Would Be Prophylactic Administrations of Low Concentration of Alendronate an Alternative for Improving the Craniofacial Bone Repair? A Preliminary Study Focused in the Period of Cellular Differentiation and Tissue Organization.

BACKGROUND: Alendronate (ALN) is a nitrogen-bisphosphonate that may induce an anabolic effect on craniofacial bone repair when administrated in low doses. Based on this premise, this study analyzed the influence of prophylactic low doses of ALN on bone healing in defects created in rabbit mandible. METHODS: A 5 × 2-mm diameter deep defect was created in the calvaria of 28 rabbits. Fourteen of these rabbits received previously 50 µg/kg of 1% sodium ALN for 4 weeks, while the other rabbits received only 0.9% physiological saline solution (control). Animals were euthanized at 15 and 60 days postsurgery (n = 7), and the data were analyzed using histomorphometry and immunohistochemistry using the anti-CD34, bone morphogenetic protein -2 (BMP-2), and transforming growth factor (TGF)-ß1 antibodies. RESULTS: On the 15th day postsurgery, the specimens that received previous treatment with ALN demonstrated large vascular lumen and intense positivity to CD34 either concentrated in endothelium or cells spread among the reparative tissue. These results coincided with intense positivity for BMP-2+ cells and TGF-ß1 that was concentrated in both cells and perivascular area. In contrast, the control group revealed scarce cells that exhibited CD34, BMP-2+, and the TGF-ß1 was restricted for perivascular area on well-formed granulation tissue. These patterns of immunohistochemical result, especially found on the 15th day of analysis, seem to be responsible for the development of larger quantities of bone matrix in the specimens that receive ALN on the 60th day postsurgery. CONCLUSION: These preliminary results showed that the prophylactic administration of low doses of ALN might be an alternative to craniofacial bone craniofacial bone repair because it increases the immunopositivity for TGF-ß1 and consequently improves the CD34+ and BMP-2+ cells on reparative sites.

Effect of alendronate on the progression of periodontitis induced by Porphyromonas gingivalis and Fusobacterium nucleatum: a study in rats.

OBJECTIVE: The study aimed to investigate the effect of alendronate (ALN) on the inhibition of alveolar bone loss in experimental periodontitis in Wistar rats. MATERIALS AND METHODS: Periodontitis was induced by oral inoculation of Porphyromonas gingivalis with Fusobacterium nucleatum. The rats (n = 80) were randomized as follows: negative control (n = 10); positive control (n = 10); ALN groups: test 8 (n = 10), test 12 (n = 10), and test 16 (n = 10); and placebo groups: control 8 (n = 10), control 12 (n = 10), and control 16 (n = 10). Two milligrams per kilogram of ALN or placebo was administered twice weekly for 8, 12, and 16 weeks. Bone loss was determined by morphological and histological analyses. One independent, blinded examiner (ICC, 0.91) performed the measurements. The distance from the cement enamel junction to the alveolar bone crest of the second lower molar was measured: distal-vestibular (d), furca (f), mesial-vestibular (h), and area. Histometry was performed on the second contralateral molar. Sections (6 µm) were used to determine the furcation bone area (A-FB). The following statistical analyses were conducted: Mann-Whitney and Kruskal-Wallis. RESULTS: PC group developed periodontitis (p < 0.0001). Morphometric analysis determined that ALN was effective in T8 for linear measurements d, f, and h (p < 0.05). No significant differences occurred at test 8, test 12, and test 16. Analysis of A-FB revealed no significant differences between the ALN and placebo groups at 8 and 16 weeks (p > 0.05). ALN was effective against bone loss in relation to A-FB after 12 weeks (p < 0.0001). CONCLUSIONS: According to the methodology used, the results suggest that oral administration of ALN could influence alveolar bone loss in rats submitted to experimental periodontitis. CLINICAL RELEVANCE: ALN could be a potential therapeutic approach when associated with periodontal treatment.

