Implant Placement Using the Bone Ring Technique With and Without Membrane Placement: A Preclinical 12-Month Study in Dogs.

The bone ring technique is applied for vertical augmentation, in which the dental implant and autogenous block bone graft are simultaneously inserted. We investigated the healing of bone around implants placed simultaneously using the bone ring technique with and without membrane placement after a 12-month healing period. Vertical bone defects were created on both sides of the mandible of Beagle dogs. Implants were inserted into the defects through bone rings and fixed with membrane screws as healing caps. The augmented sites on one side of the mandible were covered with a collagen membrane. Samples were harvested 12 months after implantation and assessed histologically and by microcomputed tomography analysis. All implants remained throughout the healing period; however, except for 1 implant, they showed lost caps and/or exposure to the oral cavity. The implants had contact with newly formed bone despite frequent bone resorption. The surrounding bone appeared mature. The medians of bone volume and percentages of total bone area and bone-to-implant contact within the bone ring were slightly higher in the group with membrane placement than in that without membrane placement. Nevertheless, none of the evaluated parameters were significantly affected by the membrane placement. In the present model, soft tissue complication was frequent, and the membrane application did not reveal the effect at 12 months after implant placement using the bone ring technique. Sustained osseointegration and maturation of surrounding bone were observed in both groups after a 12-month healing period.

Comprehensive analysis and comparison of proteins in salivary exosomes of climacteric and adolescent females.

Currently, it is difficult to extract exosomes with stable physicochemical properties from saliva. Furthermore, due to inadequate availability of basic data, the application of salivary exosomes as a diagnostic material is limited. In this study, we aimed to investigate an easier method for extraction of exosomes from whole saliva and compared proteins in salivary exosomes derived from subjects of two age groups. Salivary exosomes were extracted from nine females (56.7 ± 1.17 years old; climacteric or 19.9 ± 0.20 years old; adolescent) using commercial reagents and kits and detected using western blotting with anti-exosome marker antibodies. Exosome particle size and exosome-containing proteins were identified using NanoSight® and liquid chromatography with tandem mass spectrometry, respectively. In addition, an efficient method of exosome extraction from saliva using a reagent and without the use of an ultracentrifuge was shown. Our results showed a higher total protein content and larger particle size in climacteric exosomes than in adolescent exosomes. However, adolescent exosomes showed a larger variety of proteins (780 proteins) than the climacteric exosomes (573 proteins). Altogether, 893 proteins were identified in the salivary exosomes. Although viral process-, ribosome- and structural molecule-related proteins were higher in the adolescent exosomes, the levels of major salivary proteins such as immunoglobulins and amylase, were higher in the climacteric exosomes than in the adolescent exosomes. The data presented, which show the fundamental protein composition of salivary exosomes and the changes that occur with age, are beneficial in both diagnostic and biotechnological applications.

Single-staged implant placement using the bone ring technique with and without membrane placement: Micro-CT analysis in a preclinical in vivo study.

OBJECTIVES: To assess the impact of collagen membrane application on bone formation surrounding implants placed simultaneously with the bone ring technique. MATERIAL AND METHODS: Dental implants were inserted simultaneously with the bone ring technique in standardized, vertical alveolar bony defects in the mandible of dogs. On one side of the mandible, the augmented sites were covered with a collagen membrane (M-Group). On the contralateral side, no membranes were used (NM-Group). Implants were left to heal with osseointegration for three and six months. The harvested samples were analyzed by means of micro-CT. RESULTS: A nonparametric analysis of data revealed that the membranes were not a significant negative factor for bone volume (BV), but for bone-to-implant contact (BIC, p = .04). Absence of healing caps impaired BV (p = .04) and BIC (p = .02) as well. Furthermore, loss of healing caps and exposure to the oral environment significantly and negatively affected BV (p < .001) and bone mineral density (p < .05) within 2 mm below the implant shoulder. Implant exposure and healing time had a negative interaction effect on both BV (p = .01) and BIC (p = .01). CONCLUSIONS: Within its limitations, the present study revealed no benefit of membrane application to implant placement simultaneous with the bone ring technique. Disruption of soft tissue healing was identified as a risk factor for decrease in BV and BIC.

Single-staged implant placement using bone ring technique with and without membrane placement: An experimental study in the Beagle dog.

