Expectancy from, and acceptance of augmented reality in dental education programs: A structural equation model.

OBJECTIVE: Dental schools need hands-on training and feedback. Augmented reality (AR) and virtual reality (VR) technologies enable remote work and training. Education programs only partially integrated these technologies. For better technology integration, infrastructure readiness, prior-knowledge readiness, expectations, and learner attitudes toward AR and VR technologies must be understood together. Thus, this study creates a structural equation model to understand how these factors affect dental students' technology use. METHODS: A correlational survey was done. Four questionnaires were sent to 755 dental students from three schools. These participants were convenience-sampled. Surveys were developed using validity tests like explanatory and confirmatory factor analyses, Cronbach's ɑ, and composite reliability. Ten primary research hypotheses are tested with path analysis. RESULTS: A total of 81.22% responded to the survey (755 out of 930). Positive AR attitude, expectancy, and acceptance were endogenous variables. Positive attitudes toward AR were significantly influenced by two exogenous variables: infrastructure readiness (B = 0.359, ß = 0.386, L = 0.305, U = 0.457, p = 0.002) and prior-knowledge readiness (B = -0.056, ß = 0.306, L = 0.305, U = 0.457, p = 0.002). Expectancy from AR was affected by infrastructure, prior knowledge, and positive and negative AR attitudes. Infrastructure, prior-knowledge readiness, and positive attitude toward AR had positive effects on expectancy from AR (B = 0.201, ß = 0.204, L = 0.140, U = 0.267, p = 0.002). Negative attitude had a negative impact (B = -0.056, ß = -0.054, L = 0.091, U = 0.182, p = 0.002). Another exogenous variable was AR acceptance, which was affected by infrastructure, prior-knowledge preparation, positive attitudes, and expectancy. Significant differences were found in infrastructure, prior-knowledge readiness, positive attitude toward AR, and expectancy from AR (B = 0.041, ß = 0.046, L = 0.026, U = 0.086, p = 0.054). CONCLUSION: Infrastructure and prior-knowledge readiness for AR significantly affect positive AR attitudes. Together, these three criteria boost AR's potential. Infrastructure readiness, prior-knowledge readiness, positive attitudes toward AR, and AR expectations all increase AR adoption. The study provides insights that can help instructional system designers, developers, dental education institutions, and program developers better integrate these technologies into dental education programs. Integration can improve dental students' hands-on experience and program performance by providing training options anywhere and anytime.

The Antibacterial and Antifungal Activity of Chlorhexidine Diacetate Incorporated into Acrylic Resins Used in Provisional Restorations.

Objective: The surface of provisional restorations applied before conventional or implant- supported fixed restorations may cause bacterial or fungal biofilm formation. The aim of this study was to evaluate the antimicrobial activity of acrylic resins used in provisional restorations modified with chlorhexidine diacetate. Methods: 120 cylindrical, auto-polymerized resin samples modified with chlorhexidine diacetate were prepared at concentrations of 0 (control), 1, 3, 5 wt %. The antimicrobial activity was examined against Streptococcus mutans, Enterococcus faecalis, and Candida albicans using Crystal Violet quantification, MTT assay, and Scanning Electron Microscopy. Data were analyzed by ANOVA and paired sample t-tests (α=0.05). Results: The addition of chlorhexidine diacetate influenced the growth rate and metabolic activity of microorganisms. The antimicrobial effect against C. albicans and S. mutans statistically increased with the percentage of chlorhexidine diacetate. E. faecalis bacteria were less affected by chlorhexidine diacetate compared to other pathogens. Conclusion: It has been shown that the effectiveness of CHDA in inhibiting the proliferation of microorganisms correlated positively with increasing concentration levels. More research is needed to confirm the impact of different chlorhexidine concentrations on the mechanical properties, clinical efficacy, and antimicrobial properties of CDHA.

Evaluation of bite force, quality of life, and patients' satisfaction in elderly edentulous patients using implant overdentures.