Influence of Metal and Ceramic Abutments on the Stress Distribution Around Narrow Implants: A Photoelastic Stress Analysis.

PURPOSE: This study aimed to compare, through photoelastic analysis, the distribution of stresses around narrow implants with external hexagon (EH) and Morse taper (MT) connections, when single crowns made with metal and ceramic abutments were used. MATERIALS AND METHODS: Six photoelastic models were prepared, simulating the use of narrow EH and MT implants replacing a lateral incisor. These 2 groups received 3 different abutments: prefabricated metal abutments, customized metal abutments, and customized zirconia abutments. All crowns were identical and made with a leucite reinforced glass-ceramic. Vertical loads of 0 to 100 N were applied on the palatal surface of the crowns, and the photoelastic stress fringes developed in each model were captured in a high-definition video, and digital photographs were taken at 100 N. RESULTS: The abutment type and material influenced the stress distribution patterns around narrow implants with EH and MT connections. Stresses were generated mainly around the apical and lingual regions of the implants. CONCLUSIONS: For both connections, the prefabricated metal abutments presented better stress distribution around the implants when compared to customized metal and zirconia abutments because low stress levels were developed in smaller areas around the implants.

Tissue reaction of deproteinized bovine bone matrix grafting in ectopic site: histological study on sheep.

The aim of this paper was to evaluate through histological analysis of the tissue reaction of deproteinized bovine bone matrix (DBBM) when inserted into the site of intramuscular ectopic sheep. In this study, 16 sheep received 3 groups and these were divided into 2 experimental times: Group 1-sham group, Group 2-particulate autogenous bone and Group 3-DBBM granules. All animals underwent surgical procedures for insertion of materials in an ectopic site (muscles of the lower back and after 3 and 6 months postoperatively, the samples were evaluated by histological analysis. The results indicated that the Sham group showed dense collagen fibers and thin, characterizing fibrosis at 3 and 6 months. In the autograft group there was a significant amount of collagen deposition and decreased inflammation at 6 months postoperatively. Group of DBBM, it was noted the presence of dense connective tissue and surrounding remaining particles was observed the formation of with osteoid characteristic tissue. The DBBM demonstrated biocompatibility, osteoconductivity and small osteogenesis capacity on ectopic site.

Influence of cervical preflaring on apical transportation in curved root canals instrumented by reciprocating file systems.

BACKGROUND: The aim of this study was to evaluate the influence of cervical preflaring on apical transportation in curved root canals prepared using the Reciproc and WaveOne reciprocating file systems. METHODS: Sixty curved canals were instrumented using Reciproc R25 and WaveOne Primary files, with and without preflaring (n = 15). A double-digital technique was used to digitally superimpose the file before instrumentation (#15 K-file) on the final apical reciprocating file (#25/08). The angle between the tip of the initial and final file was measured and recorded. Groups were compared using the Kruskal-Wallis test, and significance was set at p < 0.05. RESULTS: The mean and standard deviation for apical transportation was 0.93 ± 2.48 for the Reciproc Group, 0.84 ± 1.94 for the Preflaring + Reciproc Group, 0.40 ± 1.14 for the WaveOne Group, and 0.83 ± 2.20 for the Preflaring + WaveOne Group. No statistically significant differences were found among the groups (p = 0.9509). CONCLUSIONS: Under the conditions of this study, cervical preflaring did not influence apical transportation in curved root canals instrumented using Reciproc R25 and the WaveOne Primary files. Based on the in vitro measurements of apical transportation, the reciprocating files may be used without preflaring in curved root canals.

Nonprocessed adipose tissue graft in the treatment of peri-implant osseous defects in the rabbit's tibiae: a pilot study.

We hypothesized that a new technique using nonprocessed adipose tissue could regenerate bone around dental implants. Eighteen rabbits received 1 implant per tibia surrounded by a surgically created osseous defect. The defects were assigned for treatment into 3 groups: C, AT, and AB. The percentages of bone-to-implant contact were 17.64% ± 16.22% (AB), 3.54% ± 7.08% (AT), and 12.71% ± 10.11% (C) (ρ = 0.25). The use of adipose tissue around surgically created peri-implant osseous defects interferes with bone formation.