AIM: To evaluate the impact of a collagen membrane on bone remodeling and osseointegration of implants placed simultaneously with a bone ring technique. MATERIAL AND METHODS: Standardized, vertical alveolar bone defects in the mandibles of six dogs were created. Tapered dental implants designed for two-stage subcrestal placement were inserted simultaneously with a bone ring technique. On one side of the mandible, the augmented sites were covered with a collagenous membrane. Implants with (M Group) and without membranes (NM Group) were left for an osseointegration period of 3 and 6 months, respectively. Block biopsies of the implants with surrounding bone were harvested and analyzed histologically. RESULTS: Implant exposure was a common finding (2/3) concomitantly with loss of healing caps. It appeared to be related to advanced bone loss around the implants. Exposure of implants was more frequent in M Group, however, without significant differences when compared to NM Group. The total bone area within the region of the bone ring was greater in the NM Group compared to the M Group. Moreover, in the region of the pristine bone of the M Group, the total bone was greater than at the corresponding NM Group sites at both observation periods. A nonparametric analysis of variance (ANOVA) revealed no significant effects of membrane placement or healing period on the total area of the bone. The total bone-to-implant contact (BIC) for the two groups was similar at each observation time point. However, BIC increased significantly at 6-month compared with 3-month observation period (p = .0088) in both groups. CONCLUSIONS: In vertical bone augmentation applying the bone ring technique, the disruption of soft tissue was a frequent complication. Membrane placement yielded no significant advantage on the osseointegration (BIC) of implants or bone characteristics.

Effect of Irrigation Time of Antiseptic Solutions on Bone Cell Viability and Growth Factor Release.

Antiseptic solutions are commonly utilized to treat local infection in the oral and maxillofacial region. However, surrounding vital bone is also exposed to antiseptic agents during irrigation and may have a potential negative impact on bone survival. The aim of the present study was therefore to investigate the effect of rinsing time with various antiseptic solutions on bone cell viability, as well as their subsequent release of growth factors important for bone regeneration. The bone samples collected from porcine mandible were rinsed in the following commonly utilized antiseptic solutions; povidone-iodine (0.5%), chlorhexidine digluconate (CHX, 0.2%), hydrogen peroxide (1%), and sodium hypochlorite (0.25%) for 1, 5, 10, 20, 30, or 60 minutes and assessed for cell viability and release of growth factors including vascular endothelial growth factor, transforming growth factor beta 1, bone morphogenetic protein 2, receptor activator of nuclear factor kappa-B ligand, and interleukin-1 beta by enzyme-linked immunosorbent assay. It was found in all the tested groups that the long exposure of any of the tested antiseptic solutions drastically promoted higher cell death. Sodium hypochlorite demonstrated the significantly highest cell death and at all time points. Interestingly, bone cell viability was highest in the CHX group post short-term rinsing of 1, 5, or 10 minutes when compared with the other 4 tested groups. A similar trend was also observed in subsequent growth factor release. The present study demonstrated that of the 4 tested antiseptic solutions, short-term CHX rinsing (ideally within 1 minute) favored bone cell viability and growth factor release. Clinical protocols should be adapted accordingly.

Comparison of three block bone substitutes for bone regeneration: long-term observation in the beagle dog.

This study aimed to evaluate the impact of three types of block bone substitute material on bone formation and graft resorption in vivo. Standardized bone defects (n = 4 defects/animal) were created in the calvaria of nine dogs. Block bone substitutes made of deproteinized bovine bone mineral (DBBM), beta-tricalcium phosphate (ß-TCP) and a mixture alpha-TCP and hydroxyapatite (α-TCP/HA) were inserted into the bone defects. A fourth defect was left untreated (empty). All sites were covered with a collagenous membrane. Block biopsies were harvested at 3, 6 and 12 months post-implantation and analyzed by micro-CT and histology. Biomaterial absorption was minimal and incorporation within the defect margin was good for all biomaterials. However, ß-TCP demonstrated a relatively greater volume of new bone formation and less residual material volume when compared with DBBM and α-TCP/HA. Conversely, α-TCP/HA showed higher osteoconductive potential and a greater new bone area compared with the other two biomaterials. The block bone substitutes used in the present in vivo study showed advantageous in terms of maintenance of their original form in bony defect. However, the positive impact of all biomaterials on new bone formation and replacement of bone was minor even at 12 months. These findings indicate that block bone substitutes are not well suited to vertical bone augmentation. Further investigations are required to improve the insufficient new bone volume for promising clinical results.

Presence of BPIFB1 in saliva from non-obese diabetic mice.

