Local and Systemic Effects of Cyclosporine A on the Severity of Gingival Overgrowth in Post-Transplant Renal Patients.

BACKGROUND: Cyclosporine A (CsA) is a potent immunosuppressant widely used to prevent renal post transplantation rejection. Gingival overgrowth (GO) is among various side effects of the long-term administration of CsA. Up to 90% of the patients under CsA therapy has been reported to develop CsA-induced GO. OBJECTIVES: The aim of the present prospective pilot study is to determine the local and systemic effects of Cyclosporine A (CsA) on the severity of gingival overgrowth and its relationship with periodontal parameters in post-transplant renal patients. METHODS: Twenty post-transplant renal patients, 12 females and 8 males, presenting gingival overgrowth were selected from Rizk Hospital's clinic in Beirut. Patient's CsA plaque levels were evaluated when CsA is administered by syrup and capsules mode. Periodontal parameters including gingival overgrowth, papillary bleeding, plaque and gingival indices were assessed for all patients. RESULTS: Plaque concentration CsA levels, when administered in syrup mode, affected significantly the severity of gingival overgrowth as opposed to the administration by capsule mode. Significant correlations between severity of gingival overgrowth on one hand and plaque index, gingival index, and papillary bleeding index on the other hand were only observed in the Capsule group but not in the syrup group. A significant relationship was established between the severity of gingival overgrowth and all periodontal parameters (gingival, papillary and plaque). CONCLUSION: The present study underlines CsA dental plaque local effect, as a co-factor, in the development of gingival overgrowth. Cyclosporine plaque accumulation acts as a reservoir in the gingival inflammation and the periodontal indices seem to be the most accurate parameters associated with gingival overgrowth severity. Plaque CsA concentrations could be considered as a risk factor for inflammation and gingival overgrowth depending on CsA delivery mode in renal transplant patients.

Factors Affecting Implant Stability Quotients at Immediately and Conventionally Loaded Implants in the Posterior Maxilla: A Split-Mouth Randomized Controlled Trial.

PURPOSE: To assess primary and secondary stability of variable-thread tapered implants in the posterior maxilla and analyze the impact of various factors on implant stability quotients (ISQs). MATERIALS AND METHODS: Twenty-six subjects received 3-4 adjacent implants in the maxillary premolar-molar sextants to replace bilateral tooth loss. The implants on one side were immediately loaded with a provisional fixed prosthesis regardless of their primary stability. The contralateral control implants were conventionally loaded. Bone quality was subjectively recorded and primary stability was assessed by means of insertion torque values (ITVs) and ISQs in 4 directions. Secondary stability was measured by ISQ at definitive prosthesis delivery (3-3.5 months postoperatively), and 12 months after definitive loading. The impact of measurement direction, loading protocol, time, site-related (bone quality, implant position, crestal buccal bone thickness, apical cortical anchorage), and implant-related (implant dimensions, abutment height) variables on ISQs was assessed. RESULTS: For logistic reasons, ISQs were obtained for only 18 patients with 60 test and 60 control implants. Most of the implants (82%) at baseline had their lowest ISQ on the buccal aspect. There were no significant differences between ISQs measured in the buccal and palatal directions, or between ISQs in the mesial and distal directions. The mean of buccal and palatal ISQs was significantly lower than the mean of the 2 interproximal measurements at all evaluation periods. ISQs were not significantly different between the 2 loading groups at any time point. All implants showed a time-dependent increase in ISQs. Baseline ISQ correlated weakly with bone quality and ITV. None of the variables had a significant impact on baseline ISQs, except for implants in second molar sites which showed poorer primary stability than first premolars. CONCLUSION: Measurement direction and time are the most significant parameters affecting ISQs of variable-thread tapered implants in the posterior maxilla.

Evaluation of the Papillary Gingival Vasculature in Smokers and Nonsmokers with Chronic Periodontitis: A Clinical In Vivo Study.