Bioactive glass and connective tissue graft used to treat intrabony periodontal defects.

Different techniques and materials can be used to treat intrabony periodontal defects caused by periodontal diseases. This case report presents an intrabony periodontal defect with bioactive glass and connective tissue graft used as a barrier. Probing depth and clinical attachment gain were reduced at 6 and 12 months post-treatment.

Using chemical vapor deposition diamond finishing burs for conservative esthetic procedures.

The article demonstrates how chemical vapor deposition (CVD) diamond burs were used in a simple esthetic and cosmetic procedure to treat discolored anterior teeth. A patient who experienced discoloration after bleaching was treated with direct resin composite veneers. Excess restorative material close to the periodontium was removed with a CVD diamond bur attached to an ultrasonic handpiece. The results indicate that CVD diamond burs are appropriate for removing excess material at the gingival margins of resin composite restorations without damaging the periodontium.

Nonprocessed adipose tissue graft in the treatment of dehiscence bone defects in rabbit tibiae: a pilot study.

OBJECTIVE: To evaluate the bone repair of surgically created dehiscence-type defects (3 × 5 mm) around dental implants in rabbit tibia using nonprocessed adipose tissue graft or autogenous bone graft. MATERIALS AND METHODS: The bone defects were randomly assigned to 3 groups: blood clot (C), autogenous bone (AB), and nonprocessed adipose tissue (AT). After 3 months, the animals were euthanized. Histomorphometric analyses were performed, and the results were analyzed with analysis of variance and Tukey tests (P ≤ 0.05). Statistics were performed for the percentage of the bone-to-implant contact (BIC) and bone area (BA) within the limits of the threads. RESULTS: The results for BIC in the AT (37.75% ± 28.03%) and C (40.57 ± 13.71%) groups were statistically similar, whereas the AB group had the greatest percentage of BIC (83.37% ± 11.85%). For all groups, the BA percentage was similar (61.48% ± 30.89% in AT; 72.90% ± 14.10% in C; 84.23% ± 11.96% in AB), with no statistically significant differences. CONCLUSION: Nonprocessed adipose tissue is not a comparable substitute for autogenous bone in the treatment of dehiscence bone defects around titanium dental implants.

Microstructural and topographical characterization of different surface treatments of a surgical titanium alloy for dental implants.

OBJECTIVE: To perform a topographical characterization of a titanium alloy subjected to different surface treatments using roughness evaluation, scanning electron microscopy, and atomic force microscopy. MATERIALS AND METHODS: For each group, 6 discs of a titanium alloy had their surfaces modified by 4 treatments. All surfaces were blasted with Al2O3, cleaned, and the specimens were divided into 4 groups: G1, immersion in a standardized acid solution (SAS) (control group); G2, immersion in acetone, followed by immersion in SAS; G3, immersion in acetone, followed by immersion in SAS, followed by immersion in nitric acid; G4, immersion in acetone, followed by immersion in SAS, followed by immersion in sulfuric acid. Roughness parameters were determined with a roughness tester, and data were statistically analyzed using analysis of variance and Tukey tests (α = 5%). RESULTS: Regarding the roughness parameters, no significant differences were found. Scanning electron microscopy and atomic force microscopy showed irregular surfaces with the presence of particles uniformly deposited on the surfaces. CONCLUSION: A similar roughness pattern was created for all the groups. The images and topographic profiles indicated that all the groups showed high levels of roughness.

Single nucleotide polymorphisms in dopamine receptor D2 are associated with bruxism and its circadian phenotypes in children.

