Relationship between Fixed Dental Crowns and Volatile Sulphur Compounds.

OBJECTIVES: The aim of this study was to investigate and compare the level of halitosis in patients with/without fixed crowns and in addition the influence of various crown parameters on halitosis was also explored. METHODS: In total, 96 subjects (fixed crowns = 52; no crowns = 44) participated in the study. The levels volatile sulphur compounds (VSCs) of hydrogen sulphide (H2S), methyl mercaptan (CH3SH), and dimethyl sulphide (CH3SCH3) were evaluated with breath samples using gas chromatography and used for classification as presence or absence of halitosis. The periodontal clinical parameters for all the participants as well as the crown parameters for participants with fixed crowns were also evaluated. Cross tabulation, Chi-square test, and one-way analysis of variance tests were used for the statistical analysis and comparisons. RESULTS: Breath samples revealed, 50 (52.1%) participants were suffering from halitosis. Out of VSCs, the level of CH3SCH3 (62.5%) was found to be the most prevalent. Significant correlations were observed between the presence of fixed crowns and oral halitosis (p < 0.001). Statistically significant difference in the concentration of H2S and CH3SH (p < 0.001) and no significance for CH3SCH3 (p = 0.075) between patients with/without fixed crowns was found. The presence of halitosis was more prevalent in the subjects with crown parameters (subgingival margin, over-contoured margin, open-crown margin, over-contoured and under-contoured crowns) considered clinically defective/unacceptable (p < 0.05). CONCLUSIONS: Presence of fixed dental crowns significantly contributes to the oral halitosis. Dental crowns with defects significantly impair the hygienic conditions and oral microflora resulting in high prevalence of halitosis.

Dentin bond strength of bioactive cement in comparison to conventional resin cement when photosensitized with Er,Cr:YSGG Laser.

OBJECTIVE: The purpose of the present study was to assess dentin shear bond strength (SBS) and mode of bond failure of bioactive cement (BA) in comparison to conventional resin cement when photosensitized by Er,Cr: YSGG Laser (ECL). METHODS: The present in-vitro study was carried out from March 2019 to May 2019. Sixty permanent non-carious, intact, non-fractured molars were isolated and mounted vertically in acrylic resin. Buccal surface of each molar tooth was ground, polished and surface treated with ECL. Ketac conditioner was applied on the surface washed and air dried surface. Tetric -N-Bond adhesive was applied on forty-five samples and light cured. The specimens were allocated into four groups (n=15) according to the type of cement used i.e., Calibra (C), BA, Variolink II (V) and Maxcem-Elite (ME). For SBS testing was performed using the universal testing machine. Eight samples from each group were assessed for modes of failure. Means and standard deviations were compared using analysis of variance (ANOVA) and Tukey's post hoc test at a significance level of p < 0.05. RESULTS: The highest mean SBS was observed in group ECL-C (21.55±3.08). The lowest mean SBS was displayed in group ECL-ME (14.25±3.55). Mean SBS values for group ECL-C (21.55±3.08) and group ECL-V (20.74±4.15) were comparable (p <0.05). Similarly, SBS values of group ECL-BA (15.48±3.62) and group ECL-ME (14.25±3.55) were comparable (p <0.05). CONCLUSION: Dentin surface conditioned with Er,Cr: YSGG and bonded to C and V cements exhibit favourable bond strength values.

Survival Rates of Short Dental Implants (≤ 6.5 mm) Placed in Posterior Edentulous Ridges and Factors Affecting their Survival after a 12-Month Follow-up Period: A Systematic Review.

PURPOSE: Dental implant placement in atrophic ridges is challenged by availability of bone and proximity to vital structures. Although short dental implants have been considered favorable, there is no consensus regarding their long-term survival and factors affecting it. This systematic review addressed the focused question, "What is the survival rate of short dental implants (SDI; length ≤ 6.5 mm) placed in posterior edentulous ridges without any ridge augmentation procedures and followed up for 12 months post-prosthetic loading, and what are the factors affecting their survival?" MATERIALS AND METHODS: Based on a search of the indexed literature, 51 studies fulfilling the inclusion criteria were quantitatively reviewed. Overall SDI survival and factors influencing survival, such as anatomic location, surgical protocol, time of loading, type of prosthesis retention, nature of prosthesis, implant stability, crown-to-implant ratio (C/I ratio), and marginal bone loss at follow-up were evaluated. SDI survival based on clinical factors was compared to overall survival using odds ratio (OR), and continuously distributed data were evaluated using Pearson's correlation (P < .05). RESULTS AND CONCLUSION: Based on this review, SDI placed in edentulous posterior regions of the maxilla and mandible have survival rates (96.45%) similar to those of conventional-length implants after a follow-up period of 12 months post-prosthetic loading. Except for smaller implant diameter (OR = 1.59, 95% confidence interval [CI] = 1.03-2.43, P < .05), screw-retained restorations (OR = 2.11, 95% CI = 1.25-3.57, P < .01), and C/I ratio ≥ 2 (Pearson's R = -0.694, P < .01), other variables relating to implant surgery, prosthetic loading, nature and type of prosthesis, and follow-up did not significantly affect SDI survival.

