Comparison between sandwich bone augmentation and allogenic block graft for vertical ridge augmentation in the posterior mandible.

INTRODUCTION: The purpose of this randomized controlled clinical trial was to evaluate 2 different techniques for vertical ridge augmentation (VRA) of the posterior mandible. MATERIALS AND METHODS: Sixteen subjects with 19 posterior mandibular edentulous sites requiring VRA were recruited for the study. Sites were randomly treated with either block allograft (BA; N = 9) or sandwich bone augmentation (SBA; N = 10). Clinical measurements were recorded at the time of surgery (baseline) and 6-month reentry with a custom-made acrylic surgical template. RESULTS: The mean vertical bone gain (VBG) after mean 6.8 months was 44.5% (mean = 1.78 mm [0-5 mm]) in the BA group and 33.3% (mean = 1.0 mm [-1 to 3 mm]) in the SBA group. Significantly higher rates of incision line openings and wound dehiscences were found in the BA group (n = 7/9, 77.8%) as compared with the SBA group (n = 3/10, 30%) (P = 0.037). After adjusting for graft exposure, BA group demonstrated significantly higher VBG than SBA (difference = 2.26 mm, P < 0.001). In addition, graft exposure resulted in significantly less VBG in both groups (P < 0.001). CONCLUSIONS: A higher tendency of wound exposure during VRA was demonstrated when a BA was used compared with the SBA technique. However, if wound exposure could be prevented, higher vertical ridge gain could be achieved with a BA. SUMMARY: The use of a BA in VRA resulted in a maximum of 2 mm more bone height gain compared with the SBA technique if the primary coverage can be achieved during the healing.

Influence of lateral window dimensions on vital bone formation following maxillary sinus augmentation.

PURPOSE: The aim of this study was to evaluate the influence that lateral window dimensions may have on maxillary sinus augmentation outcomes. MATERIALS AND METHODS: Patients requiring maxillary sinus augmentation by a lateral window approach and delayed implant placement were recruited in this study. Approximate window dimensions (AWD) were calculated in mm2 at the time of the surgical intervention. In all cases, a mixture of cortical and cancellous allograft particles was used as the sole grafting material. Patients were followed for 6 months. At the time of implant placement, bone core biopsies were harvested. Transversal circular samples were histomorphometrically analyzed. Proportions of vital bone (VB), remaining allograft particles (RA), and nonmineralized tissue (NMT) were quantified. Analysis of correlation of AWD with %VB, %RA, and %NMT was performed using a statistical model. RESULTS: A total of 24 maxillary sinus augmentation procedures were performed in 21 patients. One patient developed an infection after grafting and was excluded. Histomorphometric analysis showed that mean %VB was 21.69% ± 16.30%, %RA was 23.51% ± 16.33%, and %NMT was 55.08% ± 8.52%. A strong negative correlation was observed between AWD and %VB (r = -0.621; P = .0007), a marked positive correlation was found between AWD and %RA (r = 0.565; P = .002), and a minimal positive correlation, without statistical significance, was found between AWD and %NMT (r = 0.076; P = .365). CONCLUSIONS: The results of this study suggest that AWD may have an important influence on the maturation and consolidation of a mixture of cortical and cancellous allograft in the maxillary sinus.

Use of cone beam computed tomography in implant dentistry: the International Congress of Oral Implantologists consensus report.

