Reduced Arch Length as a Factor for 4-Implant Immediate Function in the Maxilla: A Technical Note and Report of 39 Patients Followed for 5 Years.

PURPOSE: To determine whether maxillary arch length deficiency treated with a V-4 implant placement method is adequate for immediate functional loading during a 5-year follow-up. MATERIALS AND METHODS: Thirty-nine patients were treated with maxillary immediate function from January 3, 2011 to February 28, 2011 and followed for a period of 5 years. Arch length after implant placement was measured retrospectively around the arch from the anterior sinus wall to the contralateral anterior sinus wall in a mid-alveolar arc on the occlusal view of the preoperative computed tomogram. Eight patients with an osseous arch length shorter than 45 mm were treated with a V-4 pattern. Thirty-one patients with an arch length longer than 45 mm were treated with an M-4 placement pattern. The aim was to determine whether immediate function with a shorter arch length could be obtained on the day of surgery using a V-4 placement and whether implant stability would persist during the 5-year follow-up. Any surgical events, including lost implants, were recorded in the charts. Late follow-up was performed by panoramic films. RESULTS: During the 2-month treatment period, 39 patients (8 with V-4 placement and and 31 with M-4 placement) received maxillary treatment. The 8 patients in the V-4 group had an arch length average of 36.0 mm available for osseointegration. The 31 patients in the M-4 group had an arch length average of 56.6 mm. There were 7 implant losses (and replacements) during the 5-year follow-up, 1 in the V-4 group and 6 in the M-4 group. CONCLUSION: When the arch length bone available for osseointegration is shorter than 45 mm, a V-4 placement strategy might enable successful 4-implant fixed denture support for immediate function.

Imperforate titanium shell enclosing recombinant human bone morphogenetic protein-2-induced bone formation for high-profile dental implants in rabbit tibia.

PURPOSE: To evaluate the use of a nonperforated titanium occlusive device over high-profile dental implants in rabbit tibia using recombinant human bone morphogenetic protein-2 (rhBMP-2) in an absorbable collagen sponge (ACS) for augmentation grafting. MATERIALS AND METHODS: Eight New Zealand white rabbits were used for the experiment. All rabbits underwent computed tomography of the right tibia. A custom titanium shell was manufactured for each rabbit using a computer-assisted design to confine the graft. Three high-profile implants were placed in the right tibia of each rabbit; the middle implant was placed 8 mm in supracrestal fashion and the adjacent implants were placed 5 mm in supracrestal fashion. There were 4 groups (n = 2 per group): non-shell control, titanium shell only, titanium shell over buffered collagen, and titanium shell over the ACS enriched with rhBMP-2. The animals were sacrificed after 6 or 12 weeks. Histologic preparation was carried out to evaluate bone formation. RESULTS: After 6 weeks, negligible bone growth was found around the implants. After 12 weeks, there was minimal bone formation around the implants in the control group, whereas in the group treated with ACS enriched with rhBMP-2, the titanium shell was filled with mature bone, which was expressed at the implant surface, the shell's interior, and the exterior surfaces. CONCLUSION: The placement of ACS enriched with rhBMP-2 beneath an occlusive nonperforated titanium shell confining high-profile dental implants resulted in visibly more formation of mature bone.

Maxillary V-4: Four implant treatment for maxillary atrophy with dental implants fixed apically at the vomer-nasal crest, lateral pyriform rim, and zygoma for immediate function. Report on 44 patients followed from 1 to 3 years.

