Mesiodistal Measurements for Dental Implant Planning: A Prospective Clinical Study of Linear Measurements on Cone-Beam Computed Tomography Images in Comparison with Caliper-Based Measurements on Plaster Casts.

Althouh cone beam computed tomography (CBCT) is popular for dental implant planning, the horizontal mesiodistal space of the edentulous ridge is still conventionally measured with a handheld sliding caliper in the oral cavity or on a plaster cast. For clinical application in implant planning, our aim was to evaluate the accuracy of CBCT horizontal mesiodistal linear measurements in comparison with conventionally obtained direct measurements on plaster casts. Postoperative CBCT acquisitions and plaster casts of 27 patients with adjacent posterior mandibular implants were analyzed in a prospective clinical study. On CBCT images, two observers assessed the inter-implant distances on axial and sagittal views. On plaster casts, the inter-implant distances were measured with a digital caliper. CBCT measurements on axial and sagittal views were, on average, 0.2 mm larger than measurements on plaster casts. Correlation was perfect between measurements of the same inter-implant distance performed by the observers on CBCT images and on plaster casts. When compared with conventionally obtained direct measurements on plaster casts, CBCT views slightly overestimated (mean 0.2 mm) the horizontal mesiodistal measurements between two implants as reference points. CBCT imaging is sufficiently accurate to evaluate mesiodistal distances on axial and sagittal views for dental implant planning in clinical practice.

Allopurinol-Induced Oral Lichenoid Drug Reaction with Complete Regression after Drug Withdrawal.

Background: Lichen planus is a chronic mucocutaneous inflammatory disease. Oral manifestations are common, and may remain exclusive to the oral mucosa without involvement of the skin or other mucosae. A differential diagnosis includes oral lichenoid drug reactions. Allopurinol, which is the first line hypo-uricemic treatment, is often quoted as being a possible offending drug, though oral reactions have rarely been reported. Case presentation: We describe a 59-year-old male gout patient, successfully treated with allopurinol, who developed acute onset of oral lichenoid lesions, involving bilaterally the buccal mucosa, the tongue and the labial mucosa. Histopathology was consistent with a lichen planus or a drug-induced lichenoid reaction. Improvement of the patient's condition after withdrawal of allopurinol confirmed the lichenoid nature of the lesion. Remission was complete after a few weeks. Discussion: Although unusual, allopurinol may induce a lichenoid drug reaction. These reactions may mimic clinically and histopathologically idiopathic lichen planus. Improvement or complete regression of the lesions may be attempted to confirm the diagnosis. According to the latest WHO recommendations, these lesions have a potential for malignant transformation.

Large Bone Vertical Augmentation Using a Three-Dimensional Printed TCP/HA Bone Graft: A Pilot Study in Dog Mandible.

BACKGROUND: Osteoflux is a three-dimensional printed calcium phosphate porous structure for oral bone augmentation. It is a mechanically stable scaffold with a well-defined interconnectivity and can be readily shaped to conform to the bone bed's morphology. PURPOSE: An animal experiment is reported whose aim was to assess the performance and safety of the scaffold in promoting vertical growth of cortical bone in the mandible. MATERIALS AND METHODS: Four three-dimensional blocks (10 mm length, 5 mm width, 5 mm height) were affixed to edentulous segments of the dog's mandible and covered by a collagen membrane. During bone bed preparation, particular attention was paid not to create defects 0.5 mm or more so that the real potential of the three-dimensional block in driving vertical bone growth can be assessed. Histomorphometric analyses were performed after 8 weeks. RESULTS: At 8 weeks, the three-dimensional blocks led to substantial vertical bone growth up to 4.5 mm from the bone bed. Between 0 and 1 mm in height, 44% of the surface was filled with new bone, at 1 to 3 mm it was 20% to 35%, 18% at 3 to 4, and ca. 6% beyond 4 mm. New bone was evenly distributed along in mesio-distal direction and formed a new crest contour in harmony with the natural mandibular shape. CONCLUSIONS: After two months of healing, the three-dimensional printed blocks conducted new bone growth above its natural bed, up to 4.5 mm in a canine mandibular model. Furthermore, the new bone was evenly distributed in height and density along the block. These results are very promising and need to be further evaluated by a complete powerful study using the same model.