AIM: Cigarette smoking has been recognized as an important risk factor in periodontal diseases. One of the suggested mechanisms behind this association is that nicotine alters the microcirculation and causes vasoconstriction and reduced blood flow through the periodontal tissues. Scarce information is currently available relative to the microvascular alterations associated with smoking and the distribution of capillaries through the various areas of the gingival tissues. The aims of this study were to assess, in human interproximal gingival biopsies, the number and diameter of gingival capillaries in periodontally affected smokers and nonsmokers using the CD34 immunohistochemical staining method. The pattern of distribution of vessels in the different areas of the gingival tissues was also assessed. MATERIALS AND METHODS: Systemically healthy patients with moderate chronic periodontitis and ranging in age between 30 and 60 years were recruited for the study from the patient population attending the Periodontology Department of the Faculty of Dental Medicine at the Lebanese University of Beirut. The patients were selected to have a group of 10 patients (Group SP) of smokers (>10 cigarettes/day for the last 10 years) and a second group (Group NP) consisting of nonsmoking periodontally affected patients. Three to four weeks following initial preparation, one interproximal gingival biopsy was obtained from each patient. Immunohistochemical staining with CD34 mouse monoclonal antibody was used to identify the endothelial cells of the blood vessels within each sample. Twelve biopsy samples (five in Group NP and seven in Group SP) were chosen for the measurement of the number and diameter of vessels in three regions of the connective tissue of the biopsy under a blinded protocol. RESULTS: In the two groups, the quantitative distribution of small, medium, and large vessels followed a similar trend with the number of small vessels being significantly greater than both medium and large vessels. Small vessels prevailed in the peripheral regions, whereas large vessels were more abundant in the deeper connective tissue areas. The total number of vessels seemed unaffected by chronic cigarette smoking in both groups in the entire biopsy area and in the separate connective tissue regions. Quantitative alteration in the total number of gingival capillaries was not observed in chronic smokers. A redistribution of small and large vessels in the superficial and deeper connective tissue areas of the gingival papilla was noted as a result of smoking in periodontal patients. CONCLUSION: The quantitative distribution of small, medium, and large vessels follows a similar trend with the content in small vessels being significantly more important than both medium and large vessels. Smoking and periodontitis result in a redistribution of small and large vessels in the superficial and deeper connective tissue areas of the gingival papilla compared to nonsmoking periodontal patients. The significance and clinical implications of such rearrangement of vasculature within the gingival tissue need to be further investigated.

Effect of Simulated Mastication on the Retention of Locator Attachments for Implant-Supported Overdentures: An In Vitro Pilot Study.

PURPOSE: Limited information is currently available relative to the effect of masticatory loads on the retentive properties of Locator attachments. The aims of this in vitro study were to assess and compare the effect of simulated mastication on the retention of white, pink, and blue Locator inserts for overdentures retained by 2 implants. MATERIALS AND METHODS: Thirty specimens simulating a nonanatomic edentulous flat ridge with two implants and an overdenture were divided into 3 groups according to the color of the fitted insert: transparent clear group (n = 10), pink group (n = 10), and blue group (n = 10). Retention forces were measured in an axial direction initially and after 100,000 cycles of simulated masticatory loads. One-way ANOVA followed by Tukey's post hoc tests were used to compare retention values and percentage retention loss between the 3 groups with significance set at p = 0.05. RESULTS: The 3 groups presented significant differences in retention at baseline (9.95 ± 1.91 N, 15.43 ± 4.08 N, and 41.73 ± 9.29 N for the blue, pink, and clear groups, respectively) and after simulated mastication (6.37 ± 2.64 N, 14.00 ± 3.89 N, 38.20 ± 5.11 N for the blue, pink, and clear groups, respectively). Within the same group, cyclic loading did not significantly affect retention in the clear and pink groups, while the blue inserts showed a significant retention loss (-37%) after loading. CONCLUSIONS: The results suggest that short-term simulated mastication affects the extra-light blue inserts but not the more-retentive inserts.

Immediate versus conventional loading of variable-thread tapered implants supporting three- to four-unit fixed partial dentures in the posterior maxilla: 3-year results of a split-mouth randomised controlled trial.