Purpose: This study aimed to compare the bite force (BF) between complete dentures and implant overdentures (IODs) retained by two mandibular implants. Additionally, we evaluated the quality of life (QoL) and patient satisfaction among individuals using IODs. In addition, the effects of demographic parameters such as age and sex, and clinical parameters such as implant length, implant diameter, attachment height, attachment color, and interimplant distance on BF, QoL, and patient satisfaction were evaluated. Materials and methods: A total of 51 edentulous patients rehabilitated with the maxillary complete dentures and mandibular IODs retained by two implants were included in this study. BF was measured using a force meter pre- and post-implant in the same patients. Oral health-related quality of life (OHRQoL) was assessed with the Oral Health Impact Profile (OHIP-14) and patient satisfaction was assessed with the Visual Analog Scale (VAS) questionnaires. Results: It was found that BF values were statistically higher for IODs than complete dentures (P < .001). In terms of attachment height of the OHIP scores, there was a significant difference in the psychological disability and social disability domains (P < .05). When examining the change in patient satisfaction as a function of sex, it was found that mandibular retention satisfaction differed significantly by sex (P < .05), but there was no significant difference in the other domains. Conclusion: Within the limitations of this study, it was observed that the BF increased after the use of IODs. Several factors, including age, interimplant distance, attachment height, and attachment color, were found to impact OHRQoL. Sex and implant diameter were identified as factors affecting patient satisfaction.

Comparison of Periodontal Health and Marginal Bone Loss in Mandibular First Molar Single-Crown Dental Implants Placed in Different Positions.

The aim of the present study is to compare the periodontal health and marginal bone loss (MBL) between single-crown dental implants placed interdentally and mesial to the edentulous space. Patients treated with single-crown dental implants between 01/04/2014 and 01/04/2021 were included in the study. The included patients were divided into 2 groups. Group 1 consisted of single implant crowns inserted interdentally with a distal neighboring mandibular second molar and Group 2 consisted of single molar implant crowns inserted distally to the second premolar tooth without a neighboring second molar. The measurements for probing pocket depth, gingival index, and plaque index were made in both groups at the 60-month control session to evaluate periodontal health of the single-crown dental implants. The marginal bone levels of distal and mesial aspects of all implants were measured at the 60-month control session on panoramic radiographs. Forty-six and sixty-one patients were included in Groups 1 and 2, respectively. There was a significantly higher distal MBL in Group 2 compared with Group 1 (P < 0.05). Mesial MBL was higher in Group 1, however, this difference was not significant. The periodontal parameters of probing pocket depth, gingival index, and PI were all significantly higher in Group 1 compared with Group 2 at the 60-month control evaluation (P < 0.05). Single-crown dental implants placed interdentally may show decreased distal MBL and periodontal health compared with single-crown dental implants placed mesial to the edentulous space.

Anti-adherent activity of nano-coatings deposited by thermionic vacuum arc plasma on C. albicans biofilm formation.

BACKGROUND: The purpose of this study was to analyze the anti-adherent activity of nano-coatings deposited by Thermionic Vacuum Arc plasma on C. albicans ATCC 10231 biofilm. MATERIALS AND METHODS: A total of 80 disc-shaped (2 × 10 mm) polymethymethacrylate samples were prepared and divided into four groups with 10 samples in each group (Control, ZnO, SnO2, Ag) (n = 10). Using thermionic vacuum arc plasma, they were coated with ZnO, SnO2, and Ag. 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and Crystal Viole (CV) assays were conducted for biofilm quantification. Scanning electron microscopy (SEM) was used to observe biofilm images of C. albicans biofilm. RESULTS: MTT and CV mean values differ statistically significantly between all groups (p ⩽ 0.05). The SnO2 group had the lowest mean value, whereas the control group received the highest value. CONCLUSION: SnO2 coating shown greater anti-adherent activity than either metal oxides. C. albicans biofilm formation on denture base surfaces is reduced following Thermionic Vacuum Arc plasma coating with SnO2.