A 3D printed TCP/HA structure as a new osteoconductive scaffold for vertical bone augmentation.

INTRODUCTION: OsteoFlux(®) (OF) is a 3D printed porous block of layered strands of tricalcium phosphate (TCP) and hydroxyapatite. Its porosity and interconnectivity are defined, and it can be readily shaped to conform the bone bed's morphology. We investigated the performance of OF as a scaffold to promote the vertical growth of cortical bone in a sheep calvarial model. MATERIALS AND METHODS: Six titanium hemispheres were filled with OF, Bio-Oss (particulate bovine bone, BO), or Ceros (particulate TCP, CO) and placed onto the calvaria of 12 adult sheep (6 hemispheres/sheep). Histomorphometric analyses were performed after 8 and 16 weeks. RESULTS: OF led to substantial vertical bone growth by 8 weeks and outperformed BO and CO by a factor 2 yielding OF 22% ± 2.1; BO 11.5% ± 1.9; and CO 12.9% ± 2.1 total new bone. 3 mm away from the bony bed, OF led to a fourfold increase in new bone relative to BO and CO (n = 8, P < 0.002). At 16 weeks, OF, BO, and CO behaved similarly and showed marked new bone synthesis. A moderate degradation was observed at 16 weeks for all bone substitutes. CONCLUSION: When compared to existing bone substitutes, OF enhances vertical bone growth during the first 2 months after implantation in a sheep calvarial model. The controlled porous structure translated in a high osteoconductivity and resulted in a bone mass 3 mm above the bony bed that was four times greater than that obtained with standard substitutes. These results are promising but must be confirmed in clinical tests.

Influence of image-viewers and artifacts on implant length measurements in cone-beam computed tomography: an in vitro study.

This preclinical in vitro study compared the accuracy of implant lengths measured in two different image-viewers, and examined whether implant-induced artifacts affected the implant length measurements on CBCT images. A resin edentulous mandibular model, with multiple adjacent implants in the posterior segments, was acquired with a CBCT machine. In two different image-viewers, two observers independently measured the implant length. Vertical measurements on CBCT images were carried out twice at each session, and repeated one week later. The results demonstrated no significant differences between actual and measured implant lengths. The differences in the mean error for vertical measurements using the two different image-viewers (cross-sectional images: OsiriX viewer = -0.01 ± 0.03 mm, NewTom viewer = -0.05 ± 0.09 mm, p-value = 0.056; sagittal images: OsiriX viewer = -0.03 ± 0.04 mm; NewTom viewer = -0.04 ± 0.10 mm, p-value = 0.24) were not statistically significant. This in vitro investigation suggests that the accuracy of implant length measurements on CBCT images was not influenced by image-viewers or by the presence of implant-induced artifacts. The presence of multiple adjacent implants in the posterior segments of the mandible is not likely to impact the measurements made between the implant apex and vital structures on CBCT images.

Maxillary sinus grafting with a synthetic, nanocrystalline hydroxyapatite-silica gel in humans: histologic and histomorphometric results.

The aim of this study was to evaluate in humans the amount of new bone after sinus floor elevation with a synthetic bone substitute material consisting of nanocrystalline hydroxyapatite embedded in a highly porous silica gel matrix. The lateral approach was applied in eight patients requiring sinus floor elevation to place dental implants. After elevation of the sinus membrane, the cavities were filled with 0.6-mm granules of nanocrystalline hydroxyapatite mixed with the patient's blood. A collagen membrane (group 1) or a platelet-rich fibrin (PRF) membrane (group 2) was placed over the bony window. After healing periods between 7 and 11 months (in one case after 24 months), 16 biopsy specimens were harvested with a trephine bur during implant bed preparation. The percentage of new bone, residual filler material, and soft tissue was determined histomorphometrically. Four specimens were excluded from the analysis because of incomplete biopsy removal. In all other specimens, new bone was observed in the augmented region. For group 1, the amount of new bone, residual graft material, and soft tissue was 28.7% ± 5.4%, 25.5% ± 7.6%, and 45.8% ± 3.2%, respectively. For group 2, the values were 28.6% ± 6.90%, 25.7% ± 8.8%, and 45.7% ± 9.3%, respectively. All differences between groups 1 and 2 were not statistically significant. The lowest and highest values of new bone were 21.2% and 34.1% for group 1 and 17.4% and 37.8% for group 2, respectively. The amount of new bone after the use of nanocrystalline hydroxyapatite for sinus floor elevation in humans is comparable to values found in the literature for other synthetic or xenogeneic bone substitute materials. There was no additional beneficial effect of the PRF membrane over the non-cross-linked collagen membrane.