PURPOSE: To compare the 3-year outcomes of immediately loaded and one-stage conventionally loaded variable-thread tapered implants in the posterior maxilla. MATERIALS AND METHODS: This study was designed as a split-mouth randomised controlled trial. Twenty-six patients attending the postgraduate Periodontics Department at the Lebanese University, and missing teeth bilaterally in the posterior maxilla were randomised. All patients received three to four implants in each of the posterior sextants. The implants on one side were immediately loaded with a provisional resin fixed partial denture on definitive multi-unit abutments regardless of their primary stability. The implants in the contralateral side received definitive multi-unit abutments according to the one-stage unloaded protocol. Three to 3.5 months following implant placement, the implants were restored with metal-ceramic fixed prostheses. Outcome measures were implant and prosthesis failure rates, complications, and peri-implant bone level changes up to 3 years following delivery of the definitive prosthesis. The clinical outcomes and radiographic measurements were performed by a single outcome assessor blinded to the type of interventions. RESULTS: Two patients dropped out prior to the delivery of definitive prostheses. The results were analysed using a per-protocol analysis and included 24 patients. Four implants supporting a four-unit immediately loaded prosthesis failed in one patient, 3 months following definitive prosthesis. In the same patient, the three contralateral conventionally loaded implants failed 14 months after definitive prosthesis. There were no significant differences in the proportions of implant and prosthesis failures at 3 years (difference = 0%; 95% CI 0.0% to 14.2%; P = 0.999). Peri-implantitis was diagnosed at two adjacent conventionally loaded implants in one patient at the 3-year examination. In the immediately loaded group, four early minor prosthetic complications occurred during the provisionalisation phase. Following delivery of the definitive prostheses, one minor ceramic fracture was observed in each of the implant groups. The difference in the rate of complications between the two interventions was not statistically significant at 3 years (difference = 13%; 95% CI 3.4% to 27.7%; P = 0.453). The 3-year peri-implant marginal bone level changes were evaluated in 23 patients (77 immediately loaded and 76 conventionally loaded implants). On average, patients lost 0.79 (0.62) mm at the immediately loaded and 0.91 (0.82) mm at the conventionally loaded implants, the difference being statistically not significant (difference = 0.12 mm; 95% CI -0.31 to 0.55 mm; P = 0.590). The 3-year marginal bone level changes were not significantly different between smokers (n = 12) and non-smokers (n = 11) (difference = 0.19 mm; 95% CI -0.24 to 0.62 mm; P = 0.382). CONCLUSIONS: Immediate loading of three- to four-unit fixed partial prostheses supported by variable-thread implants in the posterior maxilla can achieve similar 3-year results to one-stage conventionally loaded implants.

Effect of patient- and surgery-related factors on supracrestal tissue reestablishment after crown lengthening procedure.

OBJECTIVES: The standard application of a mean value of 2.04 mm for the biologic width has been demonstrated to result in inconsistent amounts of tooth extension following a crown lengthening procedure. Biologic width has been replaced by the supracrestal gingival tissue dimension, which includes the biologic width and sulcular depth. The question whether supracrestal gingival tissue dimension established at tissue maturation following a crown lengthening procedure is not significantly different from the presurgical dimension has not been fully answered. The primary objectives of the present prospective clinical study were to compare the preoperative and the 24-week dimensions of supracrestal gingival tissue following a crown lengthening procedure and assess the alterations in gingival margin position. A secondary objective was to assess selected patient- and surgery-related factors on supracrestal gingival tissue reestablishment. METHOD AND MATERIALS: Twenty adult systemically healthy patients requiring a crown lengthening procedure were recruited for the study. A crown lengthening procedure was performed at 33 teeth and the patients were followed up to 24 weeks. The following parameters were recorded using customized stents for measurement reproducibility: stent-gingival margin (baseline, immediately after surgery, and at 6, 12, and 24 weeks), stent-bottom of sulcus (baseline and at 6, 12, and 24 weeks), stent-bone crest (baseline, at completion of osseous resection, and at 24 weeks), bone thickness (baseline, postsurgery), buccal gingival thickness (baseline, 24 weeks), and radiographic interproximal bone width (baseline, 24 weeks). Supracrestal gingival tissue, crown extension, and distance between the immediate postoperative position of the gingival margin relative to the contoured bone crest (F) were calculated. RESULTS: There were no statistically significant differences between supracrestal gingival tissue measurements at baseline and at 24 weeks for any of the four tooth sides. Crown extension remained significantly increased at 24 weeks compared to baseline for all sides, with the largest amounts of gingival creeping mesially and distally. A highly significant positive correlation (r = 0.97, P < .001) was demonstrated between flap positioning and stability of the gingival margin during the healing period. The closer was the F measurement to baseline supracrestal gingival tissue dimension, the less change in gingival margin was observed. CONCLUSIONS: The preliminary results of this investigation suggest the following: The presurgical supracrestal gingival tissue dimension can be used as a guideline measurement in crown lengthening procedures as it is reestablished with a similar apico-coronal dimension 24 weeks postoperatively; and crown extension is stable when the distance between the sutured gingival margin and the contoured osseous crest is similar to the preoperative supracrestal gingival tissue dimension.