PURPOSE: The International Congress of Oral Implantologists has supported the development of this consensus report involving the use of Cone Beam Computed Tomography (CBCT) in implant dentistry with the intent of providing scientifically based guidance to clinicians regarding its use as an adjunct to traditional imaging modalities. MATERIALS AND METHODS: The literature regarding CBCT and implant dentistry was systematically reviewed. A PubMed search that included studies published between January 1, 2000, and July 31, 2011, was conducted. Oral presentations, in conjunction with these studies, were given by Dr. Erika Benavides, Dr. Scott Ganz, Dr. James Mah, Dr. Myung-Jin Kim, and Dr. David Hatcher at a meeting of the International Congress of Oral Implantologists in Seoul, Korea, on October 6-8, 2011. RESULTS: The studies published could be divided into four main groups: diagnostics, implant planning, surgical guidance, and postimplant evaluation. CONCLUSIONS: The literature supports the use of CBCT in dental implant treatment planning particularly in regards to linear measurements, three-dimensional evaluation of alveolar ridge topography, proximity to vital anatomical structures, and fabrication of surgical guides. Areas such as CBCT-derived bone density measurements, CBCT-aided surgical navigation, and postimplant CBCT artifacts need further research. ICOI RECOMMENDATIONS: All CBCT examinations, as all other radiographic examinations, must be justified on an individualized needs basis. The benefits to the patient for each CBCT scan must outweigh the potential risks. CBCT scans should not be taken without initially obtaining thorough medical and dental histories and performing a comprehensive clinical examination. CBCT should be considered as an imaging alternative in cases where the projected implant receptor or bone augmentation site(s) are suspect, and conventional radiography may not be able to assess the true regional three-dimensional anatomical presentation. The smallest possible field of view should be used, and the entire image volume should be interpreted.

Fixed rehabilitation of severely atrophic jaws using immediately loaded basal disk implants after in situ bone activation.

Rehabilitation of severely atrophic jaws is facilitated when basal disk implants are used after activation of the future bony implant bed with a purpose-designed instrument (Osteotensor) 45 to 90 days before implant surgery. Fabrication of a highly rigid, screw-secured fixed prosthesis that acts as an external orthopedic fixator permits immediate functional loading. This protocol also represents a second chance for patients who have experienced complete implant loss and/or bone graft failure.

Long-term histopathologic evaluation of bioactive glass and human-derived graft materials in Macaca fascicularis mandibular ridge reconstruction.

OBJECTIVES: To evaluate the long-term clinical and histologic characteristics of alveolar ridge bone regenerated by 2 different types of bone graft materials in a Macaca fascicularis (nonhuman primate) species animal. METHODS: Bilateral osseous defects created in edentulous mandibular alveolar ridges in a nonhuman primate were grafted with bioactive glass (alloplast) on 1 side, and with human demineralized bone matrix (xenograft) on the contralateral side, with each covered by a dermomatrix barrier membrane before mucoperiosteal tissue flap closure and suturing. At 4 years posttreatment, surgical re-entry was performed, and bone core biopsies were obtained from each of the grafted edentulous alveolar ridges, placed in 10% formalin, and processed for light microscopic analysis. RESULTS: Normal alveolar bone was clinically noted at all sites on surgical re-entry at 4 years posttreatment, and mature cortical and cancellous bone formation was histologically observed with both types of bone graft materials. Residual bioactive glass particles (histologic sections) were found embedded in close contact with lamellar bone where bioactive glass was grafted. Xenograft-treated sites yielded remnants of residual human demineralized bone matrix particles and no foreign body reactions or inflammation. CONCLUSIONS: Numerous particles of nonresorbed bioactive glass graft material, but not human demineralized bone matrix, were found in 4-year posttreatment bone core biopsies of regenerated bone in M. fascicularis mandibular alveolar ridge reconstructions.

Hard and soft tissue changes after crestal and subcrestal immediate implant placement.