Relevance of surgical management of patients affected by bisphosphonate-associated osteonecrosis of the jaws. A prospective clinical and radiological study.

OBJECTIVES: Actually, consensus management of osteonecrosis of the jaws (ONJ) related to nitrogen-containing bisphosphonates (NBPs) is mostly a conservative approach. It does not always control the symptoms and the progression of the disease. The aim of this study was to evaluate the clinical and radiological outcomes of three therapeutic management strategies of established ONJ. MATERIALS AND METHODS: Three treatment strategies, i.e., conservative approach, minimal invasive surgery, and extensive surgery were evaluated in 39 ONJ patients treated with NBPs for malignant diseases or osteoporosis. The patients were closely monitored, and the outcome (extension, improvement, or healing) of mucosa and bone was clinically and radiographically evaluated on a long-term period (27.05 ± 2.96 months). RESULTS: Primary pathology (osteoporosis or malignancies) and clinical severity of ONJ (mild, moderate, severe) were decisive factors. Osteoporotic patients showed more frequently complete mucosa or bone healing (p = 0.0128 and p = 0.00021, respectively) than malignant patients. Mucosa closure and bone improvement occurred more in mild ONJ patients than in severe ONJ (p = 0.0053 and p = 0.0319, respectively). Treatment strategy appeared to be a crucial factor for mucosa but not for bone healing. The rate of complete mucosa healing increased after an extensive surgical procedure (p = 0.0096). CONCLUSIONS: A surgical management of patients with ONJ positively influenced the clinical outcome by enhancing mucosa healing. CLINICAL RELEVANCE: These results deserve further investigations involving a larger cohort. However, they strongly suggest that the guidelines of management of patients with ONJ related to NBPs have to be reconsidered.

Potential adverse events of endosseous dental implants penetrating the maxillary sinus: long-term clinical evaluation.

OBJECTIVES/HYPOTHESIS: The aim of this study was to evaluate the nature and incidence of long-term maxillary sinus adverse events related to endosseous implant placement with protrusion into the maxillary sinus. STUDY DESIGN: Retrospective cohort study. METHODS: All patients who underwent placement of endosseous dental implants with clinical evidence of implant penetration into the maxillary sinus with membrane perforation were included in this study. Only patients with a minimum follow-up of 5 years after implant placement were included in this study. Maxillary sinus assessment was both clinical and radiological. RESULTS: Eighty-three implants with sinus membrane perforation in 70 patients met the study's inclusion criteria. Mean age was 65.96 years ± 14.23. Twelve patients had more than one implant penetrating the maxillary sinus, and seven of them had bilateral sinus perforation. Estimated implant penetration was ≤ 3 mm in all cases. The average clinical and radiological follow-up was 9.98 years ± 3.74 (range 60-243 months). At the follow-up appointments, there were no clinical or radiological signs of sinusitis in any patient. CONCLUSION: This long-term study, spreading over a period of up to 20 years, indicates that no sinus complication was observed following implant penetration into the maxillary sinus. Furthermore, absence of occurrence of such complications is related to the maintenance of successful osseointegration. A contrario, and in the presence of an acute or chronic maxillary sinusitis, the differential diagnosis must always consider other potential odontogenic and nonodontogenic etiologies.

Rehabilitation of the edentulous posterior maxilla after sinus floor elevation using deproteinized bovine bone: a 9-year clinical study.