Changes in Keratinized Tissue Width Following Connective Tissue Grafts and Diode Laser- vs Blade-Gingivoplasty.

The objectives of this study were to clinically and histologically assess the capacity of bilaminar subepithelial connective tissue grafts (SCTGs) alone or in combination with gingivoplasty (Gv) to increase the keratinized gingiva width (KGW) in contralateral mandibular sites lacking KG (10 patients, 42 sites). The effects of Gv timing (1 vs 2 months) and technique (blade vs laser) were also evaluated. SCTGs alone resulted in mean KGW increase of 0.1 to 0.7 mm. Laser-Gv significantly increased KGW by an additional 1.9 mm at 4 months postabrasion as opposed to 0.9 mm achieved with blade-Gv. Histologically, laser-treated sites displayed parakeratinization with more pronounced rete pegs than observed in blade-abraded sites.

In Vitro Effect of Mastication on the Retention and Wear of Locator Attachments in a Flat Mandibular Ridge Model.

PURPOSE: The effect of masticatory loads on the retention of overdenture attachments is poorly documented. The aim of this in vitro study is to assess the effect of simulated mastication on the retentive properties and dimensions of Locator inserts. MATERIALS AND METHODS: 30 specimens simulating nonanatomic edentulous flat ridges with two implant replicas each were fabricated. Overdenture units were connected to the implants with Locator attachments and 3 types of inserts: transparent (Group T; n = 10 pairs), pink (Group P; n = 10 pairs), and blue (Group B; n = 10 pairs). The overdenture units were subjected to simulated bi-axial masticatory loads of 68.6 N. Locator retention was assessed using axial dislodging forces at baseline (T0) and following 100,000 (T1) and 200,000 (T2) masticatory cycles. The inner diameter of the insert (XY) and the diameter of the central core (AB) were measured under stereomicroscope at T0 and T2. Retention changes and dimensional variations of the inserts were statistically analyzed. RESULTS: The 3 groups showed significantly different retentions with the highest values recorded for group T followed by group P, and finally group B at T0, T1, and T2. Groups T and P were not affected by loading while group B showed a significant mean retention loss from T0 to T1. XY and AB were significantly different between the 3 color-coded inserts at baseline and at T2. No correlation could be established between retention changes and dimensional variations of the 3 types of inserts. CONCLUSIONS: Within the limitations of this in vitro study, simulated mastication seems to significantly affect the extra-light blue Locator inserts but not the more-retentive ones. The transparent and pink inserts may require less frequent replacements and could therefore be recommended under clinical conditions.

Insertion Torque of Variable-Thread Tapered Implants in the Posterior Maxilla: A Clinical Study.

PURPOSE: Primary stability is a key factor for successful implant osseointegration, especially in poor bone quality and early/immediate loading. In the immediate loading protocol, insertion torque values (ITVs) have been suggested to be the most valid prognostic factor for osseointegration of maxillary implants. The objectives of this study were to: (1) evaluate ITVs achieved by a variable-thread tapered implant in the posterior maxilla; and (2) assess the impact of bone quality, implant dimensions, bicortical anchorage, and implant location on ITVs. MATERIALS AND METHODS: Twenty-six adult, systemically healthy patients received 173 variable-thread tapered implants in maxillary premolar and molar healed edentulous sites with a minimum subsinus height of 8 mm. Implant sites were prepared using the bone-quality adjusted drilling sequence according to manufacturer's recommendations. Bone quality was recorded subjectively during drilling based on Misch criteria (D1-D4), and ITVs were measured with a manual torque wrench. Univariate and multivariate analyses were performed at the 0.05 significance level. RESULTS: First and second molar sites accounted for 46.8% of all implants. D4 bone was encountered in 61.3% of the sites. Most of the implants were 4.3 mm in diameter (59.5%), and lengths of 11.5 and 13 mm were most commonly used (75.2%). Approximately half of the implants were associated with apical cortical anchorage (51.4%). The overall mean ITV was 44.5 ± 23.0 Ncm, with 65.5 ± 15.6 Ncm, 55.5 ± 19.6 Ncm, and 36.6 ± 21.7 Ncm for D2, D3, and D4 bone, respectively. Bone quality and implant location significantly affected ITVs, while implant dimensions and apical cortical anchorage did not. CONCLUSIONS: ITVs of variable-thread implants were significantly influenced by variations in bone quality and implant position in the posterior maxilla. Despite the influence of bone quality on primary stability, the mean ITVs attained with variable-thread tapered implants in poor bone quality were within the recommended range for immediate loading.