We previously showed that mRNA expression of BPIFB1 (Bpifb1), an antibacterial protein in the palate, lung, and nasal epithelium clone protein family, was increased in parotid acinar cells in non-obese diabetic (NOD, NOD/ShiJcl) mice, which is an animal model for Sjögren's syndrome. However, we did not previously assess the protein levels. In this report, we confirmed the expression of BPIFB1 protein in the parotid glands of NOD mice. Immunoblotting of subcellular fractions revealed that BPIBB1 was localised in secretory granules in parotid glands from NOD mice, and was almost not in parotid glands from the control mice. BPIFB1 had N-linked glycan that reacted with Aleuria aurantia lectin, which caused two types of spots with a slightly different pI and molecular weight. The expression of BPIFB1 protein was also demonstrated by immunohistochemistry. BPIFB1 was detected in the saliva from NOD mice but not in the saliva from the control mice, indicating individual constitution. BPIFB1 in saliva may be applied to other research as a diagnostic marker.

Single-staged vs. two-staged implant placement in vertically deficient alveolar ridges using bone ring technique - Part 2: implant osseointegration.

OBJECTIVES: The aim of this study was to evaluate the osseointegration of implants placed in a single-staged compared to two-staged procedure using bone ring technique. MATERIAL AND METHODS: In this study were used standardized, vertical alveolar bone defects in dogs. In the test group, dental implants (Straumann BL® , Basel, Switzerland) were inserted simultaneously with bone ring technique. As control group served implants inserted 6 months following grafting. Implants of both groups were left for an osseointegration period of 3 and 6 months. The peri-implant bone loss and bone-to-implant contact within the bone ring and native bone were analyzed morphometrically. An explorative statistical analysis was performed. RESULTS: The peri-implant bone level remained relatively stable within groups and between groups per given time period. Most of bone apposite on the implant surface in two groups was composed of newly formed bone. A nonparametric analysis of variance (ANOVA) revealed no significant advantage for two-staged implant placement for new and total bone, except for residual bone (P = .0084). Furthermore, two groups of implants performed similarly in bone ring and in native bone throughout the observation period. CONCLUSIONS: In terms of osseointegration, both techniques are likely equally efficient in the present defect model. The single-staged implant placement with cortical bone grafts warrants further documentation in clinical studies.

Effect of adhesive system application for cavities prepared with erbium, chromium: yttrium scandium gallium garnet laser on rat dental pulp tissue.

We examined the effects of adhesive systems under study applied for a laser-cut cavity using an Er,Cr:YSGG laser on rat dental pulp at 24 h and 14 days postoperatively. Group 1, laser-cut cavities were treated with a self-etching-primer and bonding agent; group 2, pretreated with a phosphoric-acid, and then treated with a self-etching-primer and bonding agent; group 3, pretreated with a phosphoric-acid and sodium-hypochlorite, and then treated with a self-etching-primer and bonding agent; and group 4, treated with an all-in-one adhesive. A flowable resin composite was used as filling material for each cavity treated with each group. A glass-ionomer-cement was used as a control. The following items were evaluated: pulp-tissue-disorganization (PTD), inflammatory-cell-infiltration (ICI), tertiary-dentin-formation (TDF), and bacterial-penetration (BP). The results were statistically analyzed using the Kruskal-Wallis test and Mann-Whitney U test. No significant differences were observed among the experimental groups for all parameters after 24 h and 14 days (P > 0.05). The majority of the specimens showed PTD with edema formation after 24 h; however, all the specimens demonstrated pulpal healing with TDF after 14 days. On the parameter of TDF, all groups showed significant differences between the two postoperative periods (P < 0.01). On the parameter of ICI, a significant difference was found between the two postoperative periods in group 4 (P < 0.05). No specimens showed BP. The pretreatment on the cavity prepared with the laser using phosphoric-acid or sodium-hypochlorite did not affect the dental pulp healing of rat tooth.

Single-staged vs. two-staged implant placement using bone ring technique in vertically deficient alveolar ridges - Part 1: histomorphometric and micro-CT analysis.

BACKGROUND: Simultaneous implant placement with bone grafting shortens the overall treatment period, but might lead to the peri-implant bone loss or even implant failure. The aim of this study was to compare the single-staged to two-staged implant placement using the bone ring technique. MATERIAL AND METHODS: Four standardized alveolar bone defects were made in the mandibles of nine dogs. Dental implants (Straumann BL® , Basel, Switzerland) were inserted simultaneously with bone ring technique in test group and after 6 months of healing period in control group. Animals of both groups were euthanized at 3 and 6 months of osseointegration period. The harvested samples were analyzed by means of histology and micro-CT. RESULTS: The amount of residual bone decreased while the amount of new bone increased up to 9 months of healing period. All morphometric parameters remained stable between 3 and 6 months of osseointegration period within groups. Per a given time point, median area of residual bone graft was higher in test group and area of new bone in control group. The volume of bone ring was greater in test than in control group, reaching the significance at 6 months of osseointegration period (P = 0.002). CONCLUSIONS: In the present type of bone defect, single-staged implant placement may be potentially useful to shorten an overall treatment period.