STATEMENT OF PROBLEM: The V-4 implant placement technique is important for restoring patients with maxillary atrophy, but little has been documented on the outcomes of these treatments. PURPOSE: The purpose of this study was to evaluate the outcome of immediate function after 1 year when implants were placed without vertical bone augmentation in Cawood-Howell Classes IV-VI maxillary atrophy (Class C-D by the "all-on-four" site classification) with the nasal crest, lateral pyriform rim, and sometimes the zygoma for apical implant fixation. MATERIAL AND METHODS: Function of implants that had been immediately loaded were studied retrospectively after 1 year in 44 patients from 2 different clinics. For each patient studied, 2 angled implants were placed in the midline in the nasal crest/vomer area, and typically, 2 implants were engaged apically in the lateral pyriform rim bilaterally. All 4 of the implants used were angled toward the midline in a V formation, termed "V-4" implant placement. Insertion torque, anterior-posterior spread, implant diameter, implant length, and posterior cantilever were recorded. Implant survival and bone stability were assessed after 1 year. When the lateral pyriform was highly deficient (Class D), zygomatic implants were used posteriorly. RESULTS: A total of 179 implants were placed in 44 patients followed for 1 to 3 years. Six implants were lost, all in 1 patient. Anterior-posterior spread averaged 16 mm, with an average cantilever of 7.5 mm. Except for the lost implant sites, bone levels were stable throughout treatment for all patients. CONCLUSIONS: The use of 4 implants angled toward the midline, including 2 implants placed into a V-shaped point at the nasal crest and 2 implants placed into an M-shaped point at the pyriform rim bilaterally, showed good stability after 1 year despite gross absence of bone mass as a result of severe maxillary atrophy. The V-4 placement pattern is important for patients with deficient bone mass between the sinus and nasal cavities. In Class D situations where lateral nasal rim bone mass is nearly absent, zygomatic implants can be used.

Anterior sinus grafts for angled implant placement for severe maxillary atrophy as an alternative to zygomatic implants for full arch fixed restoration: technique and report of 5 cases.

We report on 5 cases, 4 to demonstrate the anterior sinus graft technique for angled implant placement and 1 comparison zygomatic case, all for immediate function implant restoration despite severe maxillary atrophy. The sinus graft was low volume, with less than 5 mL of bone morphogenetic protein-2/absorbable collagen sponge allograft in a 50% mixture placed against the lateral nasal wall, often in conjunction with implant placement. The importance of the technique is to simplify treatment of severe maxillary atrophy for immediate function to avoid the need for zygomatic implant placement in the vast majority of severely atrophic maxillas.

Alveolar sandwich osteotomy in resorbed alveolar ridge for dental implants: a 4-year prospective study.

PURPOSE: To answer whether severe vertical alveolar defects can be resolved using the sandwich osteotomy technique with xenograft material as filler and to evaluate the predictability of this procedure. MATERIALS AND METHODS: Ten graft sites (5 mandibular and 5 maxillary) in 9 patients treated at the Department of Oral and Maxillofacial Surgery, Hadassah Medical Center, were included in the present study. The patients underwent vertical bone augmentation using the sandwich osteotomy technique filled with xenograft material. The degree of bone augmentation was analyzed clinically at surgery and 4 to 6 months later from the computed tomography images taken just before the sites had been rehabilitated using dental implant insertion. A trephine histologic analysis was performed during implantation at 1 maxillary site. RESULTS: The mean vertical bone gain in the interval between the sandwich osteotomy and implementation was 6 mm (range 4 to 10), and it remained stable after 4 to 6 months. In 2 cases, additional horizontal bone augmentation was needed. All graft sites were rehabilitated using dental implants with satisfactory results. In 3 cases, gingival porcelain was required for the final prosthesis. Histologic examination revealed vital segmentized bone and remodeling of the filled gap. CONCLUSIONS: The interpositional alveolar bone graft using xenograft filler appears to be a viable and predictable alternative to block grafting or guided bone regeneration, resulting in good final results, with substantial vertical bone gain, even for challenging cases.

Complete arch site classification for all-on-4 immediate function.

Complete arch immediate function of dental implants requires a treatment protocol that takes advantage of residual areas of cortical bone for the apical fixation of implants. A site and jaw bone classification is proposed that has been in use since 2006 for all stages of atrophy for both jaws. The use of the classification is strictly for immediate function based on specific cortical bone sites in the facial skeleton to assist practitioners in diagnosis, treatment planning, and interdisciplinary communication, as well as to reduce human error in patient management. A recent series of 100 consecutive arches that were treated according to this classification is presented.