Could Helium Plasma Treatment be a Novel Approach to Prevent the Biofilm Formation of Candida albicans?

There is no definitive method to prevent Candida albicans (C. albicans) biofilm formation on polymethyl methacrylate (PMMA) surfaces. The objective of this study was to evaluate the effect of Helium plasma treatment (before the application of removable dentures to the patient) to prevent or reduce C. albicans ATCC 10,231 the anti-adherent activity, viability, and biofilm formation on PMMA surfaces. One hundred disc-shaped PMMA samples (2 mm × 10 mm) were prepared. The samples were randomly divided into 5 surface groups and treated with different concentrations of Helium plasma: G I: Control group (untreated), G II: 80% Helium plasma-treated group, G III: 85% Helium plasma-treated group, G IV: 90% Helium plasma-treated group, G V: 100% Helium plasma-treated group. C. albicans viability and biofilm formations were evaluated using 2 methods: MTT (3-(4,5-dimethyl thiazolyl-2)-2, 5-diphenyltetrazolium bromide) assays and Crystal Violet (CV) staining. The surface morphology and C. albicans biofilm images were observed with scanning electron microscopy. The Helium plasma-treated PMMA groups (G II, G III, G IV, G V) observed a significant reduction in C. albicans cell viability and biofilm formation compared with the control group. Treating PMMA surfaces with different concentrations of Helium plasma prevents C. albicans viability and biofilm formation. This study suggests that Helium plasma treatment might be an effective strategy in modifying PMMA surfaces to prevent denture stomatitis formation.

The effects of metal nanoparticles incorporation on the mechanical properties of denture base acrylic resin.

Purpose: The aim of this study was to examine the flexural strength of acrylic resin base material incorporated with iron, copper, and titanium nanoparticles. Materials and methods: Seventy bars of samples (65x10x2.5 mm3) were divided into seven groups. Acrylic samples were prepared according to the manufacturer's instructions. Fe2O3, CuO and TiO2 nanoparticles were manually added in a proportion of 1wt% and 3wt% to the heat-polymerized acrylic resin. The Universal Testing Machine was used for 3-point flexural test of 5 mm/min force. ANOVA and Weibull analyses were used for the statistical analyses. Results: A statistical difference was found between the nanoparticle-added group and the control group. The highest mean value was observed for the 1wt% TiO2 added group, (84.99 MPa) and the lowest value was for the 3wt% CuO added group (71.32 MPa) (p<0,001). The 3wt% Fe2O3 and CuO added groups showed lower values than the control group. Conclusion: The incorporation of TiO2 nanoparticles into acrylic resin in a proportion of 1wt% increased the flexural strength values of the resins. Within the limitations, the nanoparticle addition to acrylic resins could improve the mechanical properties; however, when the percentage of nanoparticle addition increases, the flexural strength values of the acrylic resins decrease.

Influence of atmospheric pressure changes on dentin bond strength of conventional, bulk-fill and single-shade resin composites.

INTRODUCTION: The purpose of this study was to investigate the dentin bond strength of composite resins in response to environmental pressure changes. METHODS: Ninety extracted human molar teeth were used. A mould (3 mm x 4 mm) was adapted on dentin, resin composites (conventional [n = 30] and single-shade composites [Ohmnicroma] [n = 30]) were filled in two increments of 2 mm. The bulk-fill composites (n = 30) were filled with one 4 mm increment. The specimens were stored for 30 days in artificial saliva. The specimens were exposed to hyperbaric pressure (283.6 kPa; 2.8 atmospheres absolute [atm abs]) or hypobaric pressure (34.4 kPa; 0.34 atm abs) once daily for 30 days and the control group was stored at atmospheric pressure for 30 days. The bond strength was tested with a universal testing machine and the failures were examined with a stereomicroscope and scanning electron microscope. Statistical analyses were performed using analysis of variance with post hoc tests, and the Weibull analysis. RESULTS: Regardless of environmental pressure changes, the bulk-fill composites showed the highest bond strength. There was no significant difference in bond strength between the hypobaric and atmospheric pressure (control) groups after 30 days in all resins. The hyperbaric group showed lower bond strength for bulk-fill composites than the control group. CONCLUSIONS: Dentists experienced in diving and aviation medicine should definitely take part in the initial and periodic medical examinations of divers and aircrew to give appropriate treatment. Bulk-fill composite resins can be preferred in divers and aircrew due to high bond strength values.