Characteristics of alveolar bone associated with physiological movement of molar in mice: a histological and histochemical study.

Mouse molars undergo distal movement, during which new bone is formed at the mesial side of the tooth root whereas the preexisting bone is resorbed at the distal side of the root. However, there is little detailed information available regarding which of the bones that surround the tooth root are involved in physiological tooth movement. In the present study, we therefore aimed to investigate the precise morphological differences of the alveolar bone between the bone formation side of the tooth root, using routine histological procedures including silver impregnation, as well as by immunohistochemical analysis of alkaline phosphatase and tartrate-resistant acid phosphatase activity, and immunohistochemical analysis of the expression of the osteocyte markers dentin matrix protein 1, sclerostin, and fibroblast growth factor 23. Histochemical analysis indicated that bone formation by osteoblasts and bone resorption by osteoclasts occurred at the bone formation side and the bone resorption side, respectively. Osteocyte marker immunoreactivity of osteocytes at the surface of the bone close to the periodontal ligament differed at the bone formation and bone resorption sides. We also showed different specific features of osteocytic lacunar canalicular systems at the bone formation and bone resorption sides by using silver staining. This study suggests that the alveolar bone is different in the osteocyte nature between the bone formation side and the bone resorption side due to physiological distal movement of the mouse molar.

CBCT imaging and histopathological characteristics of osteoradionecrosis and medication-related osteonecrosis of the jaw.

PURPOSE: The purpose of this study was to evaluate the cone-beam computed tomographic (CBCT) imaging and histopathological characteristics of osteoradionecrosis (ORN) and medication-related osteonecrosis of the jaw (MRONJ). MATERIALS AND METHODS: Ten surgical specimens from segmental mandibulectomy (3 ORN and 7 MRONJ) were analyzed using CBCT. The CBCT parameters were as follows: high-resolution mode (tube voltage, 90.0 kV; tube current, 4.00 mA; rotation time, 16.8 s; field of view, 56 mm×56 mm; thickness, 0.099 mm). Histopathological characteristics were evaluated using histological slides of the surgical specimens. The Pearson chi-square test was used to compare ORN and MRONJ in terms of CBCT findings (internal texture, sequestrum, periosteal reaction and cortical perforation) and histopathological characteristics (necrotic bone, inflammatory cells, reactive bone formation, bacteria, Actinomyces, and osteoclasts). A P value less than 0.05 was considered to indicate statistical significance. RESULTS: MRONJ showed periosteal reaction on CBCT more frequently than ORN (7 of 7 [100%] vs. 0 of 3 [0%], P<0.05). Regarding histopathological characteristics, MRONJ showed osteoclasts more frequently than ORN (6 of 7 [85.7%] vs. 0 of 3 [0%], P<0.05). CONCLUSION: This study evaluated the CBCT imaging and histopathological characteristics of ORN and MRONJ, and the findings suggest that CBCT could be useful for the evaluation of ORN and MRONJ.

Computer programme to assess mandibular cortex morphology in cases of medication-related osteonecrosis of the jaw with osteoporosis or bone metastases.

PURPOSE: The purpose of this study was to evaluate the morphology of the mandibular cortex in cases of medication-related osteonecrosis of the jaw (MRONJ) in patients with osteoporosis or bone metastases using a computer programme. MATERIALS AND METHODS: Fifty-four patients with MRONJ (35 with osteoporosis and 19 with bone metastases) were examined using panoramic radiography. The morphology of the mandibular cortex was evaluated using a computer programme that scanned the mandibular inferior cortex and automatically assessed the mandibular cortical index (MCI) according to the thickness and roughness of the mandibular cortex, as follows: normal (class 1), mildly to moderately eroded (class 2), or severely eroded (class 3). The MCI classifications of MRONJ patients with osteoporosis or bone metastases were evaluated with the Pearson chi-square test. In these analyses, a 5% significance level was used. RESULTS: The MCI of MRONJ patients with osteoporosis (class 1: 6, class 2: 15, class 3: 14) tended to be higher than that of patients with bone metastases (class 1: 14, class 2: 5, class 3: 0) (P=0.000). CONCLUSION: The use of a computer programme to assess mandibular cortex morphology may be an effective technique for the objective and quantitative evaluation of the MCI in MRONJ patients with osteoporosis or bone metastases.