Objective: To evaluate the association of bruxism phenotypes with single nucleotide polymorphisms in FKBP5, DRD2, ANKK1, and COMT.Methods: Clinical oral examination was performed to diagnose bruxism phenotypes in 150 children. DNA was collected from saliva. Logistic univariate regression, Chi-square, and Fisher's exact tests were performed (p < 0.05).Results: Bruxism was associated with DRD2 (p = 0.02). Tooth grinding while awake was associated with ANKK1 (p < 0.001), and tooth grinding while asleep was associated with DRD2 in the additive (p = 0.030) and dominant (p = 0.008) model. Tooth clenching while awake was associated with ANKK1 in the additive (p = 0.005) and dominant (p = 0.008) models, whereas tooth clenching while asleep was associated with ANKK1 (p < 0.001) and with COMT in the additive (p = 0.001) and dominant (p = 0.003) models.Discussion: Polymorphisms in DRD2, ANKK1, and COMT are associated with bruxism phenotypes.

Effects of local single dose administration of parathormone on the early stages of osseointegration: A pre-clinical study.

The present study aimed to evaluate the effect of parathormone (PTH) administered directly to the implant's surface prior to insertion, using a large translational animal model. Sixty titanium implants were divided into four groups: (i) Collagen, control group, where implants were coated with Type-I Bovine-collagen, and three experimental groups, where implants received varying doses of PTH: (ii) 12.5, (iii) 25, and (iv) 50 µg, prior to placement. Fifteen female sheep (~2 years old, weighing ~65 kg) received four implants in an interpolated fashion in C3, C4 or C5 vertebral bodies. After 3-, 6- and 12-weeks, samples were harvested, histologically processed, qualitatively and quantitatively assessed for bone-to-implant contact (BIC) and bone area fraction occupancy (BAFO). BIC yielded lower values at 6-weeks for 50 µg relative to the control group, with no significant differences, when compared to the 12.5- and 25-µg. No significant differences were detected at 6-weeks between collagen, 12.5- and 25-µg groups. At 3- and 12-weeks, no differences were detected for BIC among PTH groups. With respect to BAFO, no significant differences were observed between the control and experimental groups independent of PTH concentration and time in vivo. Qualitative observations at 3-weeks indicated the presence of a more mature bone near the implant's surface with the application of PTH, however, no significant differences in new bone formation or healing patterns were observed at 6- and 12-weeks. Single local application of different concentrations of PTH on titanium implant's surface did not influence the osseointegration at any time-point evaluation in low-density bone.

In vitro evaluation of the removal force of abutments in frictional dental implants.

The objective of the present work was to determine some force parameters for removal of an abutment from a dental implant in a frictional system (locking taper, 1.23 degrees). Ten implants of the same length (11 mm) and different diameters were selected, along with 10 straight abutments (13 mm length) with different diameters. Abutments were attached to implants without application of force. Fixation of the implant-abutment mount (IA) (repeated 1-5 times) was performed through the impact of a body weight (compression force, tapping) left from a known height. After each group of tappings, IA mounts were coupled with a tensile strength tester. The lowest removal value was found after the first tapping of mount #2 (83 N, implant diameter 3.3 mm/4.5 mm abutment diameter), and the highest removal value happened with mount #8 after the fifth tapping (420 N, 5.0 mm/5.5 mm). The force to remove IA mounts increased with the number of tappings and with the increase in abutment mass. Three activations (tappings) of the abutment were considered necessary to yield optimal stability, demonstrated by the large increase in removal force.

Osteoconductivity of Biphasic Calcium Phosphate Ceramic Improves New Bone Formation: A Histologic, Histomorphometric, Gene Expression, and Microcomputed Tomography Study.

