Influence of Smoking on Dental Implant Osseointegration: A Radiofrequency Analysis of 194 Implants.

Although many studies have related smoking to peri-implantitis and marginal bone loss, little is known of its potential impact on dental implant osseointegration. The present clinical study explores the influence of smoking on secondary stabilization based in radiofrequency analysis. A total of 194 implants in 114 patients were included. Implant stability was evaluated on the day of surgery and at a minimum of 90 days after implantation, when osseointegration is considered to have been completed. The evolution of implant stability was compared between 2 groups: smokers and nonsmokers. The following variables were also analyzed: implant brand and model, length, diameter, insertion torque, bone density according to the Misch classification, location of the implant, and patient age and gender. The results showed that smoking did not affect the primary stability of the implant, although it was associated with a marked decrease in secondary stability. The nonsmokers showed a gain of 2.69 points (95% confidence interval [CI]: 1.529-3.865; P < .001) in the osseointegration process. However, in the smokers group, implant stability was seen to decrease 0.91 points (95% CI: -3.424 to 1.600; P < .004), generating a difference of 3.61 points between smokers and nonsmokers. Smoking is thus concluded to be an important factor that must be taken into account when seeking good implant osseointegration outcomes.

In Vitro Study on the Influence of the Buccal Surface Convexity of the Tooth upon Enamel Loss after Bracket Removal.

Polishing after the removal of brackets is the final step in orthodontic treatment. It is simple to perform, though some studies have reported that polishing causes damage to the enamel surface. An in vitro study was made of the influence of the buccal surface convexity of the tooth upon possible enamel loss when the remaining resin and adhesive are removed after bracket decementing using two different polishing modes: a tungsten carbide bur at low and high speeds. The convexity of the buccal surface was quantified in 30 incisors and 30 premolars. A stereoscopic microscope was used to obtain photographs of the profile of the crown, and Image J software was used to calculate convexity by dividing the length of a line from the cementoenamel junction to the incisal margin by another line from the mentioned junction to the maximum convexity of the buccal surface. Brackets were cemented on all the teeth and were decemented 24 h later. In both groups, the residual composite was removed with a tungsten carbide bur at a low speed in one-half of the teeth and at a high speed in the other half. The buccal surface of each tooth was then photographed again, and the convexity was calculated and compared against the baseline value. The difference between the two values were taken to represent the enamel loss. The convexity of the premolars was significantly greater than that of the incisors, but this did not result in greater enamel loss when the same polishing mode was used. However, the tungsten carbide bur at a high speed proved more aggressive, causing significantly greater enamel loss than when used at a low speed.

Comparison of the push-out bond strength of two hydraulic calcium silicate-based endodontic sealers and an epoxy resin-based sealer.

Background: The aim of this study was to assess and compare the push-out bond strength of AH Plus Bioceramic Sealer, TotalFill BC Sealer HiFlow and epoxy resin sealer AH Plus in root canals. Material and Methods: Ninety single rooted teeth with were prepared using rotatory files, 5,25 % sodium hypochlorite and 17% ethylenediaminetetraacetic acid. The teeth were divided into three groups (n=30) and obturated using the single-cone technique with TotalFill BC Sealer HiFlow in Group 1, AH Plus Bioceramic Sealer in Group 2, and AH Plus in Group 3. Three sections (coronal, middle and apical) were obtained for each root (n=270), and the push-out bond strength was evaluated for each section using an universal testing machine. The push-out bond strength among the groups was analysed using the Welch test, while the Mann-Whitney test was used to compare resistance among the coronal, middle and apical thirds of the root. Results: Significant differences were observed between the mean push-out bond strength of the two hydraulic calcium silicate sealers and the resin-based root canal sealer (P> 0.05). Only Group 1 exhibited significant regional differences among the root thirds, with the apical third demonstrating significantly higher strength values compared to the middle and coronal thirds. Conclusions: Based on the present study, it can be concluded that there are differences in the push-out bond strengths between the two hydraulic calcium silicate sealers (HCSSs) and the resin-based sealer, while no significant difference was found between the two HCSSs. Key words:Push-out bond strength, root canal sealer, root canal obturation, hydraulic calcium silicate cements, bioceramic sealers.

A Biomechanical Analysis of the Influence of the Morfology of the Bone Blocks Grafts on the Transfer of Tension or Load to the Soft Tissue by Means of the Finite Elements Method.