The mechanism of bone metabolism in a Sprague Dawley rat model of mandibular osteoradionecrosis.

Background: Osteoradionecrosis (ORN) is a serious complication of radiotherapy for head and neck cancer. There is currently a lack of data on the dynamic expression of genes related to bone remodeling during the development of mandibular ORN. This study aimed to establish an animal model of ORN in Sprague Dawley (SD) rats, detect the expression of genes related to bone metabolism, observe morphological changes, and clarify the mechanism of ORN. Methods: A total of 24 male SD rats in group 1 were randomly divided into four groups (n=6/group): group a, normal control; group b, simple tooth extraction; group c, simple radiation; and group d, radiation extraction group. The right mandible of rats in groups c and d was irradiated with a single dose of 35 Gy. The right mandibles were taken from each group for morphological observation 90 days after irradiation. SD rats in group 2 (n=144) were randomly divided into four groups (in similar fashion to group 1 but with groups a', b', c', and d'). Samples were collected at six time points after irradiation. Histopathological changes were observed, and Western blotting (WB) was used to analyze protein expression. Results: The formation of dead bone and pathological fracture was visible under micro-computed tomography (micro-CT), and tissue biopsy showed late fibrosis repair. In group d', osteogenesis and osteoclasis coexisted in the early irradiation stage. Vascular endothelial growth factor (VEGF) receptor expression was lower in groups c' and d' than in group a'. On day 45, runt-related transcription factor 2 (RUNX2) expression in group d' was lower than that in the other groups. The ratio of receptor activator of nuclear factor-κß ligand to osteoprotegerin (RANKL:OPG) differed significantly among groups b', c', and d' on the 45th day (d' > c' > b'). Conclusions: Radiation and vascular function damage resulted in the lower expression of VEGF. The first 15 days after radiation was mainly characterized by new bone formation. After 15 days, bone resorption increased. Tooth extraction trauma can aggravate the bone metabolism imbalance and promote ORN occurrence. These findings shed light on the mechanism of ORN.

Indications for implant-supported rehabilitation of the posterior atrophic maxilla: A multidisciplinary consensus among experts in the field utilising the modified Delphi method.

PURPOSE: To establish consensus-driven guidelines that could support the clinical decision-making process for implant-supported rehabilitation of the posterior atrophic maxilla and ultimately improve long-term treatment outcomes and patient satisfaction. MATERIALS AND METHODS: A total of 33 participants were enrolled (18 active members of the Italian Academy of Osseointegration and 15 international experts). Based on the available evidence, the development group discussed and proposed an initial list of 20 statements, which were later evalu-ated by all participants. After the forms were completed, the responses were sent for blinded ana-lysis. In most cases, when a consensus was not reached, the statements were rephrased and sent to the participants for another round of evaluation. Three rounds were planned. RESULTS: After the first round of voting, participants came close to reaching a consensus on six statements, but no consensus was achieved for the other fourteen. Following this, nineteen statements were rephrased and sent to participants again for the second round of voting, after which a consensus was reached for six statements and almost reached for three statements, but no consensus was achieved for the other ten. All 13 statements upon which no consensus was reached were rephrased and included in the third round. After this round, a consensus was achieved for an additional nine statements and almost achieved for three statements, but no consensus was reached for the remaining statement. CONCLUSION: This Delphi consensus highlights the importance of accurate preoperative planning, taking into consideration the maxillomandibular relationship to meet the functional and aesthetic requirements of the final restoration. Emphasis is placed on the role played by the sinus bony walls and floor in providing essential elements for bone formation, and on evaluation of bucco-palatal sinus width for choosing between lateral and transcrestal sinus floor elevation. Tilted and trans-sinus implants are considered viable options, whereas caution is advised when placing pterygoid implants. Zygomatic implants are seen as a potential option in specific cases, such as for completely edentulous elderly or oncological patients, for whom conventional alternatives are unsuitable.