Effect of Potassium Aluminum Sulfate Application on the Viability of Fibroblasts on a CAD-CAM Feldspathic Ceramic before and after Thermocycling.

Potassium aluminum sulfate (alum) is a known adjuvant, which has been used as a mordant in textile industry for color fixation. This material has potential to be incorporated into dentistry for color stability, yet its toxicity first needs to be evaluated. The present study aimed to evaluate the cytotoxic potential of potassium aluminum sulfate (alum) on fibroblasts when applied onto feldspathic ceramic before and after thermocycling. Forty-eight feldspathic ceramic specimens were divided into four groups (FC: no alum application or thermocycling; FCT: thermocycling without alum application; FA: alum application without thermocycling; FAT: alum application and thermocycling) (n = 12). Cell viability was assessed by using a tetrazolium salt 3-[4,5-dimethylthiazol-2-yl]-2,5-diphnyltetrazolium bromide assay at 24 and 72 h, and cell cultures without any ceramic specimens served as control (C). One sample from each material group was further analyzed with energy dispersive X-ray spectroscopy (EDX). Cell viability at different time intervals within each group was analyzed with Friedman tests, while Kruskal−Wallis tests were used to compare the test groups within each time interval. Pairwise comparisons were further resolved by using Wilcoxon tests (a = 0.05). C had lower (p = 0.01) and FA had higher (p = 0.019) cell viability after 72 h. After 24 h, the highest cell viability was observed in C (p ≤ 0.036). After 72 h, the differences between C and FA, C and FAT, FC and FA, and FCT and FAT were nonsignificant (p > 0.05). Cell viability was not affected by alum application or thermocycling at any time interval (p ≥ 0.631). EDX analysis showed an increase in potassium concentration in FA and FAT when compared with FC and FCT. Regardless of the time interval, alum application onto feldspathic ceramic and thermocycling did not influence the cell viability.

Maintenance requirements and marginal bone loss associated with implant-retained overdentures: a retrospective cohort study.

OBJECTIVES: To evaluate the maintenance requirements and the presence of prosthetic complications associated with marginal bone loss in the implant-retained bar and locator prostheses. MATERIALS AND METHODS: The study was executed between the years 2013 and 2018 on 114 patients who had undergone 283 dental implants. Patients were examined at follow-up recall sessions at 12 and 24 months after the placement of the dentures. The clinical examination also included intraoral and extraoral examinations of the patients; compatibility of the prostheses placed to about occlusion; an adaptation of the prosthesis to the tissues, health, and continuity of the soft tissues; complaints of the patients; implant success rates; and marginal bone loss, and prosthetic complications were evaluated at follow-up sessions, and statistical analysis was performed. RESULTS: Locator attachment was placed in 94 patients with separated mandibles and maxillae, and a removable prosthesis with a bar attachment was placed in 20 patients. When evaluating the level of marginal bone loss regardless of the presence of complications, the area where the implant was set, the number of days after loading, and the type of retainer, it was found to be significant at the end of the 12th the 24th months. The results showed a significant relationship between the prosthesis type and the presence of complications at month 24 (p < 0.05). There was no significant relationship between the position of the denture and the presence of complications at month 12 (p > 0.05). There was no significant relationship between the location of the denture and the presence of complications at month 24 (p > 0.05). CONCLUSION: Complications do not affect marginal bone loss, but the resulting marginal bone loss is the result of the patient not paying enough attention to oral hygiene. Routine inspections of the prosthesis after the completion of treatment seem to be important. If the requirements resulting from these checks are met, complications that may occur in the future will be prevented. CLINICAL RELEVANCE: The maintenance requirements and the presence of prosthetic complications associated with marginal bone loss in the implant-retained bar and locator prostheses were evaluated. Complications occurred more frequently with the bar-supported removable implant prostheses.