Effect of the Unfilled Space Size of the Abutment Screw Access Hole on the Extruded Excess Cement and Retention of Single Implant Zirconia Crowns.

PURPOSE: To evaluate in vitro the effect of the size of the unfilled space of the abutment screw access hole on the amount of extruded excess cement and the retention of zirconia copings. MATERIALS AND METHODS: Twelve dental implant replicas were attached to the corresponding abutments and embedded in acrylic resin blocks. A total of 36 CAD/CAM zirconia copings were fabricated by one technician using the standard technique. Abutments were divided into group I: the entire screw access channel was completely filled (nonspaced); group II: 1-mm-spaced; and group III: 2-mm-spaced. The copings were air-abraded and temporarily cemented under constant load of 60 N for 10 minutes. The excess cement was calculated as the difference between the post-cementation and post-excess-removal weights using a digital scale. Retention test was performed by a universal testing machine at a 0.5 mm/min crosshead speed. The ultimate force and tensile strength required for separation were recorded. One-way ANOVA and Tukey's test were used for statistical analysis at p ˂ 0.05. RESULTS: The average amount of extruded cement in groups 1, 2, and 3 was 33.48 ± 1.55, 23.05 ± 5.48, and 15.58 ± 5.98 mg, respectively. Multiple comparisons showed significant differences in the amount of extruded excess cement between the three groups (p ˂ 0.001). The maximum load at decementation in groups 1, 2, and 3 was 98.8, 87.5, and 88.6 N, respectively. Groups 1, 2, and 3 separated at 6.90 ± 1.2, 6.12 ± 0.7, and 6.21 ± 0.9 MPa, respectively, with no significant differences between them. CONCLUSIONS: The amount of extruded excess cement was reduced by more than half when a 2-mm space of the screw access hole was left unfilled in comparison to the nonspaced counterpart. The retention of zirconia copings was not affected by the reported technique.

Effect of Er,Cr:YSGG Laser and Ascorbic Acid on the Bond Strength and Microleakage of Bleached Enamel Surface.

BACKGROUND: The available evidence of Er,Cr:YSGG lasers on bleached enamel is limited and controversial. It is assumed that Er,Cr:YSGG laser will be effective in reversing the effect of bleaching on adhesive bond integrity of enamel to resin composite. OBJECTIVE: The study aimed to evaluate the efficacy of Er,Cr:YSGG laser on bond strength and microleakage of bleached enamel. MATERIALS AND METHODS: From the 80 samples, 60 samples were bleached (40% hydrogen peroxide) and divided into three subgroups. Twenty bleached samples in each subgroup were exposed to 10% sodium ascorbate (Gp A), Er,Cr:YSGG laser (50 Hz and 4.5 W) (Gp L), and no treatment (Gp B), respectively. Twenty samples were not bleached (Control-C). Using etch and rinse technique, resin composite was built-up on enamel and photopolymerized. Ten specimens in each group were tested for shear bond strength at a crosshead speed of 1 mm/min. Ten specimens in each group were tested for microleakage using 2% methylene blue. Data were analyzed using analysis of variance (ANOVA) and Tukey post hoc multiple comparisons test. RESULTS: The mean bond strength of specimens in group L (30.83 ± 1.7000) was comparable with group A (31.38 ± 2.03) and was significantly higher than bleached specimens (9.49 ± 0.86) (p < 0.001). The highest mean microleakage values were observed in bleached group (630.32 ± 156.58). The mean microleakage among control (36.66 ± 27.33) and laser group specimens (55.32 ± 34.98) was comparable (p > 0.05). CONCLUSIONS: Treatment of bleached enamel with erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) laser showed a significant reversal effect on the enamel bond strength and microleakage scores. CLINICAL SIGNIFICANCE: Er,Cr:YSGG laser (50 Hz, 4.5 W) treatment has the potential to restore the bond strength of bleached enamel to resin composite.