BACKGROUND: The purpose of this study is to assess the influence of the placement level of implants with a laser-microtextured collar design on the outcomes of crestal bone and soft tissue levels. In addition, we assessed the vertical and horizontal defect fill and identified factors that influenced clinical outcomes of immediate implant placement. METHODS: Twenty-four patients, each with a hopeless tooth (anterior or premolar region), were recruited to receive dental implants. Patients were randomly assigned to have the implant placed at the palatal crest or 1 mm subcrestally. Clinical parameters including the keratinized gingival (KG) width, KG thickness, horizontal defect depth (HDD), facial and interproximal marginal bone levels (MBLs), facial threads exposed, tissue-implant horizontal distance, gingival index (GI), and plaque index (PI) were assessed at baseline and 4 months after surgery. In addition, soft tissue profile measurements including the papilla index, papilla height (PH), and gingival level (GL) were assessed after crown placement at 6 and 12 months post-surgery. RESULTS: The overall 4-month implant success rate was 95.8% (one implant failed). A total of 20 of 24 patients completed the study. At baseline, there were no significant differences between crestal and subcrestal groups in all clinical parameters except for the facial MBL (P = 0.035). At 4 months, the subcrestal group had significantly more tissue thickness gain (keratinized tissue) than the crestal group compared to baseline. Other clinical parameters (papilla index, PH, GL, PI, and GI) showed no significant differences between groups at any time. A facial plate thickness ≤1.5 mm and HDD ≥2 mm were strongly correlated with the facial marginal bone loss. A facial plate thickness ≤2 mm and HDD ≥3 were strongly correlated with horizontal dimensional changes. CONCLUSIONS: The use of immediate implants was a predictable surgical approach (96% survival rate), and the level of placement did not influence horizontal and vertical bone and soft tissue changes. This study suggests that a thick facial plate, small gaps, and premolar sites were more favorable for successful implant clinical outcomes in immediate implant placement.

Mandibular nerve neurosensory impairment after dental implant surgery: management and protocol.

More than 70% of dentists have experienced patients with postoperative paresthesia/dysesthesia or anesthesia as a result of dental procedures. The most common nerve affected is the mandibular nerve, which may be injured during either implant surgery or bone grafting procedures. However, no organized protocol directed specifically for general dentists, or for the vast majority of specialists, has been published. The protocol presented in this article is divided into 5 periods: during surgery (1) nerve injury is suspected or (2) known nerve transection, post-operative period (3) 1 week and (4) 12 weeks. The appropriate treatment (pharmacology, monitoring, etc.) for each period is suggested, including the referral to a nerve specialist when appropriate.

Clinical and histologic outcomes after the use of a novel allograft for maxillary sinus augmentation: a case series.

PURPOSE: To document the clinical and histologic outcomes of sinus augmentation using a novel allogenic bone substitute as a sole grafting material. MATERIALS: Patients in need of sinus augmentation before implant placement were recruited for this study. Sinus augmentation procedures were performed following a lateral approach, using a freeze-dried allograft as the only grafting material. Patients were followed up postoperatively for 6 months. Plaque score, wound healing, and patient discomfort were recorded at each follow-up visit. Implants were placed between 6 and 7 months after sinus augmentation and restored 6 months later. Bone core biopsy specimens were harvested at the time of implant placement and processed for histologic and histomorphometrical analysis. Vital bone, remaining allograft (RA) particles, and nonmineralized tissue percentages were assessed on each sample. Results were expressed as mean percentages with SD. RESULTS: Of the 23 sinus patients, 20 patients underwent sinus augmentation surgery. All patients had satisfactory postoperative healing in the absence of complications. A total of 39 implants were placed. One implant failed and was replaced 3 months later. Histologic analysis revealed the presence of well-organized lamellar bone, in direct contact with RA particles. Mean vital bone was 23.02 +/- 19.11%, mean RA was 22.25 +/- 20.30%, and average nonmineralized tissue was 54.73 +/- 13.51%. CONCLUSION: Clinical and histologic findings support the suitability of an allograft consisting of a combination of cortical and cancellous chips for sinus augmentation procedures.

The influence of the bucco-palatal distance on sinus augmentation outcomes.