OBJECTIVES: To evaluate the long-term survival rate of rough-surfaced implants placed in maxillary sinuses augmented with deproteinized bovine bone (Bio-Oss; Geistlich Pharma AG, Wolhusen, Switzerland). MATERIALS AND METHODS: Thirteen maxillary sinuses were augmented in 10 patients with Bio-Oss. After an average healing period of 13.8 months, 24 implants were placed. In 4 cases, biopsies were performed and submitted to histological analysis. Clinical and radiographic evaluation was performed 9 years after implant placement and minimum 8 years after functional loading. RESULTS: At the 9-year control, all the 24 implants were still functional. Thus, the implant survival rate was 100%. CONCLUSIONS: Bio-Oss is an acceptable substitute to the autogenous bone, and it can be used as a unique material for sinus floor elevation. Rough-surfaced implants placed in 100% Bio-Oss grafts showed a high survival rate (100%) on the long term. Larger clinical trials are necessary to confirm our results.

Graft shrinkage and survival rate of implants after sinus floor elevation using a nanocrystalline hydroxyapatite embedded in silica gel matrix: a 1-year prospective study.

OBJECTIVES: The aims of this study were (1) to evaluate the vertical shrinkage percentage of nanocrystalline hydroxyapatite embedded in silica gel used for maxillary sinus floor elevation (SFE) and (2) to determine the survival rate of the implants 1 year after placement in the healed grafted sinuses. MATERIALS AND METHODS: Eleven maxillary sinuses were augmented in eight patients with NanoBone. After a healing period averaging 14.42 months, 19 implants were placed and followed up with clinical and radiographic evaluation. Panoramic radiographs were taken immediately after SFE and at 12 months after grafting. Measurements of changes in height were made by a computerized measuring technique using an image editing software. RESULTS: The mean graft height shrinkage percentage at 12 months after surgery was 8.84% (±5.32). One implant was lost before loading. All the 18 remaining osseointegrated implants received the prosthetic rehabilitation and were controlled after 3 months of functional loading. The implant survival rate at the 1-year interval was 94.74%. CONCLUSIONS: A 100% NanoBone alloplastic graft used in lateral SFE procedures presented limited height shrinkage. Implants placed in these grafted sinuses showed survival rates similar to those found in published data. These results should be interpreted cautiously considering the study's reduced sample size.

Bisphosphonate-associated osteonecrosis of the jaw: a key role of inflammation?

Osteonecrosis of the jaw (ONJ) can be associated with nitrogen-containing bisphosphonates (NBPs) therapy. Various mechanisms of NBP-associated ONJ have been proposed and there is currently no consensus of the underlying pathogenesis. The detailed medical and dental histories of 30 ONJ patients treated with NBPs for malignant diseases (24) or osteoporosis (6) were analyzed. The necrotic bone was resected and analyzed histologically after demineralization. In 10 patients the perinecrotic bone was also resected and processed without demineralization. Alveolar bone samples from 5 healthy patients were used as controls. In 14 ONJ patients, serial technetium-99m-methylene diphosphonate scintigraphic scans were also available and confronted to the other data. Strong radionuclide uptake was detected in some patients several months before clinical diagnosis of ONJ. The medullary spaces of the necrotic bone were filled with bacterial aggregates. In the perinecrotic bone, the bacteria-free bone marrow characteristically showed an inflammatory reaction. The number of medullary inflammatory cells taken as an index of inflammation allowed us to discriminate two inflammation grades in the ONJ samples. Low-grade inflammation, characterized by marrow fibrosis and low inflammatory cells infiltration, increased numbers of TRAP(+) mono- and multineacleated cells was seen in patients with bone exposure<2 cm(2). High-grade inflammation, associated with larger lesions, showed amounts of tartrate-resistant acid phosphatase(+)/calcitonin receptor(-) mono- and multinucleated cells, osteocyte apoptosis, hypervascularization and high inflammatory cell infiltration. The clinical extent of ONJ was statistically linked to the numbers of inflammatory cell. Taken together these data suggest that bone necrosis precedes clinical onset and is an inflammation-associated process. We hypothesize that from an initial focus, bone damage spreads centrifugally, both deeper into the jaw and towards the mucosa before the oral bone exposure and the clinical diagnosis of ONJ.