Comparison of fit accuracy of pressed lithium disilicate inlays fabricated from wax or resin patterns with conventional and CAD-CAM technologies.

STATEMENT OF PROBLEM: The use of resin patterns to produce partial coverage restorations is poorly documented. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit accuracy of lithium disilicate glass-ceramic inlays obtained from wax or resin patterns and fabricated with digital and conventional techniques. MATERIAL AND METHODS: A dentoform mandibular first molar was prepared for a mesio-occlusal ceramic inlay. Six groups of 15 inlays were obtained by conventional impression and manual wax (group CICW) or resin patterns (group CICR); conventional impression, laboratory scanning of the stone die, CAD-CAM milled wax (group CIDW), or polymethylmethacrylate (PMMA) blocks (group CIDR); and scanning of the master preparation with an intraoral scanner, CAD-CAM milled wax (group DSDW), or PMMA blocks (DSDR). The same design was applied to produce the wax and PMMA patterns in the last 4 groups. The replica technique was used to measure marginal and internal fit under stereomicroscopy. Mixed-model ANOVA was applied to assess differences according to the techniques, materials, and discrepancy location (α=.05). RESULTS: The results demonstrated significant effects of the technique (P<.001), material (P=.009), and discrepancy location (P<.001) on fit measurements. Marginal discrepancy was only affected by the technique (P<.001), with the digital approaches yielding the smallest marginal discrepancy (23.5 ±3.6 µm), followed by the conventional digital techniques (31.1 ±5.6 µm) and finally by the conventional (42.8 ±7.2 µm) techniques. Internal fit was significantly influenced only by the material with lower discrepancy in wax (75.2 ±9.0 µm) than in resin patterns (84.7 ±15.1 µm). The internal discrepancy was significantly larger than the marginal discrepancy in all groups (P<.001). CONCLUSIONS: Inlays generated from conventional wax and resin patterns tend to show higher marginal discrepancies than conventional digital and full digital patterns. Wax and resin materials yield similar marginal fit accuracies irrespective of the impression/manufacturing technique. Better internal fit was shown in wax than in resin patterns, regardless of the technique.

Immediate vs conventional loading of variable-thread tapered implants supporting three- to four-unit fixed partial dentures in the posterior maxilla: 1-year interim results of a split-mouth randomised controlled trial.