Segmental alveolar split combined with dental extractions and osteotome sinus floor intrusion in posterior maxilla using BMP-2/ACS allograft for alveolar reconstruction: technical note and report of three cases.

The present report is of 3 patients who underwent a new technique for the posterior maxilla. After multiple dental extractions, the segment's alveolar was split to widen it, and the sinus floor was intruded using an osteotome to lengthen the alveolar height and then grafted with a bone morphogenetic protein-2/absorbable allograft without primary wound closure. Implant placement occurred 4 months later, followed by prosthetic restoration.

Trans-sinus dental implants, bone morphogenetic protein 2, and immediate function for all-on-4 treatment of severe maxillary atrophy.

PURPOSE: The aim of this study was to evaluate the clinical outcomes of trans-sinus dental implant placement by use of bone morphogenetic protein 2 (BMP-2) grafting and immediate functional loading by the all-on-4 scheme. PATIENTS AND METHODS: After bone reduction to create the all-on-4 shelf or because of severe maxillary atrophy and prominent sinus anatomy, 10 patients were selected to undergo trans-sinus implant placement and simultaneous BMP-2 sinus floor grafting for immediate provisional loading. Insertion torque was measured upon implant placement. Patients were followed up for at least 1 year after final restoration when either a computed tomography scan or panoramic radiograph was obtained and analyzed for the presence of trans-sinus peri-implant bone. Hounsfield units were recorded mid sinus graft. RESULTS: Of 19 trans-sinus implants, 18 remained integrated at the 1-year follow-up, for a 5.2% failure rate. All sinus grafts formed bone, with a mean of 460 Hounsfield units. Final fixed prostheses were completed for all 10 patients. CONCLUSION: Trans-sinus dental implant placement with BMP-2 grafting to gain anterior-posterior spread for immediate function by use of all-on-4 treatment appears to be a viable alternative to the use of zygomatic implants in the presence of severe maxillary atrophy.

Radiographic protrusion of dental implants in the maxillary sinus and nasal fossae: A multidisciplinary consensus utilising the modified Delphi method.

The aim of the present study was to generate an international and multidisciplinary consensus on the clinical management of implant protrusion into the maxillary sinuses and nasal fossae. A total of 31 experts participated, 23 of whom were experts in implantology (periodontologists, maxillofacial surgeons and implantologists), 6 were otolaryngologists and 2 were radiologists. All the participants were informed of the current scientific knowledge on the topic based on a systematic search of the literature. A list of statements was created and divided into three surveys: one for all participants, one for implant providers and radiologists and one for otolaryngologists and radiologists. A consensus was reached on 15 out of 17 statements. According to the participants, osseointegrated implants protruding radiographically into the maxillary sinus or nasal fossae require as much monitoring and maintenance as implants fully covered by bone. In the event of symptoms of sinusitis, collaboration between implant providers and otolaryngologists is required. Implant removal should be considered only after pharmacological and surgical management of sinusitis have failed.

Island osteoperiosteal flaps with interpositional bone grafting in rabbit tibia: preliminary study for development of new bone augmentation technique.