Biomechanical investigation of maxillary implant-supported full-arch prostheses produced with different framework materials: a finite elements study.

PURPOSE: Four and six implant-supported fixed full-arch prostheses with various framework materials were assessed under different loading conditions. MATERIALS AND METHODS: In the edentulous maxilla, the implants were positioned in a configuration of four to six implant modalities. CoCr, Ti, ZrO2, and PEEK materials were used to produce the prosthetic structure. Using finite element stress analysis, the first molar was subjected to a 200 N axial and 45° oblique force. Stresses were measured on the bone, implants, abutment screw, abutment, and prosthetic screw. The Von Mises, maximum, and minimum principal stress values were calculated and compared. RESULTS: The maximum and minimum principal stresses in bone were determined as CoCr < ZrO2 < Ti < PEEK. The Von Mises stresses on the implant, implant screw, abutment, and prosthetic screws were determined as CoCr < ZrO2 < Ti < PEEK. The highest Von Mises stress was 9584.4 Mpa in PEEK material on the prosthetic screw under 4 implant-oblique loading. The highest maximum principal stress value in bone was found to be 120.89 Mpa, for PEEK in 4 implant-oblique loading. CONCLUSION: For four and six implant-supported structures, and depending on the loading condition, the system accumulated different stresses. The distribution of stress was reduced in materials with a high elastic modulus. When choosing materials for implant-supported fixed prostheses, it is essential to consider both the number of implants and the mechanical and physical attributes of the framework material.

Comparison of the Crestal Bone Loss Between Implant-Supported Prosthesis With Sinus Augmentation and Distal Cantilevered Implant-Supported Prosthesis Without Sinus Augmentation.

This study aimed to compare the crestal bone loss between a 2-implant-supported, noncantilevered 3-unit fixed partial prosthesis (TUFPP) with sinus augmentation and a 2-implant-supported, distal cantilevered TUFPP without sinus augmentation in the posterior maxilla having insufficient crestal bone. The study subjects were enrolled in 2 groups. Group 1 included patients with 2 implants: an anterior implant placed in the native bone and a posterior implant inserted with simultaneous sinus augmentation using a xenogenic bone graft to support a TUFPP. Group 2 included patients with 2 implants inserted in the native bone to support a distal cantilevered TUFPP. The crestal bone levels at the distal and mesial aspects of each implant were measured at baseline and 6-, 12-, and 24-month follow-up controls on panoramic radiographs. Fifty-two patients and 104 implants were included. There was a significant difference in distal crestal bone loss between anterior and posterior implants in group 1 at 6 months (P < .05) but not at 12 and 24 months (P > .05). Distal crestal bone loss was significantly increased in group 1 posterior implants compared to the group 2 posterior implants at 6 months (P < .05). There was no significant difference in mesial bone loss between the anterior and posterior implants in both groups at all follow-up controls (P > .05). There was also no significant mesial crestal bone loss in relation to the anterior and posterior implants of both groups at all follow-up controls (P > .05). Noncantilevered 2-implant-supported TUFPP with sinus augmentation may have similar medium-term crestal bone loss when compared to cantilevered 2-implant-supported TUFPP without sinus augmentation. Further prospective studies should be designed to compare the performance of the 2-implant-supported cantilevered TUFPP and 2-implant-supported TUFPP with sinus augmentation.

Comparison of four-implant-retained overdentures and implant-supported fixed prostheses using the All-on-4 concept in the maxilla in terms of patient satisfaction, quality of life, and marginal bone loss: a 2-year retrospective study.

