A Review of Sinus Floor Elevation Techniques: Lateral Window, Transcrestal, Graft Materials, and Biologics.

Various approaches to implant placement in the atrophic posterior maxilla are currently advocated in the literature. Such strategies range from the use of block bone graft, to short, tilted, and zygomatic implants, to sinus floor elevation (SFE). SFE has shown to be a predictable surgical procedure to increase bone height in the posterior maxilla. This article provides a narrative overview of SFE techniques, including a modified localized management of sinus floor technique in fresh molar extraction sockets.

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.

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.

Guided Nitinol-Retained (Smileloc) Single-Tooth Dental Restorations.

Nitinol metal alloy that changes shape according to temperature has been in clinical use at select clinics worldwide for the past 2 years and is now released for general use. The Smileloc Abutment and nitinol sleeve enable "cementless," "screwless," crown fastening that saves time and cost with the prospect of replacement of much of the present, sometimes troublesome, anthropic, soon to be anachronistic, technology.

Computer Simulation and Maxillary All-on-Four Surgery.

Maxillary all-on-four implant reconstruction requires training beyond normal dental implant training. It conjoins technical surgical acumen, anatomic and complex spatial relationship understanding, thorough awareness of dental prosthodontic principles, and excellent patient management skills. Acquisition of appropriate training to the level of competence in an era of greater patient expectations and increased vigilance for patient safety and overall quality of care is limited. Repeated purposeful practice in performing complex psychomotor tasks is of paramount importance in achieving competence. Surgical simulation may assist surgical learners to acquire familiarity with relevant anatomic variations, instrumentation, surgical techniques, and management of intraoperative and postoperative complications.

Vertical Alveolar Augmentation Using BMP-2/ACS/Allograft with Printed Titanium Shells to Establish an Early Vascular Scaffold.

Traditional reconstruction of major alveolar ridge deficiency has required autogenous cortical cancellous particulate bone grafts, often augmented with particulate allogeneic components. Now there is a new concept to consider, that of orthoalveolar form. This paradigm shift involves components of the tissue engineering triad of inductive growth factors combined with a matrix and stem cells, together with osteotomies or devices designed for space maintenance. Reported here is early experience with computer technology used to redesign deficient alveolar ridges deriving ideal alveolar-shaped bone-forms made from powdered titanium, sintered by laser at high temperature using rapid prototype technology.

Shape-Memory Retained Complete Arch Guided Implant Treatment Using Nitinol (Smileloc) Abutments.

A case report of a complete arch interim prosthesis executed using digital work flows and with guided implant surgery is presented. The novel shape-memory retained system used to retain the complete dental prosthesis is easily indexed onto the remaining dentition, thereby being both efficient and cost-effective in the short and long term.

Computer Simulation Training for Mandibular All-on-Four/All-on-Three Surgery.

Mandibular all-on-4 implant reconstruction techniques are less complex than maxillary but more complex than routine dental implant surgery, requiring advanced technical skills, deeper understanding of prosthodontic principles, and more complex surgical planning. Surgical simulation may assist experienced surgeons seeking to acquire new skills through increased planning ability, improved intraspecialty communication, and enhanced technical competence. Achieving competence is different for the trainee devoted to the learning process and the practicing surgeon with limited time and balancing other roles and responsibilities. Well-constructed continuing education incorporating simulation, 3-dimensional printed models, and computer-assisted planning may offer the most efficient path to competence.

Extra-Long Nasal Wall-Directed Dental Implants for Maxillary Complete Arch Immediate Function: A Pilot Study.

Immediate loading of maxillary denture prostheses in the context of severe bone atrophy is complicated by posterior implant placement, sometimes requiring a complex surgical approach as zygomatic or pterygoid implants. To overcome this complexity, the authors developed an extra-long (20-24 mm) 24-degree angulated platform. It was tested on 33 patients, with 24 patients immediately loaded (72.7%) for a total of 115 implants (46% nasal). All delayed loading implants osseointegrated. Eight bilateral and six unilateral sinus grafts were performed. There were no complications during the follow-up period.

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.

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.

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.

Dental extraction, immediate placement of dental implants, and immediate function.

Immediate function requires adequate implant stability. Immediate function requires prosthetic stability, particularly when multiple implants are loaded. Factors to consider for immediate implants into extraction sites are thickness of socket walls, thickness of gingival drape, optimal position of the implant, and patient factors such as hygiene and smoking cessation.

Vertical bone augmentation using recombinant bone morphogenetic protein, mineralized bone allograft, and titanium mesh: a retrospective cone beam computed tomography study.

PURPOSE: This retrospective study evaluated the use of a composite graft of recombinant human bone morphogenetic protein-2 (rhBMP-2) and particulate mineralized bone allograft protected by a titanium mesh for vertical bone augmentation. MATERIALS AND METHODS: A review of data on patients from four oral and maxillofacial surgery practices in the United States who required vertical augmentation prior to implant treatment was conducted. Vertical augmentation was accomplished with rhBMP-2 in an absorbable collagen sponge (ACS) carrier and particulate allograft. Cone beam computed tomography was used to measure vertical bone gains using this technique. RESULTS: Sixteen vertical ridge augmentation procedures were performed in 15 patients. The maximum vertical bone gains ranged from 4.4 to 16.3 mm. The average maximum vertical bone gain was 8.53 mm. The procedure allowed implant placement in all patients. Forty implants were inserted into the grafted ridges after a minimum of 6 months of healing. All implants integrated and were used for prosthetic support. CONCLUSION: This study suggests that rhBMP-2/ACS and particulate mineralized bone allograft protected by a titanium mesh offers favorable vertical bone gains to allow dental implant placement.

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.

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.