Edentulism produces resorption of alveolar bone processes, which can complicate placement of dental implants. Guided bone regeneration techniques aim to recover the volume of bone. These treatments are susceptible to the surgical technique employed, the design of the autologous block or the tension of the suture. These factors can relate to major complications as the lack of primary closure and dehiscence. The present study, using finite element analysis, aimed to determine differences in terms of displacement of the oral mucosa, transferred stress according to Von Mises and deformation of soft tissue when two block graft designs (right-angled and rounded) and two levels of suture tension (0.05 and 0.2 N) were combined. The results showed that all the variables analyzed were greater with 0.2 N. Regarding the design of the block, no difference was found in the transferred stress and deformation of the soft tissue. However, displacement was related to a tendency to dehiscence (25% greater in the right-angled/chamfer design). In conclusion different biomechanical behavior was observed in the block graft depending on the design and suture tension, so it is recommended to use low suture tension and rounded design. A novel finite element analysis model is presented for future investigations.

Intratubular penetration ability in the canal perimeter using HiFlow bioceramic sealer with warm obturation techniques and single cone.

Background: The aim of this paper was to evaluate the intratubular penetration percentage in the perimeter of the canals of the calcium silicate-based sealer HiFlow, using three warm obturation techniques, continuous wave (CW) and vertical condensation (VC) with two different types of gutta-percha (conventional (NG) and bioceramic-coated (BG), GuttaCore (GC) and single cone (SC) with BG in different root thirds. Material and Methods: 180 human teeth with a single root were selected including incisors, canines and premolars were prepared and randomly divided into six groups (n=30). Teeth were filled using a bioceramic sealer TotalFill BC Sealer HiFlow (HiFlow) and two different types of gutta-percha, with CW, VC and GC techniques, the teeth in the control group were filled with SC technique and BG gutta-percha. The teeth were sectioned and evaluated as one-third portions in each case under a confocal laser microscope. The penetration ability in the canal's perimeter was carried out with the Autocad® programme. Data was analyzed using Levene's test (p<0,05), ANOVA test (p<0,05), Welch's comparison test (p<0,05), Games-Howell multiple comparison test (p<0,05), Bonferroni test (p<0,05). Results: The percentages relative to penetration was higher in the warm obturation techniques than the SC in all thirds evaluated. Games-Howell test (p<0,05) showed up significant differences in multiple comparisons. There was greater penetration in the perimeter of the canals in the coronal third than in the apical third in all of the techniques. Conclusions: The warm obturation techniques (CW, VC and GC) generated a greater intratubular penetration percentage in the canal perimeter of the sealer than the single cone in all thirds. Key words:HiFlow, calcium silicate-based sealer, confocal laser microscope, dentinal tubules.

Intratubular penetration capacity of HiFlow bioceramic sealer used with warm obturation techniques and single cone: A confocal laser scanning microscopic study.

Objective: The aim of this paper was to evaluate the intratubular penetration area of a bioceramic sealer, using continuous wave (CW), vertical condensation (VC) with two different types of gutta-percha (conventional (NG) and bioceramic-coated (BG)) and single cone (SC) technique with BG gutta-percha, in different root thirds. Methods: A total of 150 mature single-root human teeth (including incisors, canines and premolars) were prepared and randomly divided into five groups (n = 30). Teeth were filled using a bioceramic sealer (TotalFill BC Sealer HiFlow ®) and two different types of gutta-percha, with CW and VC techniques, the teeth in the control group were filled with SC technique and BG gutta-percha. The teeth were sectioned and evaluated as one-third portions in each case under a confocal laser microscope. The penetration area measurements were carried out with the Autocad ® programme. Data was analyzed using the one-factor ANOVA test (p < 0.05) and Post Hoc Test (p < 0.05). Results: The ANOVA Test showed significant differences in the penetration areas of the five obturation techniques (P < 0.05). The Post Hoc Test exhibited significant differences in multiple comparisons (P < 0.05). There was more dentinal tubule penetration in the coronal third than in the apical third in all techniques. Conclusions: The intratubular penetration of the bioceramic sealer was influenced by the obturation techniques tested, but not by the different gutta-percha tested. There was more penetration of sealer in the warm obturation techniques than the SC, regardless of the type of gutta-percha used.

Assessment of Oxygen Expansion during Internal Bleaching with Enamel and Dentin: A Comparative In Vitro Study.