BACKGROUND: Maxillary sinus augmentation is one of the most reliable implant site development options to increase vertical bone height. However, graft consolidation requires adequate angiogenesis and migration of cells involved in osteogenesis and bone remodeling. It is speculated that these biologic events are greatly determined by the dimensions of the maxillary sinus cavity. Hence, the purpose of this study is to assess the influence of the distance from the lateral to the medial wall of the maxillary sinus on the outcomes of sinus augmentation procedures. METHODS: A total of 25 patients in need of sinus augmentation were recruited for the study. After initial examination, customized radiographic and surgical guides were fabricated and a cone-beam computerized tomography scan was obtained per patient. The bucco-palatal distance (BPD) was measured at 8, 10, and 12 mm from the alveolar crest. Sinus grafting was performed by a lateral window approach using a particulated allograft material. Patients were followed-up for 6 months. At the time of implant placement, bone core biopsies were harvested using the radiographic-surgical guide. Sections of the bone cores at 8, 10, and 12 mm from the alveolar crest were histomorphometrically analyzed. The proportion of vital bone (%VB) was correlated with the BPD using a statistical model. RESULTS: Twenty-one patients underwent sinus augmentation for a total of 24 sinuses; however, the data analyzed contained only one sinus per patient. One sinus developed an infection after grafting, resulting in a 96% success rate for the sinus grafting procedure. Twenty sinuses were used in the final statistical analysis. Histomorphometric analysis revealed that mean %VB was 22.71 +/- 19.08, mean percent of remaining allograft was 23.39 +/- 20.85, and average percent of non-mineralized connective tissue was 53.90 +/- 13.23. Analysis of the correlation between %VB and BPD by linear regression, using the actual values of BPD showed a strong negative association (R(2) = 0.141; P <0.001). CONCLUSION: The findings suggest that the %VB formation after maxillary sinus augmentation is inversely proportional to the sinus BPD.

A novel decision-making process for tooth retention or extraction.

BACKGROUND: Implant-supported restorations have become the most popular therapeutic option for professionals and patients for the treatment of total and partial edentulism. When implants are placed in an ideal position, with adequate prosthetic loading and proper maintenance, they can have success rates >90% over 15 years of function. Implants may be considered a better therapeutic alternative than performing more extensive conservative procedures in an attempt to save or maintain a compromised tooth. Inadequate indication for tooth extraction has resulted in the sacrifice of many sound savable teeth. This article presents a chart that can assist clinicians in making the right decision when they are deciding which route to take. METHODS: Articles published in peer-reviewed English journals were selected using several scientific databases and subsequently reviewed. Book sources were also searched. Individual tooth- and patient-related features were thoroughly analyzed, particularly when determining if a tooth should be indicated for extraction. RESULTS: A color-based decision-making chart with six different levels, including several factors, was developed based upon available scientific literature. The rationale for including these factors is provided, and its interpretation is justified with literature support. CONCLUSION: The decision-making chart provided may serve as a reference guide for dentists when making the decision to save or extract a compromised tooth.

Posterior implant single-tooth replacement and status of adjacent teeth during a 10-year period: a retrospective report.

BACKGROUND: The purpose of this case series study was to evaluate posterior single-tooth implant survival and the long-term conditions of the adjacent teeth. METHODS: A retrospective evaluation of 1,162 consecutive patients with a single missing posterior tooth treated with 1,377 external hex implants supporting 1,365 restorations surrounded by natural teeth over a 1- to 10-year period was reviewed from four private offices. Implant survival data were collected relative to stage I to stage II healing, stage II to prosthesis delivery, and prosthesis delivery to up to 10 years of follow-up. Long-term adjacent tooth conditions were assessed, including decay, endodontic therapy (root canal therapy [RCT]), and/or extraction during the follow-up period. RESULTS: Of the 1,377 implants inserted, there were 11 surgical failures from stage I to stage II healing. There was one failure from stage II healing to prosthesis delivery. There were two prosthetic-phase failures. The surgical success rate was 99.2%, whereas the overall survival rate was 98.9% at an average of 61 months of follow-up (range, 12 to 125 months). A total of 2,589 adjacent teeth were followed during the study. No natural adjacent tooth was lost during this period. Interproximal decay developed in 129 adjacent teeth (5%), and nine adjacent teeth required RCT (0.4%) as a result of decay or restoration. CONCLUSIONS: The use of single-tooth implants as replacements for posterior missing teeth is a viable long-term treatment. Adjacent natural teeth complications are minimal for as long as 10 years after implant insertion.

Atraumatic extractions: a biomechanical rationale.