PURPOSE: To compare the outcome of immediately loaded and one-stage conventionally loaded variable-thread tapered implants in the posterior maxilla. MATERIALS AND METHODS: This study was designed as a split-mouth randomised controlled trial. Twenty-six patients missing teeth bilaterally in the posterior maxilla received three to four implants in each of the posterior sextants. Bone quality was recorded based on Misch criteria (D1-D4) and insertion torque values were measured using a manual wrench. The implants on one side were immediately loaded with a temporary resin fixed partial denture on definitive multi-unit abutments. The implants in the contralateral side received definitive multi-unit abutments according to the one-stage unloaded protocol. Three to 3.5 months following implant placement, the implants were restored with metal-ceramic fixed prostheses. Outcome measures were implant and prosthesis failure rates, complications, and peri-implant bone level changes at 1 year following delivery of the definitive prostheses. RESULTS: Two patients dropped out prior to the delivery of definitive prostheses. Four implants supporting a four-unit immediately loaded prosthesis failed in one patient, 3 months following delivery of the definitive prostheses. None of the conventionally loaded implants or prostheses failed. There were no significant differences in the proportions of implant and prosthesis failures (difference = 4.2%; 95% CI -4.2 to 12.6%; P = 0.999). In the immediately loaded group, four early prosthetic complications occurred during the provisionalization phase (three small resin chippings and one prosthetic screw loosening). No other complications were reported. The difference in the rate of complications between the two interventions was not statistically significant (difference = 16.7%; 95% CI -1.2% to 35.6%; P = 0.125). The 1-year peri-implant marginal bone level changes were evaluated in 23 patients (77 immediately loaded and 76 conventionally loaded implants). On average, patients lost 0.42 mm at the immediately loaded and 0.46 mm at the conventionally loaded implants, the difference being statistically not significant (difference = 0.044 mm; 95% CI -0.27 to 0.18 mm; P = 0.701). CONCLUSIONS: Immediate loading of 3- to 4-unit fixed partial prostheses supported by variable-thread implants in the posterior maxilla can yield good and similar 1-year results to one-stage conventionally loaded implants.

Sterilization and Biologic Monitoring in Private Dental Clinics in Lebanon.

AIM: The aim of the present study was to evaluate sterilization practices and effectiveness in the Lebanese private dental sector and identify potential factors contributing to sterilization failure. MATERIALS AND METHODS: A 13-item questionnaire consisting of four demographic/professional questions and nine questions related to sterilization practices along with self-contained biologic indicators (SCBIs) were delivered to a representative sample of Lebanese private offices. Univariate statistics and bivariate analyses were performed to compare sterilization failure rates according to demographic, professional, and sterilization-related conditions. RESULTS: Out of the 560 dentists contacted, 205 dentists returned the completed questionnaires and undamaged processed SCBIs. The tested autoclaves (n = 134) were mostly dynamic air removal (69.4%) and had a mean age of 10.5 ± 6.9 years. The dry heat ovens (n = 71) were all static air and had 12.9 ± 8.1 years. The dental assistants performed the routine sterilization procedures in nearly 62% of the practices and sterilization cycles were run 4 to 6 times per week in 75% of the offices. Correct temperature/time ratios were applied in 97% of the autoclaves and 80.3% of the ovens. Few dental practices reported having preventive maintenance (17.9% for the autoclaves and 14.1% for the ovens). Routine monitoring of sterilizer efficacy was infrequently performed and was mostly conducted using physical indicators. Sterilization failure rate was higher for the ovens (16.9%) than for the autoclaves (7.5%). Incorrect temperature/time ratio was the main significant factor associated with sterilization failures. CONCLUSION: The present study demonstrated a relatively high rate of sterilization failures in the Lebanese private dental sector and identified the human error in setting sterilization cycle parameters as the predominant cause of failure. These findings should prompt actions toward increasing knowledge of the sterilization processes and their monitoring among dental professionals and improving the quality control of sterilization through collaborative efforts among health authorities, dental schools, and associations. CLINICAL SIGNIFICANCE: This study presents the first published data relative to sterilization practices and effectiveness in private Lebanese dental offices and provides a rationale to implement biologic monitoring protocols in Lebanon as long practiced in developed countries.

Canal Straightening Following Overinstrumentation with Three Nickel-Titanium Rotary Instruments.

AIM: The aim of the present in vitro study to compare canal straightening following shaping of curved canals with three types of new generation nickel-titanium (NiTi) rotary instruments-ProTaper Next (PTN)®, BT RaCe (BTR)®, and WaveOne Gold (WOG)®- and three different levels of protrusion beyond the major apical foramen. MATERIALS AND METHODS: Forty-five extracted human maxillary and mandibular molars with at least one curved canal were distributed in three comparable groups of 15 canals each. The canals were instrumented to the major foramen and then overinstrumented with the final file 0.5 mm, 1 mm, and 1.5 mm beyond the foramen using PTN (Group PTN = 15), BTR (Group BTR = 15), and WOG (Group WOG = 15). Standardized pre- and post-instrumentation radiographs of the root canal were obtained for all groups using digital intraoral radiographs coupled with software. Differences in the degree of curvature were regarded as straightening and canal curvature was evaluated based on Schneider technique using the AmScope software for measurements and compared between groups and levels of instrumentation applying Mixed-model ANOVA. Significance was set at 0.05. RESULTS: Canal curvature tended to gradually straighten out as the level of instrumentation increased in all three groups without statistically significant difference among the groups (P = 0.826). CONCLUSION: Overinstrumentation in curved canals resulted in straightening of the canal curvature.