Quantitative SPECT/CT imaging for medication-related osteonecrosis of the jaw: a preliminary study using volume-based parameters, comparison with chronic osteomyelitis.

OBJECTIVE: To investigate the quantitative SPECT/CT imaging for medication-related osteonecrosis of the jaw (MRONJ) using volume-based parameters. METHODS: Thirteen patients with mandibular lesions (nine MRONJ and four chronic osteomyelitis) underwent SPECT/CT acquisition at 4 h after injection of technetium 99m hydroxymethylene diphosphonate. Then, reconstruction of the acquired data and underwent voxel-based quantitative analysis using GI-BONE software. The parameters of the quantitative manner, such as maximum standardized uptake value (SUVmax), peak SUV (SUVpeak), mean SUV (SUVmean), metabolic bone volume (MBV) and total bone uptake (TBU), were compared for the mandibular lesions. Statistical analyses for the quantitative parameters of mandibular lesions were performed by Mann-Whitney U test. A p value lower than 0.05 was considered as statistically significant. RESULTS: Then, reconstruction of these quantitative parameters, SUVmax (10.16 ± 0.96), SUVpeak (7.95 ± 0.88), SUVmean (5.90 ± 0.86) and TBU (94.22 ± 57.44) for chronic osteomyelitis were significantly higher than those for MRONJ [5.50 ± 2.47 (p = 0.020), 4.10 ± 1.85 (p = 0.011), 2.74 ± 1.07 (p = 0.006) and 29.88 ± 15.46 (p = 0.034), respectively]. CONCLUSIONS: SUVmax, SUVpeak, SUVmean and TBU derived from bone SPECT/CT and voxel-based quantitative parameters may be useful for the evaluation of mandibular lesions, such as MRONJ and chronic osteomyelitis.

Hard and soft tissue responses to implant made of three different materials with microgrooved collar in a dog model.

The objective of the present study was to assess hard and soft tissue around dental implants made of three different materials with microgrooves on the collar surface. Microgrooved implants were inserted in the mandibles of five male beagles. Implants were made of three kinds of material; titanium (Ti), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria partially stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3). The animals were euthanatized at three months after implantation, and harvested tissue was analyzed by means of histology. All kinds of implant were osseointegrated, and there were no significant differences in any histomorphometric parameters among the three groups of microgrooved implants made of different materials. Within the limitations of this study, implants with microgrooves integrated into the surrounding bone tissue, without statistically significant differences among the three tested materials, Ti, Y-TZP, and Ce-TZP/Al2O3.

Effects of collagen membrane application and cortical bone perforation on de novo bone formation in periosteal distraction: an experimental study in a rabbit calvaria.

OBJECTIVES: The aim of the present study was to assess the impact of collagen membrane application and cortical bone perforations in periosteal distraction osteogenesis. STUDY DESIGN: A total of 32 New Zealand rabbits were randomized into four experimental groups, considering two treatment modalities. Calvarial bone was perforated or left intact (P+/-). In half the animals, the distraction mesh was covered with a collagen membrane (M+/-). All animals were subjected to a 7-day latency period and a 10-day distraction period. The samples were harvested after 4-week and 8-week consolidation periods and analyzed histologically and by means of micro-computed tomography. RESULTS: Primary, woven bone observed at the 4-week consolidation period was gradually replaced by lamellar bone at the 8-week consolidation period. Significant increase in bone volume was found in all groups (P < .001) and in bone mineral density in groups I (P-/M-; P < .001), III (P+/M-; P < .001), and IV (P+/M+; P = .013). Group III (P+/M-) showed significantly more new bone at the 8-week consolidation period compared with the other three groups (P = .001), with no differences observed in bone mineral density between groups at a given time-point. CONCLUSIONS: In the present model, cortical bone perforations have more impact on the osteogenic process compared with the application of a collagen membrane.

Hard and soft tissue responses to three different implant materials in a dog model.

The aim of this study was to assess hard and soft tissue responses using three dental implants made of different materials. Implants made of titanium (Ti), yttria-stabilized tetragonal zirconia polycrystals (Y-TZP) and ceria partially stabilized zirconia/alumina nanocomposite (Ce-TZP/Al2O3) were used in a dog model. Five male beagles were sacrificed at three months after implantation, and harvested mandible were observed and analyzed. Histological observations were similar in all groups. There were no significant differences in any histomorphometric parameters. Our results suggested the possibility of Ce-TZP/Al2O3 as a dental implant material, similar to Ti and Y-TZP.