PURPOSE: The purpose of this study was to evaluate bone repair with two bone substitutes, deproteinized bovine bone and biphasic calcium phosphate ceramics, associated with autogenous bone. MATERIALS AND METHODS: The experimental groups were as follows: autogenous bone only (AB), autogenous bone/deproteinized bovine bone (1:1), and autogenous bone/biphasic calcium phosphate ceramic (1:1). After 30, 60, and 90 days, animals were euthanized and samples were collected for microcomputed tomography (micro-CT), histologic, histomorphometric, and expression analyses of VEGFA, RUNX2, ALP, COL1A1, OCN, PHEX, RANKL, and OPG genes by real-time polymerase chain reaction (PCR) array. RESULTS: Histomorphometric analysis showed no difference in the amount of immature bone between AB and AB/biphasic calcium phosphate ceramic at 30 and 60 days. There was less mature bone formation in the AB/deproteinized bovine bone at 60 days compared with AB/biphasic calcium phosphate ceramic and AB, and a lower amount of immature bone in the AB/deproteinized bovine bone at 30 and 60 days compared with the AB (P ≤ .05). Micro-CT analysis showed higher immature bone volume (BVI) in the AB/biphasic calcium phosphate ceramic at 60 days and lower BVI at 90 days (P ≤ .05). Molecular analysis showed a lower expression of all genes in the AB/deproteinized bovine bone and AB/biphasic calcium phosphate ceramic compared with AB at all time points. A greater expression of RANKL was found in the AB/deproteinized bovine bone compared with AB/biphasic calcium phosphate ceramic at 30 days (P ≤ .05), and a lower expression of the OC, RUNX2, and ALP genes in AB/deproteinized bovine bone and AB/biphasic calcium phosphate ceramic was found compared with AB at all time points (P ≤ .05). CONCLUSION: The use of biphasic calcium phosphate ceramic resulted in greater immature bone formation than deproteinized bovine bone at an early assessment. The studied bone regeneration genes were downregulated in comparison to the control.

The Role of Marine Organic Extract in Bone Regeneration: A Pilot Study.

Novel biomaterials capable of accelerating the healing process of skeletal tissues are urgently needed in dentistry. The present in vivo study assessed the osteoconductive and osteoinductive properties of experimental biphasic bioceramics (HA-TCP) modified or not by a nacre extract (marine organic extract, MOE) in a sheep model. Fabrication of MOE involved mixing ground nacre (0.05 g, particle sizes < 0.1 mm) with glacial ethanoic acid (5 mL, pH 7) for 72 hours using external magnetic stirring (25°C). Nonreactive carriers (sterile polythene tubes; 3/animal, radius: 2.5 mm, length: 10.0 mm) pertaining to the control (empty) or experimental groups (HA-TCP or MOE-modified HA-TCP) were implanted intramuscularly into the abdominal segment of the torso in sheep (n = 8, age: 2 years, weight: 45 kg). Euthanization of animals was performed at 3 and 6 months after surgery. Tissues harvested were subjected to macroscopic and radiographic assessments. Specimens were then stained for histological analysis. Both control and experimental animals were capable of inducing the neoformation of fibrous connective tissue at both time points where superior amounts of tissue formation and mineralization were detected for experimental groups (unaltered (at 3 and 6 mos) and MOE-modified HA-TCP (at 3 mos)). Histological results, however, revealed that mature bone formation was only observed for specimens fabricated with MOE-modified HA-TCP in a time-dependent manner. The present study has successfully demonstrated the in vivo utility of experimental biphasic bioceramics modified by MOE in an ectopic grafting sheep model. Promising osteoconductive and osteoinductive properties must be further developed and confirmed by subsequent research.

Chlorhexidine diminishes the loss of bond strength over time under simulated pulpal pressure and thermo-mechanical stressing.