Biomechanical aspects of force have been applied to tooth extraction for centuries. However, the mechanical advantages available to extract the teeth were primarily applied to hold the crown of the tooth, rather than help extract it. An extraction device (Physics Forceps) has been developed to apply a biomechanical rationale to the extraction process of a tooth using a class 1 lever, creep, and shear components of force.

Implant success, survival, and failure: the International Congress of Oral Implantologists (ICOI) Pisa Consensus Conference.

The primary function of a dental implant is to act as an abutment for a prosthetic device, similar to a natural tooth root and crown. Any success criteria, therefore, must include first and foremost support of a functional prosthesis. In addition, although clinical criteria for prosthetic success are beyond the scope of this article, patient satisfaction with the esthetic appearance of the implant restoration is necessary in clinical practice. The restoring dentist designs and fabricates a prosthesis similar to one supported by a tooth, and as such often evaluates and treats the dental implant similarly to a natural tooth. Yet, fundamental differences in the support system between these entities should be recognized. The purpose of this article is to use a few indices developed for natural teeth as an index that is specific for endosteal root-form implants. This article is also intended to update and upgrade what is purported to be implant success, implant survival, and implant failure. The Health Scale presented in this article was developed and accepted by the International Congress of Oral Implantologists Consensus Conference for Implant Success in Pisa, Italy, October 2007.

Guidelines for maxillary incisal edge position-a pilot study: the key is the canine.

PURPOSE: The purpose of this pilot study was to evaluate the relationship between the vertical position of the maxillary central incisal edge and the maxillary canine relative to the maxillary lip line in repose of dentate patients. This may be beneficial for clinicians in establishing guidelines for the rehabilitation of edentulous patients. MATERIALS AND METHODS: One hundred and four Caucasian dentate patients (59 men and 45 women) between the ages of 30 and 59 years were evaluated. A millimeter ruler was used to measure the maxillary right central incisor edge and the maxillary right canine tip to the maxillary lip in repose. Data were collected in reference to sex and age. RESULTS: For the female group, average central incisor exposure in relation to the relaxed maxillary lip line was 3.8 mm, and the range of exposure was -1 to +8 mm. In the 30- to 39-year olds (17 patients), the average was 4.1 mm with a range of 0 to 8 mm. The average in the 40- to 49-year-old group (16 patients) was 2.8 mm with a range of -1 to +6 mm. In 50- to 59-year olds (12 patients), the average was 1.8 mm with a range of -1 to +5 mm. In the male group, the average central incisor exposure was 2.5 mm, and the range was -3 to +7 mm. The average for the 30- to 39-year-old group (20 patients) was 3.2 mm with a range of 0 to 7 mm. For the 40- to 49-year group (18 patients), the average was 2.4 mm and for 50 to 61 years (21 patients), it was 1.4 mm with a range of -3 to +5 mm in both latter age groups. The canine position for the female group average exposure was 0 mm, with a range of -2 to +2 mm. For the 30- to 39-year old group, average exposure was 1 mm with a range of -1 to +2 mm. The 40- to 49-year-old group exposed an average of 0.4 mm with a range of -1 to +2 mm. For the 50- to 59-year old group, canine exposure was -0.5 mm with a range of -2 to +1 mm. The male average canine exposure was -0.5 mm, and the range was -3 to +2 mm. For the 30- to 39-year old group, the average was 0.9 mm with a range of -1 to +2 mm. The 40- to 49-year-old group exposed an average of 0.2 mm, with a range of -1 to +2 mm. For the 50- to 59-year old group, average was -0.9 mm with a range of -2 to +1 mm. CONCLUSIONS: There was a large range of maxillary central incisal exposure in relation to the maxillary lip line. The average dimension of central incisor exposure represented less than 30% of the subjects in the study and could not be used predictably to assess incisal edge position. The range of canine exposure was narrower. The average dimensions of canine exposure to the lip were within 1 mm for both men and women in all age groups. Further studies are needed to confirm these preliminary results. The average dimensions for the different sex and age groups related to canine exposure represented a greater proportion of the subjects. Therefore, it is suggested that the average canine exposure dimension can be used clinically to assess anterior incisor edge position when restoring edentulous patients.