Marginal and internal fit of pressed lithium disilicate inlays fabricated with milling, 3D printing, and conventional technologies.

STATEMENT OF PROBLEM: The subtractive and additive computer-aided design and computer-aided manufacturing (CAD-CAM) of lithium disilicate partial coverage restorations is poorly documented. PURPOSE: The purpose of this in vitro study was to compare the marginal and internal fit accuracy of lithium disilicate glass-ceramic inlays fabricated with conventional, milled, and 3-dimensional (3D) printed wax patterns. MATERIAL AND METHODS: A dentoform mandibular first molar was prepared for a mesio-occlusal ceramic inlay. Five groups of 15 inlays were obtained through conventional impression and manual wax pattern (group CICW); conventional impression, laboratory scanning of the stone die, CAD-CAM milled wax blanks (group CIDW) or 3D printed wax patterns (group CI3DW); and scanning of the master preparation with intraoral scanner and CAD-CAM milled (group DSDW) or 3D printed wax patterns (group DS3DW). The same design was used to produce the wax patterns in the last 4 groups. The replica technique was used to measure marginal and internal adaptation by using stereomicroscopy. Mixed-model ANOVA was used to assess differences according to the groups and discrepancy location (α=.05). RESULTS: Group DSDW showed the smallest marginal discrepancy (24.3 µm) compared with those of groups CICW (45.1 µm), CIDW (33.7 µm), CI3DW (39.8 µm), and DS3DW (39.7 µm) (P<.001). No statistically significant differences were detected among groups CICW, CIDW, CI3DW, and DS3DW relative to the marginal discrepancy. The internal discrepancy was significantly larger than the marginal discrepancy within all groups (P<.001). CONCLUSIONS: Lithium disilicate glass-ceramic inlays produced from digital scans and subtractive milling of wax patterns resulted in better marginal and internal fit accuracy than either conventional impression/fabrication or additive 3D manufacturing. Three-dimensional printed wax patterns yielded fit values similar to those of the conventionally waxed inlays.

Relative Translucency of a Multilayered Ultratranslucent Zirconia Material.

AIM: The aim of this study was to compare the translucency parameter (TP) of ultratranslucent multilayered (UTML) zirconia according to thickness and layer level. MATERIALS AND METHODS: Rectangles of UTML zirconia with four layers [dentin layer (DEL), first transitional layer (FTL), second transitional layer (STL), and enamel layer (ENL)] and four different thicknesses (0.4, 0.6, 0.8, and 1 mm) were milled from blanks. Digital images were taken in a dark studio against white and black backgrounds under simulated daylight illumination and international commission on illumination (CIE) Lab* color values recorded using Photoshop Creative Cloud software. The TP was computed and compared according to thickness and layer level using analysis of variance (ANOVA) followed by Bonferroni post hoc analysis for multiple comparisons. Significance was set at p < 0.05. RESULTS: In each thickness, TP values were similar between any two layers. The significant effect of thickness on the TP was observed only in the first two layers. In the DEL, translucency was significantly greater at 0.4 mm than all other thicknesses. In the FTL, differences were significant between 0.4 and 0.8 mm and between 0.4 and 1 mm. CONCLUSION: The investigated zirconia does not seem to show gradational changes in relative translucency from dentin to enamel levels regardless of the thickness used. Thickness affected the TP only in the first two layers with better translu-cency at 0.4 mm. CLINICAL SIGNIFICANCE: Since relative translucency does not seem to be significantly different between layers, clinicians can modify the apicocoronal positioning of the UTML layers within the restoration according to the desired Chroma without any implications on the clinically perceived translucency. While the thickness of 0.4 mm may be suggested for anterior esthetic veneers because of its higher translucency, the other thicknesses of 0.6 to 1 mm can be used to mask colored abutments in full contour restorations.

Foramen Changes following Over Instrumentation of Curved Canals with Three Engine-Driven Instruments: An In Vitro Study.