Internal bleaching is a conservative, non-invasive, and simple treatment that is frequently performed in daily clinical practice. The present in vitro study analyzes the oxygen expansion of different bleaching agents resulting from the oxidation reaction when interacting with enamel and dentin. Enamel and dentin were crushed separately until obtaining a fine powder with particles of an approximate size between 0.06 and 0.2 mm. Each enamel and dentin sample were mixed with 37% carbamide peroxide (CP 37%), 30% hydrogen peroxide (HP 30%), sodium perborate (SP) combined with HP 30% (HP 30% + SP) and SP with distilled water (SP). A total of 280 1 mm diameter glass tubes were used with 70 for each bleaching agent (30 for powdered enamel evaluation, 30 for powdered dentin evaluation, and 10 controls). The bleaching agents were placed in the prepared tubes immediately after mixing the components. As expansion occurred, the oil inside the tube was displaced, through which the resulting expansion was evaluated and measured for 10 days. A significant expansion was observed that varied in magnitude according to the bleaching agent and the tooth structure used. Student's t test and Welch's ANOVA were used to analyze the data obtained. The highest mean expansion of both enamel and dentin was observed with 30% HP (66.6 mm for enamel, 94.5 mm for dentin) followed by HP 30% + SP (48.6 mm for enamel, 52.7 mm for dentin), CP 37% (38.4 mm for enamel, 52.6 mm for dentin) and finally SP with water (12.7 mm for enamel, 4.4 mm for dentin). It was observed that the expansion in the SP group with enamel was significantly lower than in the rest of the groups, while that registered for HP 30% was significantly higher. (p < 0.001). The results with dentin were similar, with a significantly lower expansion for SP and higher for HP 30% (p < 0.001). The oxygen expansion observed as a result of the interaction between bleaching agents and dental tissues could contribute to improving our understanding of bleaching and its results. These results suggest that bleaching agents react with the organic component of the tooth structure.

Cellular Responses in Human Dental Pulp Stem Cells Treated with Three Endodontic Materials.

Human dental pulp stem cells (HDPSCs) are of special relevance in future regenerative dental therapies. Characterizing cytotoxicity and genotoxicity produced by endodontic materials is required to evaluate the potential for regeneration of injured tissues in future strategies combining regenerative and root canal therapies. This study explores the cytotoxicity and genotoxicity mediated by oxidative stress of three endodontic materials that are widely used on HDPSCs: a mineral trioxide aggregate (MTA-Angelus white), an epoxy resin sealant (AH-Plus cement), and an MTA-based cement sealer (MTA-Fillapex). Cell viability and cell death rate were assessed by flow cytometry. Oxidative stress was measured by OxyBlot. Levels of antioxidant enzymes were evaluated by Western blot. Genotoxicity was studied by quantifying the expression levels of DNA damage sensors such as ATM and RAD53 genes and DNA damage repair sensors such as RAD51 and PARP-1. Results indicate that AH-Plus increased apoptosis, oxidative stress, and genotoxicity markers in HDPSCs. MTA-Fillapex was the most cytotoxic oxidative stress inductor and genotoxic material for HDPSCs at longer times in preincubated cell culture medium, and MTA-Angelus was less cytotoxic and genotoxic than AH-Plus and MTA-Fillapex at all times assayed.

Comparative study of the radiopacity of resin cements used in aesthetic dentistry.

PURPOSE: The aim of this study was to compare the radiopacity of 6 modern resin cements with that of human enamel and dentine using the Digora digital radiography system, to verify whether they meet the requirements of ANSI/ADA specification no. 27/1993 and the ISO 4049/2000 standard and assess whether their radiopacity is influenced by the thickness of the cement employed. MATERIALS AND METHODS: Three 3-thickness samples (0.5, 1 and 1.5 mm) were fabricated for each material. The individual cement samples were radiographed on the CCD sensor next to the aluminium wedge and the tooth samples. Five radiographs were made of each sample and therefore five readings of radiographic density were taken for each thickness of the materials. The radiopacity was measured in pixels using Digora 2.6 software. The calibration curve obtained from the mean values of each step of the wedge made it possible to obtain the equivalent in mm of aluminium for each mm of the luting material. RESULTS: With the exception of Variolink Veneer Medium Value 0, all the cements studied were more radiopaque than enamel and dentin (P<.05) and complied with the ISO and ANSI/ADA requirements (P<.001). The radiopacity of all the cements examined depended on their thickness: the thicker the material, the greater its radiopacity. CONCLUSION: All materials except Variolink Veneer Medium Value 0 yielded radiopacity values that complied with the recommendations of the ISO and ANSI/ADA. Variolink Veneer Medium Value 0 showed less radiopacity than enamel and dentin.