PURPOSE: Loss of alveolar vertical height is one of the most challenging conditions in the field of implantology. A few augmentation techniques have been proposed to address this challenge, including guided bone regeneration, alveolar distraction osteogenesis, sandwich osteotomies and autogenous block grafting. This is a pre-clinical study of lengthening the alveolar bone height using a thin osteoperiosteal bone flap, the "island bone flap" or i-flap, to establish vitality, stability and incorporation of the augmentation material after healing. MATERIALS AND METHODS: A rabbit tibia model was designed for this study and included 8 rabbits. An osteoperiosteal osteotomy was performed through the periosteum cutting 1 mm of the outer cortex of the bone in order to elevate a bone flap. The bone flap was detached, and remained attached to the periosteum as a free floating osteoperiosteal flap, and the resultant defect was filled with xenograft. RESULTS: The histological analysis demonstrates formation of maturing trabeculae in the site of the i-flap. In cases of trauma to the bone marrow during the surgical procedure, a centripetal gradient of bone remodeling from the surgical site toward the periphery was evident, while the bony component of the i-flap maintained vital. CONCLUSIONS: Creating a free floating osteoperiosteal flap, used here with interpositional grafting in a rabbit tibia, appears to heal by both appositional modeling and creeping substitution remodeling. Volumetric augmentation persisted despite exuberant bone turnover in this animal model. This technique holds promise as a possible augmentation bone grafting approach for use in alveolar reconstruction.

Minimum criteria for immediate provisionalization of single-tooth dental implants in extraction sites: a 1-year retrospective study of 100 consecutive cases.

PURPOSE: Minimum criteria were used in the placement of 100 consecutive provisional restorations on single-tooth dental implants placed into extraction sites within 3 days of surgery. MATERIALS AND METHODS: Provisional restorations were placed on 4.1- and 4.8-mm diameter standard ITI (Straumann, Waltham, MA) implants in the anterior mandible and maxilla in 100 treatment sites over a 3-year period. Provisionals were placed despite low insertion torque values of 15 N-cm or 50 implant stability quotient using radiofrequency analysis. Implants had final impressions for definitive restorations done 8 to 12 weeks after implant placement. All patients were recalled 1 year after restoration and evaluated according to parameters suggested by Albrektsson et al (Int J Oral Maxillofac Implants 1:11, 1986). RESULTS: One implant was not osseointegrated. The remaining implants were judged successful at the 1-year recall appointment. CONCLUSION: Immediate provisionalization of implants placed into fresh extraction sites can be effective even when minimal provisionalization criteria are met.

The all on 4 shelf: mandible.

The use of full arch alveolar reduction as an aide to doing All on 4 implant restoration in the mandible is presented. The osteoplasty is described as a flat "shelf" on which to place the restoration. The shelf approach is used to establish optimal implant position and angulation as well as to define anatomy to maximize implant fixation for immediate load prosthetics.

Island osteoperiosteal flap for alveolar bone reconstruction.

The island osteoperiosteal flap (I-flap) is introduced as a modified alveolar split bone grafting technique used to gain width and modify the facial or buccal bone plate position. Three case examples are shown as well as animal histology indicating the possible development of this new surgical procedure as an adjunct for alveolar augmentation and implant therapy.

The All-on-4 shelf: maxilla.

All-on-4 treatment is facilitated by bone reduction to create prosthetic restorative space, establish maximum anterior posterior spread of implants, and to avoid pneumatized sites. Unlike a reduction alveloplasty for denture placement, the All-on-4 shelf enables optimal surgical prosthetic management of implant placement for the fixed hybrid prosthesis.

All-on-4 treatment of highly atrophic mandible with mandibular V-4: report of 2 cases.

This report contains a technical note and 2 case reports of the "all-on-4" treatment of the highly resorbed mandible. The use of 4 angled implants directed toward the midline of the mandible at 30 degrees angles provides the advantage of increased implant length and adequate insertion torque for immediate temporization. The technique engages or perforates the inferior border with implants placed in a spaced distribution to avoid fracture of the mandible. The technique is proposed as an alternative to bone graft reconstruction.

The maxillary M-4: a technical and biomechanical note for all-on-4 management of severe maxillary atrophy--report of 3 cases.

We present a technical note and 3 case reports of all-on-4 treatment of highly resorbed maxillas. The use of 4 angled implants, placed at as much as 30 degrees off axis, that engage the lateral nasal wall bone provide high torque fixation for immediate temporization. The technique is proposed as an alternative to sinus grafting and for use with multiple implants or zygomatic implants.

