ceramic inlay-retained fixed partial dentures: a report of 2 cases.

In a previous clinical study, all-ceramic resin-bonded 3-unit inlay-retained fixed partial dentures (IRFPDs) had a significantly worse outcome in the posterior region than did crown-retained 3-unit FPDs made from the same material. Debonding or fractures were causes of failure. To improve the clinical outcome of IRFPDs, a new framework design was developed: (1) The inlay retainers were made out of CAD/CAM-manufactured zirconia ceramic to improve fracture resistance, and additional veneering of the inlays was omitted. (2) The inlay retainers were completed with a shallow occlusal inlay (1-mm minimum thickness) and an oral retainer wing (0.6-mm minimum thickness). The wings were designed to reduce stress on the inlay retainer caused by torsion forces when the FPD is loaded nonaxially and to increase the enamel adhesive surface area. The pontic was circumferentially veneered with feldspathic porcelain. The clinical and laboratory procedures of this new treatment modality are described, and 2 exemplary clinical cases are presented. This new preparation and framework design might improve the clinical outcome of all-ceramic resin-bonded IRFPDs. However, adequate evidence of long-term safety and efficacy is required before this new design can be recommended for general clinical practice.     

Biologic mechanical advantages of 3 different cranial bone grafting techniques for implant reconstruction of the atrophic maxilla.

PURPOSE: The purpose of this study was to test the mechanical capacities of 3 different bone grafting techniques in the atrophic maxilla when co-stabilized with dental implants. Reconstruction of the atrophic maxilla is a difficult clinical challenge and implants cannot be placed without adequate bone. METHODS: The biomechanical performance of 3 different grafting techniques was evaluated in vitro using a maxillary model, cadaveric cranial bone blocks, and dental implants. A maxillary model fabricated from polyurethane (sawbone) was selected as a substrate for this study because of consistency in shape, size, and mechanical properties. This anatomic model was more consistent than different cadaveric maxilla, where significant variation was found to exist among atrophic specimens. Cadaveric cranial bone graft blocks were secured to the model maxilla (sandwich, ridge only, and sinus inlay) with a dental implant. The strength of the implant/bone graft complex was tested to failure in an Instron machine (Instron Inc, Canton, MA). RESULTS: The 3 bone grafting methods showed significantly different deformation and strength characteristics. The sandwich technique enhanced resistance to deformation under higher imposed loads. The location of the graft influenced the overall mechanical performance (eg, the ridge onlay) and showed a significantly higher resistance to compressive loads applied toward the alveolar ridge (mastication force). CONCLUSION: The ridge onlay grafting procedures created a higher biomechanical tolerance to imposed load than the sinus grafting (sinus inlay). Sinus grafting, although successful, was not the most ideal location for immediate mechanical loading resistance when compared with ridge augmentation in this in vitro model.     

Vertical ridge augmentation of atrophic posterior mandible using an inlay technique with a xenograft without miniscrews and miniplates: case series

Background: Rehabilitation of partially or totally edentulous posterior mandible with implant‐supported prosthesis has become a common practice in the last few decades, with reliable long‐term results. The use of miniscrews and miniplates have been reported to increase the risk of fracture of the osteotomy segments. The purpose of this case series was to use an inlay technique, without the use of miniscrews and miniplates for stabilization of the transported bone fragments. Materials and methods: Nine consecutive patients (six men and three women) aged between 26 and 51 years (mean 44 years) were enrolled in this study. A horizontal osteotomy was performed 2–3 mm above the mandibular canal, and two oblique cuts were made using a piezosurgery device. The final phase of the osteotomy was performed with chisels. The osteotomized segment was then raised in the coronal direction, sparing the lingual periosteum. Two miniblocks of xenograft without miniscrews and miniplates were inserted mesially and distally between the cranial osteotomized segment and the mandibular basal bone. The residual space was filled with particles of cortico‐cancellous porcine bone. Four months after surgery, a panoramic X‐ray was taken before implant insertion. A bone trephine with an internal diameter of 2 mm was used as the second dental drill to take a bone core biopsy during preparation of the #35 and #37 or #45 and #47 implant sites. Results: The postoperative course was uneventful in seven of the nine patients. No dehiscence of the mucosa was observed at the marginal ridge of the mobilized fragment. Newly formed bone was present near the osteotomized segments, and was observed in the bottom half of the specimens and was identified by its higher affinity toward the staining. Newly formed bone was observed to be in close contact with the particles of biomaterials. No gaps or connective tissue were present at the bone–biomaterial interface. Histomorphometry demonstrated that 44±2.1% of the specimens was composed by newly formed bone, 18±0.8% by marrow spaces, and 33±2.4% by the residual grafted biomaterial. Conclusion: The rigidity of the equine collagenated block allowed to eliminate the use of miniscrews and miniplates and simplified the technique. Moreover, the rigidity of the block allowed maintenance of the space. To cite this article:
Scarano A, Carinci F, Assenza B, Piattelli M, Murmura G, Piattelli A. Vertical ridge augmentation of atrophic posterior mandible using an inlay technique with a xenograft without miniscrews and miniplates: case series.
Clin. Oral Impl. Res. 22 , 2011; 1125–1130
doi: 10.1111/j.1600‐0501.2010.02083.x     

Endosseous implants and bone augmentation in the partially dentate maxilla: an analysis of 17 patients with a follow-up of 29 to 101 months

PURPOSE: The aim of this study was to analyze the survival rate of endosseous implants placed in the partially dentate maxilla treated with sinus inlay block bone grafts. MATERIALS AND METHODS: Seventeen patients were subjected to bone augmentation procedures prior to or in conjunction with implant placement. Bone volumes were regarded as insufficient for implant treatment unless a bone grafting procedure was performed. The patients were treated with sinus inlay block bone grafts and endosseous implants in a 1- or 2-stage procedure. A total of 69 implants were placed in the patients who were followed for 29 to 101 months (mean, 53.1 months). The retrospective patient group was also prospectively followed using a standardized clinical and radiographic study design. RESULTS: The implant survival rate was 91.3% (63/69). All implants were lost during the period from abutment connection to connection of the definitive prosthesis. All bone grafts were stable. Bone grafts supported 48 implants, of which 5 failed (10.4%). In the residual bone, 21 implants were placed, of which 1 failed (4.8%). All patients received a fixed partial prosthesis, which was stable during the follow-up period. CONCLUSION: The results of this investigation revealed a satisfactory clinical outcome of implant placement in grafted partially dentate maxillae after a mean follow-up of 53.1 months.