Influence of space size of abutment screw access channel on the amount of extruded excess cement and marginal accuracy of cement-retained single implant restorations.

STATEMENT OF PROBLEM: The detrimental effect of extruded excess cement on peri-implant tissue has been well documented. Although several techniques have been proposed to reduce this effect by decreasing the amount of extruded cement, how the space size of the abutment screw access channel (SAC) affects the amount of extruded cement and marginal accuracy is unclear. PURPOSE: The purpose of this in vitro study was to evaluate the effect of the size of the unfilled space of the abutment SAC on the amount of extruded excess cement and the marginal accuracy of zirconia copings. MATERIAL AND METHODS: Twelve implant replicas and corresponding standard abutments were attached and embedded in acrylic resin blocks. Computer-aided design and computer-aided manufacturing (CAD-CAM) zirconia copings with a uniform 30-µm cement space were fabricated by 1 dental technician using the standard method. The copings were temporarily cemented 3 times at different sizes of the left space of the SAC as follows: the nonspaced group (NS), in which the entire SAC was completely filled, the 1-mm-spaced group (1MMS), and the 2-mm-spaced group (2MMS). Abutments and crowns were ultrasonically cleaned, steam cleaned, and air-dried. The excess cement was collected and weighed. To measure the marginal accuracy, 20 measurements were made every 18 degrees along the coping margin at ×300 magnification and compared with the pre-cementation readings. One-way ANOVA was calculated to determine whether the amount of extruded excess cement differed among the 3 groups, and the Tukey test was applied for multiple comparisons (α=.05). RESULTS: The mean weights (mg) of extruded excess cement were NS (33.53 ±1.5), 1MMS (22.97 ±5.4), and 2MMS (15.17 ±5.9). Multiple comparisons showed significant differences in the amount of extruded excess cement among the 3 test groups (P<.001). The mean marginal discrepancy (µm) of the pre-cemented group (29.5 ±8.2) was significantly different (P<.01) from that of the NS (72.3 ±13.7), the 1MMS (70.1 ±19), and the 2MMS group (70.1 ±18.8). No significant differences were found in marginal accuracy among the 3 test groups (P=.942). CONCLUSIONS: Within the limitations of this in vitro study, leaving a 2-mm space in the SAC reduced the amount of extruded excess cement by 55% in comparison with the nonspaced abutments. However, no effect was found on the marginal accuracy of zirconia copings.

Comparison of clinical and radiographic parameters around short (6 to 8 mm in length) and long (11 mm in length) dental implants placed in patients with and without type 2 diabetes mellitus: 3-year follow-up results.

OBJECTIVE: To compare the clinical and radiographic parameters around short (6 to 8 mm in length) and long (11 mm in length) dental implants placed in patients with and without type 2 diabetes mellitus (T2DM). MATERIAL AND METHODS: Forty-five male patients with T2DM (Group-1) and 42 male non-diabetic controls (Group-2) who had undergone implant therapy in the posterior mandible were included. Depending upon the length of the implant, patients were divided into two subgroups: (a) patients with short implants (6-8 mm long) and (b) patients with long implants (11 mm long). Peri-implant plaque index (PI), bleeding on probing (BOP), probing depth (PD) and crestal bone loss (CBL) were measured at 18 and 36 months of follow-up in both groups. Hemoglobin A1c (HbA1c) levels were measured at baseline and after 18 and 36 months of follow-up in both groups. P-values less than 0.05 were considered statistically significant. RESULTS: The mean age of patients in groups 1 and 2 was 42.5 and 40.6 years, respectively. The mean HbA1c levels at baseline among patients in groups 1 and 2 were 7.7% and 4.5%, respectively. At 18 and 36 months of follow-up, the mean HbA1c levels among patients in groups 1 and 2 were 6.6% and 4.5% and 6.5% and 4.4%, respectively. The mean duration of T2DM among patients that received short and long implants was 4.3 years and 4.1 years, respectively. There was no significant difference in PI, BOP, PD and CBL around implants placed in both groups at 18 and 36 months of follow-up. Success rate of short and long dental implants was 100% in both groups. CONCLUSION: Short implants can demonstrate clinical and radiographic stability in a manner similar to conventional long implants in patients with and without T2DM. The role of oral hygiene and glycemic maintenance in this scenario cannot be disregarded.