Marginal bone stability using 3 different flap approaches for alveolar split expansion for dental implants: a 1-year clinical study.

PURPOSE: Width augmentation for the alveolar process using alveolar split procedures has not been studied in a comparative study with regard to marginal bone stability. Most research in this regard has used implant osseointegration as an endpoint for the success of the bone grafting procedure. The purpose of the present clinical trial was to retrospectively evaluate the stability of the buccal crestal bone around dental implants placed into alveolar split graft sites using 3 different approaches: a minimal flap, a partial-thickness flap, and a full mucoperiosteal flap. Implants were placed simultaneously or delayed to alveolar split grafting. The aim of the present study was to do a comparative analysis of these 3 techniques by clinical detection for the presence or absence of marginal bone using a periodontal probe 1 year after implant restoration. The working hypothesis was that detachment or disturbance of the blood supply of the buccal plate would be influenced by the flap procedure used and would therefore affect the late marginal bone stability around the implants. MATERIALS AND METHODS: A total of 40 consecutive patients were treated in 2 different practice locations (20 at each office) with alveolar split procedures and simultaneous implant placement, using 3 different flap approaches and were seen again after 1 year at the 2 private office locations. The patients were in general good health, without active periodontal disease. All patients were nonsmokers. Patients with diabetes mellitus were excluded from the study. The aim of the present study was to establish the stability of the mobilized buccal bone plate, which could only be observed indirectly. The method used to detect the presence or absence of buccal marginal bone was a blunt periodontal probe used in the sulcus on the facial surface of the restored implant or a sharp explorer used transgingivally to detect marginal bone presence. However, the bone thickness could not be established using either of these methods. This was done in both practice locations by the surgeon who had performed the procedure (in a few cases, open flap procedures were done up to 1 year after grafting, which permitted direct observation of the original treatment site). The 3 different flap approaches studied were full-thickness flap reflection, partial-thickness flap reflection, and minimal flap reflection of the osteoperiosteal flap approach to crestally split and then widen the alveolus. RESULTS: A total of 40 consecutive patients treated with 65 alveolar split expansion procedures done in 2 practice locations during a 2-year period were statistically analyzed retrospectively for buccal bone augmentation presence and implant restorability after 1 year of healing. Facial bone loss of 2 mm or more was seen in 11 sites, 10 of which were full flap reflections and 1 an osteoperiosteal flap site. Implant osseointegration was 92.5% for the osteoperiosteal flaps, 93.3% for the partial-thickness flaps, and 94.4% for the full-thickness flaps. CONCLUSIONS: The 3 flap approaches to alveolar widening by crest splitting with implant placement had a sustained increased alveolar width after 1 year. However, most full flap alveolar split cases had facial bone loss and gingival recession. The osteoperiosteal flaps (book flap) and partial-thickness flaps showed stable buccal bone patterns. The results of the present clinical study of relatively early osseous remodeling suggest that full mucoperiosteal flaps should not be reflected when an alveolar split is done. However, to further elucidate the marginal bone vitality, a longer study period must be undertaken to more fully validate the alveolar split procedure and verify the best flap approach.

Le Fort I Distraction Osteogenesis of Edentulous Maxillae Combined with Simultaneous Sinus Floor Grafting to Obtain Orthoalveolar Form for Emergence Profile Dental Implant Restorations: Report of Three Patient Treatments Followed for 12 Years.

Three edentulous maxillary patients were treated with 9- to 15-mm advances of the maxilla by Le Fort I distraction osteogenesis combined with simultaneous sinus floor autograft placement. The patients were subsequently treated with 8 implants placed in the molar, bicuspid, and canine regions for complete arch ceramo-metal fixed restorations. Anterior emergence profile esthetics was obtained in 2 patients who had high smile lines. Following final restoration, no maxillary relapse was evident, and no implants were lost. Implant bone levels were stable, although 2 implants had 3 mm of bone loss over the 12-year follow-up period.