OBJECTIVE: The purpose of the present study was to compare and assess maxillary edentulous patients treated with four-implant-retained overdentures and with implant-supported fixed prostheses using the All-on-4 concept in terms of patient satisfaction, oral health-related quality of life, and marginal bone loss. METHOD AND MATERIALS: Thirty-three patients treated with either maxillary four-implant-retained overdentures (n = 15) or with maxillary implant-supported fixed prosthesis using the All-on-4 concept (n = 18) were compared in terms of patient satisfaction, quality of life, and marginal bone loss. Independent sample t test was used to compare the two groups in terms of satisfaction, OHIP-14 scores, and marginal bone loss. The paired sample t test was used to compare bone loss at different time intervals. The comparison of marginal bone loss with regard to implant location was accomplished with the one-way ANOVA test. P values of < .05 were considered as statistically significant. RESULTS: No statistically significant differences were found between the two groups' OHIP-14 scores (P > .05). When patient satisfaction scores were evaluated, hygiene maintenance (P = .001) and pain scores (P = .001) were significantly higher in the implant-retained overdenture group than in the implant-supported fixed prosthesis group (P < .05). No statistically significant difference was observed between axial and tilted implants at both the 12-month (P = .59) and 24-month (P = .77) follow-up periods in the implant-supported fixed prosthesis group. CONCLUSION: Four-implant-supported fixed prostheses with the All-on-4 concept and four-implant-retained overdentures present similar marginal bone loss and quality of life scores after 2 years of function. However, patients found overdentures easier to clean but more painful in comparison with the fixed prosthesis.

Custom and prefabricated PolyEtherKetoneKetone (PEKK) post-core systems bond strength: Scanning electron microscopy evaluation.

The present study evaluated the bond strengths of prefabricated PolyEtherKetoneKetone (PEKK) posts, PEKK posts custom-configured according to root-canal size, and conventional fiber posts. A total of 30 maxillary incisors were randomly divided into three groups, as follows: Group 1: fiber posts; Group 2: prefabricated PEKK posts; Group 3; custom-made PEKK posts. Following endodontic treatment, post spaces were prepared, and posts were cemented with resin cement. Push-out bond strength testing was performed using a universal testing machine, and fractures modes were examined under a scanning electron microscope. Data were analyzed using One-way ANOVA and Tukey's HSD tests, with the level of significance set at .05. The highest bond-strength values in the cervical section were observed with the custom-made PEKK post (17.3470 MPa), whereas the highest bond-strength values in the middle and apical sections were observed with the conventional fiber posts (11.5375 MPa and 6.8625 MPa, respectively). Bond-strength values for all posts systems decreased in a cervical to apical direction. PEKK posts are a suitable alternative to fiber posts. Although custom-made PEKK posts demonstrated better bond strength than prefabricated PEKK posts, further studies are needed to evaluate their clinical performance.

Effects of implant-related variables on the marginal bone loss around dental implants.

OBJECTIVE: Marginal bone loss (MBL), a prognostic parameter for implant success, is associated with implant- and patient-related variables. The purpose of this study was to analyze the effects of the crown-to-implant ratio and independent factors of implant diameter, implant length, implant type, location, and platform switching on distal and mesial MBLs at the 6-, 12-, 24-, and 36-month recall sessions of single crown implant-supported restorations. METHOD AND MATERIALS: Radiographic and clinical data of patients treated with single crown implants were collected. MBL was measured at the baseline and recall sessions on panoramic radiographs. The crown-to-implant ratio was calculated by dividing the length of the crown by that of the dental implant. RESULTS: The crown-to-implant ratio had a moderately positive correlation with distal MBL at the 6-month recall session (P < .05, r = 0.469) and a weakly positive correlation at the 12- (P < .05, r = 0.220), 24- (P < .05, r = 0.214), and 36- (P < .05, r = 0.250) month recall sessions. Distal and mesial MBL did not significantly differ among the four implant types at any recall session (P > .05). The crown-to-implant ratio had no significant correlation with mesial MBL at the 12-, 24-, or 36-month recall session (P > .05), and a moderately positive correlation at the 6-month recall session (P < .001, r = 0.434). CONCLUSIONS: MBL was similar among different implant types in the short and medium terms. There was a positive correlation between distal MBL and the crown-to-implant ratio.