Dental Implant Length and Diameter: A Proposed Classification Scheme.

PURPOSE: To propose a length-and-diameter-based classification scheme for dental implants to standardize terminology in the dental literature and communication between interested parties. MATERIALS AND METHODS: This study was mainly based on searching two major resources: published scientific research papers and 14 of the most popular dental implant manufacturers. Indexed databases were searched from January 2004 up to and including February 2016 using the keywords "dental implant length" and "dental implant diameter." Retrieved titles and abstracts were screened, and related full-text articles were reviewed. Full-text articles that clearly stated the terms and measurements of implants used were included and considered for proposing this classification scheme. RESULTS: The initial search for implant diameter and length yielded 1007 and 936 articles, respectively. A total of 85 studies (41 about diameter, 44 about length) were selected and reviewed. The remaining studies (966 about diameter, 892 about length) that did not abide by the eligibility criteria were excluded. The terms "long," "short," "standard," "wide," and "narrow" were the most commonly used terms in the literature. A classification scheme for implants by diameter and length was proposed. CONCLUSIONS: Indexed publications contain a variety of terms used by authors to describe diameter and length of dental implants without conformity and standardization. The classification scheme proposed in this article could serve as a reference for interested parties.

Soft tissue changes and crestal bone loss around platform-switched implants placed at crestal and subcrestal levels: 36-month results from a prospective split-mouth clinical trial.

OBJECTIVE: The aim of the present 36-month prospective split-mouth clinical trial was to investigate the peri-implant soft tissue changes and crestal bone loss (CBL) around delayed loaded platform-switched implants placed at crestal and subcrestal levels. MATERIAL AND METHODS: Twenty-three individuals with bilaterally missing either mandibular first or second molars were included. The test and control sites were defined as follows: (i) test sites: implants placed 2 mm below the alveolar crest (subcrestal); (ii) control sites: implants placed at bone level (crestal). Forty-six implants (23 implants in test sites and 23 in control sites) were placed in the center of the healed alveolar ridge in the posterior mandible. Peri-implant bleeding on probing (BOP), probing depth (PD ≥ 4 mm), and CBL was compared at 6, 18, and 36 months of follow-up. P < 0.05 was considered statistically significant. RESULTS: Sixteen males and seven females with a mean age of 43.5 years (29-50) were included. In the control group (n = 23), the highest mean percentage of sites that showed BOP and PD ≥ 4 mm were at 6 months (7.4% and 1.4%, respectively). In the test group (n = 23), the highest mean percentage of sites that showed BOP and PD ≥ 4 mm were at 6 months (2.4% and 1.2%, respectively). The total amount of CBL around crestal and subcrestal implants after 36 months of loading was 0.45 ± 0.2 and 0.3 ± 0.2 mm, respectively. At all follow-up intervals, all intragroup and intergroup comparisons showed no significant differences in BOP, PD ≥ 4 mm, and CBL around implants placed at crestal and subcrestal levels. CONCLUSION: Up to 36 months of follow-up, soft tissue parameters and crestal bone levels can remain equally stable around dental implants placed at crestal and subcrestal levels. The need for long-term follow-up clinical trials is also emphasized.

Tooth Numbering System in Saudi Arabia: Survey.

OBJECTIVE: There were four aims of the current study: (1) to find the most commonly used Tooth Numbering System (TNS) in Saudi Arabia in both academic and non-academic institutions, (2) to identify the most commonly taught TNS in dental colleges, (3) to understand the reasons why dental practitioners prefer to use a specific TNS, and (4) the consequences of using more than one TNS. MATERIALS AND METHOD: Between May 2014 and May 2015, a self-administered questionnaire containing 21 questions was randomly distributed to 121 individuals (20 deans of dental colleges and 101 heads of governmental dental centers). RESULTS: The most commonly used TNS is the Fédération Dentaire Internationale (FDI) TNS for both primary and permanent dentitions in both academic and non-academic institutions, followed by the Palmer TNS and then the Universal TNS. CONCLUSION: The FDI TNS proved to be the most taught TNS in dental colleges in Saudi Arabia. It is advised that the FDI TNS be implemented as a unified system in Saudi Arabia due to the advantages of this particular TNS and the benefits of using one single TNS.