OBJECTIVES: The purpose of this study was to investigate the effects of chlorhexidine (CHX) digluconate at 0.2% and 2% on dentin bonding durability of etch-and-rinse and self-etch adhesive systems. METHODS: In this study were used 24 extracted non-carious human third-molars. The occlusal surfaces of the molar crowns were removed with a low-speed diamond saw to expose flat dentin surfaces. The tested materials were Single-Bond (SB) (two-step etch-and-rinse adhesive) and Clearfil Tri S Bond (CTSB) (all-in-one self-etch adhesive) used in association or not with CHX at 0.2% and 2%. The bonding systems were applied according to manufacturer's instructions and followed by composite application (Z250). For each condition, half of the specimens was immediately submitted to microtensile test and half of them was submitted to long-term storage of 6 months under simulated pulpal pressure and thermo-mechanical stressing before testing. The data were analyzed using Two-Way ANOVA and Tukey post hoc test (alpha=0.05). Failure patterns of the specimens were observed using scanning electron microscopy. RESULTS: The falling % in bond strength over the 6-month period was: SB control-43.64%; SB/0.2%CHX-23.79%; SB/2%CHX-26.42%; CTSB control-40.94%; CTSB/0.2%CHX-37.07%; CTSB/2%CHX-22.14%. The fracture modes were predominantly adhesive, mainly in the specimens of terminal groups. CONCLUSIONS: CXH digluconate at 2% was able to diminish loss of microtensile bond strength over time associated to both etch-and-rinse and self-etch adhesives. Lower concentration of CHX (0.2%) was not able to diminish the loss of bond strength over time when associated to the self-etch adhesive CTSB.

Oral and masticatory rehabilitation using osseointegrated dental implants after resective treatment of multicystic ameloblastoma in the lower jaw with a fibula graft.

Ameloblastoma is an aggressive odontogenic tumor which typically occurs between third and fourth decade of life that often needs resective approach. Immediate reconstruction may show better results. The treatment of multicystic ameloblastoma in the mandible being a rare case that occurred in the late second decade of life, which was surgically removed along with the affected teeth with safety margins, and the region was immediately reconstructed using a vascularized graft, removed from the fibula. Its integration, in combination with osseointegrated dental implants and fixed implant-supported prostheses, restored chewing function and esthetics. After 6 years from fibular graft and 24 months of dental implants, an excellent outcome was observed, with oral health and normal functions properly restored, and the immediate reconstruction of the mandible in resective cases, associated with oral rehabilitation with dental implants, may be considered a suitable treatment option.

Horizontal alveolar ridge expansion followed by immediate placement of implants and rehabilitation with zirconia prosthesis.

In recent years, there have been a growing number of procedures involving dental implants. Most cases, though, are characterized by bone atrophy, especially horizontal atrophy. This clinical case aims to report a technique for the expansion of the horizontal alveolar ridge. A longitudinal fracture was created in the alveolar ridge to expand the bone, followed by immediate insertion of dental implants along with a particulate allogeneic bone graft. Eight implants were placed in the maxilla, and after 12 months, a surgical reopening was performed, along with rehabilitation with a protocol-type prosthesis, for which a zirconia infrastructure was made. The patient was observed during a 10-month follow-up period in which an effective osseointegration of all implants was achieved as a result of such a technique. The split-crest technique followed by the immediate placement of implants and a particulate allogeneic bone graft proved to be effective, with a predictable osseointegration.

Microbial evaluation of implant surface - a clinical study comparing submerged, non-submerged and immediately loaded implants

Aim: The aim of the present study was to evaluate the microbial contamination in internal and external walls of cone morse implant walls. Methods: Eleven patients with edentulous mandibular posterior area were selected to received dental implants, divided into groups: submerged (S), non-submerged (NS), and immediately loaded (IL). Microbiological evaluations (microorganisms' number, aerobic and anaerobic colony forming units (CFU) number and microorganisms' qualification) were divided into internal and external collection of the implant walls, at different stages: T0 (surgical procedure), T2 (suture removal), T4 (reopening S group), T6 (suture removal S group), and T8 (abutment placement in S and NS). All data were submitted to statistical analyses, with confidence level of 0.05. Results: There was difference in number of microorganisms observed over time within the same group (p < 0.05). A difference was observed in CFU when evaluated within the same group over time (p < 0.05), except for the IL group. In internal collection, a predominance of non-formation of microorganisms was observed at T0 in all groups, while formation of Gram-positive Diplococci and Gram-positive Bacilli was observed at T8 (p>0.05). In external collection, an increase in number of microorganisms was observed at T0. Conclusion: There was no difference in microbial contamination among the evaluated groups. The microorganism's colonization changed over time