The Evaluation of the Relationship between Loading Time and Crestal Bone Loss around Dental Implants at 12 Months Control Evaluation after Loading.

The evaluation of the relationship between loading time and crestal bone loss around dental implants 12 months after loading was the objective of this study. All clinical and radiological data of patients treated with posterior mandibular implant-supported fixed dentures between January 4, 2013 and January 3, 2018 were retrieved from the archives. Loading time was recorded as the time between dental implant insertion and loading of the implant-supported restoration. The crestal bone levels of distal and mesial aspects of all implants were measured at postloading 12 months control evaluation on panoramic radiographs. Distal and mesial crestal bone loss values were recorded and averaged to obtain one mean value. The relationship between loading time and crestal bone loss was evaluated with statistical analysis. A total of 89 patients and 238 implants were included in the study. The loading time for each implant was recorded between a range of 0 and 401 days. A linear relationship was observed between loading time and crestal bone loss measured at 12 months control evaluation. The crestal bone loss at 12 months control evaluation after loading was significantly increased with the increase in the loading time after dental implantation (p < 0.05). The range of CBL was narrower between 100 and 200 days of loading time. The increase in loading time may cause increased crestal bone loss after 12 months function. Crestal bone loss at 12 months control evaluation is more predictable in dental implants loaded between 3 to 6 months after dental implant placement.

The effect of smoking on the marginal bone loss around implant-supported prostheses.

INTRODUCTION: Implantology has led to several changes in the planning process involved in the application of dental prostheses to diminish bone level changes along the margins of dental implants. However, the relationship between smoking and marginal bone loss around dental implants, supporting both fixed and removable prostheses has not been investigated. We hypothesize that the design of different prostheses alter the effects of smoking, which consequently affects the amount of supporting alveolar bone. METHODS: In this study, we included 137 implants in the 'implant-supported fixed prostheses' (ISFP) group (31 smokers, 106 non-smokers) and 94 implants (21 smokers, 73 non-smokers) in the 'implant-supported removable prostheses' (ISRP) group. The corresponding patients were examined in routine recall sessions conducted at 6, 12 and 24 months after the placement of the dental prostheses. The recorded clinical periodontal parameters were the presence/ absence of a plaque index, bleeding index, and the probing depths. These periodontal parameters were assessed in conjunction with marginal bone level measurements. Comparative bone level measurements were obtained from radiographical images at ×20 magnification using the CorelDraw 11.0 software program. Statistical analysis was performed using the SPSS Statistical Software version 21.0. RESULTS: The overall clinical parameters were found to be poorer in smokers than in non-smokers (p<0.05). In all the groups, time-dependent bone loss was observed. However, among the patients with ISRPs, smokers were associated with significantly greater marginal bone loss compared to patients with ISFPs (p<0.05). CONCLUSIONS: In smokers with dental ISRPs, the marginal bone loss rates are likely to reach critical levels. Therefore, after the placement of prostheses, strict recall periods with a dental professional should be observed, and their guidance should be implemented in order to monitor the health of the bones around the implants.

Effect of Smoking and Locations of Dental Implants on Peri-Implant Parameters: 3-Year Follow-Up.

BACKGROUND Smoking may be a risk factor for marginal bone loss (MBL) and oral mucosal inflammation surrounding dental implants. This retrospective study evaluated the effects of smoking on dental implants in patients with fixed implant-supported prostheses over a period of 36 months following loading. MATERIAL AND METHODS We assessed 120 patients (68 women, 52 men, ages 19-74 years (mean age: 55.10 years) with 315 implants. Implants were classified according to location in the upper and lower jaws and anterior (placed between canines) or posterior (placed between pre-molars and molars) as follows: 1=maxilla anterior, 2=maxilla posterior, 3=mandible anterior, 4=mandible posterior. We also measured MBL, plaque index (PI), sulcus bleeding index (SBI), and probing depth (PD). P-values less than 0.05 were considered statistically significant. RESULTS MBL was statistically greater in smokers (P<0.001) as compared to non-smokers in both jaws. MBL did not vary significantly by location in either group (smokers: p=0.415; non-smokers: p=0.175). Mean PI and PD scores were significantly higher in smokers as compared to non-smokers (P<0.001). A positive correlation was found between PI and PD scores in both groups. No statistically significant difference in SBI was observed between the 2 groups (P>0.05). CONCLUSIONS Smoking was associated with increases in marginal bone loss around implants, independent of their location in the jaws. Also, both plaque indices and probing depths were greater in smokers than in non-smokers.

Assessment of the Effect of Clinical Independent Risk Factors on Marginal Bone Loss in 2-Implant-Supported Locator-Retained Mandibular Overdentures.

The objective of this study is to evaluate the effect of clinical parameters of gender, age, implant length, implant diameter, interimplant distance, and locator height on marginal bone loss in 2-implant-supported locator-retained mandibular overdenture prostheses in 6, 12, and 24 recall sessions after loading. Clinical and radiographic data of patients who were treated between January 1, 2014, and January 4, 2018, were retrieved from the archives. The clinical data of gender, age, implant length, implant diameter, and locator height were recorded. The mesial and distal marginal bone levels of all implants and interimplant distances were determined at baseline and at 6-, 12-, and 24-month recall sessions on panoramic radiographs in a computer program. Statistical analysis was used to evaluate the effect of implant length, implant diameter, gender, age, interimplant distance, and locator height on marginal bone loss at the 6-, 12-, and 24-month control evaluations. A total of 57 patients with a mean age of 59.2 ± 9.8 years and 114 implants were included in the study. Among the aforementioned parameters, only the locator height had a major effect on the distal and mesial marginal bone loss (P < .05). A locators with a 4-mm height showed statistically significant distal and mesial marginal bone loss compared with locators with 2- and 3-mm heights in all control periods (P < .05). The locator with a 4-mm height generated more stress compared with locators with 2- and 3-mm heights, leading to marginal bone loss. The absence of oral hygiene evaluation was identified as a limitation of the study. Clinical parameters of gender, age, implant length, implant diameter, and interimplant distance did not seem to affect marginal bone loss in the study population of the current study.

Influence of nano alumina coating on the flexural bond strength between zirconia and resin cement.

PURPOSE: The purpose of this in vitro study is to examine the effects of a nano-structured alumina coating on the adhesion between resin cements and zirconia ceramics using a four-point bending test. MATERIALS AND METHODS: 100 pairs of zirconium bar specimens were prepared with dimensions of 25 mm × 2 mm × 5 mm and cementation surfaces of 5 mm × 2 mm. The samples were divided into 5 groups of 20 pairs each. The groups are as follows: Group I (C) - Control with no surface modification, Group II (APA) - airborne-particle-abrasion with 110 µm high-purity aluminum oxide (Al2O3) particles, Group III (ROC) - airborne-particle-abrasion with 110 µm silica modified aluminum oxide (Al2O3 + SiO2) particles, Group IV (TCS) - tribochemical silica coated with Al2O3 particles, and Group V (AlC) - nano alumina coating. The surface modifications were assessed on two samples selected from each group by atomic force microscopy and scanning electron microscopy. The samples were cemented with two different self-adhesive resin cements. The bending bond strength was evaluated by mechanical testing. RESULTS: According to the ANOVA results, surface treatments, different cement types, and their interactions were statistically significant (P<.05). The highest flexural bond strengths were obtained in nanostructured alumina coated zirconia surfaces (50.4 MPa) and the lowest values were obtained in the control group (12.00 MPa), both of which were cemented using a self-adhesive resin cement. CONCLUSION: The surface modifications tested in the current study affected the surface roughness and flexural bond strength of zirconia. The nano alumina coating method significantly increased the flexural bond strength of zirconia ceramics.