INTRODUCTION: The present in vitro study aimed to evaluate and compare the changes in shape and surface area of the major foramen following shaping of curved canals with three new generation NiTi engine-driven instruments naming ProTaper Next, BT RaCe and WaveOne Gold- with 3 different levels of protrusion beyond the major apical foramen. METHODS AND MATERIALS: A total of 45 extracted human molars with at least one curved canal were distributed in 3 comparable groups of 15 that were instrumented using either ProTaper Next (PTN), BT RaCe (BTR) or WaveOne Gold (WOG). The canals were instrumented to the major foramen and then over instrumented with the final file 0.5 mm, 1 mm and 1.5 mm beyond the foramen. Standardized pre- and post-instrumentation photographs of the foramen were obtained for all groups using a stereomicroscope. Foramen shape and surface area were evaluated using the AmScope software for measurements and compared between groups and levels of instrumentation applying binary conditional logistic regression and repeated measures ANOVA. The level of significance was set at 0.05. RESULTS: Foramen shape tended to gradually change from circular to oval as the level of instrumentation increased in all groups. The original foramen shape in WOG group remained better than other groups. Foramen surface areas increased in all groups with Group BTR demonstrating significantly greater values than the other 2 groups. CONCLUSION: Over instrumentation resulted in apical enlargement and ovalization in all 3 groups but with different patterns. These differences can be attributed to the final file size, design characteristics and kinematics of the 3 systems.

Clinical and Patient-Centered Outcomes Following Treatment of Multiple Gingival Recessions Using Acellular Dermal Matrix Allografts.

The aim of this case series was to evaluate clinical and patient-centered outcomes when treating multiple recessions (Miller Class I, II, and III) affecting five or more teeth in a single procedure using acellular dermal matrix in 18 eligible participants (mean of 7.4 ± 1.7 recessions/patient). Low mean visual analog scale pain scores (0.7 ± 0.8) and analgesic consumption (2.3 ± 2.5 tablets) were reported from days 0 to 6 postoperatively. Mean baseline recession depth was 2.1 ± 1 mm. At 1 year postsurgery, mean percent root coverage was 87.1% ± 18.3%, and complete root coverage was achieved in 61.7% of recessions with statistically significant differences between smokers and nonsmokers.

CO2 Laser-Mediated Apically Positioned Flap in Areas Lacking Keratinized Gingiva.

BACKGROUND AND OBJECTIVES: Autogenous gingival grafts are considered the "gold standard" for gingival augmentation, however they require a second surgical site for graft harvesting. Apically positioned flaps (APFs) represent an alternative method in soft tissue augmentation procedures. Limited information is available relative to the effectiveness of laser-mediated APF in augmenting keratinized gingiva (KG). The aim of this paper is to evaluate soft tissues changes following APF using CO2 laser in mandibular incisors with minimal KG and high labial frenum attachment. MATERIALS AND METHODS: A total of 20 patients with minimal amount of KG (< 2 mm) on the labial aspect of one mandibular incisor and high buccal frenum insertion were selected for treatment. Only 19 completed the last follow-up visit. An APF consisting of a single superficial horizontal incision just coronal to the mucogingival junction using CO2 laser, elevation of a split-thickness flap, and suturing of the flap to the periosteum in an apical position was performed. The apico-coronal height of KG was measured at baseline, and at 3, 6 and 12 months postoperatively. RESULTS: Uneventful healing was observed in all patients and an increase in KG of 2-3 mm was obtained. Most patients rated the procedure and the postoperative course as non painful. CONCLUSIONS: CO2 laser-assisted APF procedure is a minimally invasive treatment modality associated with reduced risk of bleeding and predictable increase in the height of KG.

Could Salivary Cyclosporine Dosage Replace the Whole Blood Cyclosporine Measurements in Renal Transplant Patients?

BACKGROUND: Cyclosporin (CsA) has been extensively used as the immunosuppressant of choice in renal transplantation. Currently available approaches to assess CsA levels, both in serum and blood, fail to accurately reflect the concentration of the pharmacologically active drug fraction. Free CsA levels in biological fluids (blood or saliva) have been advocated to play an important role. Traditional salivary CsA monitoring tests are based on available archaic salivary techniques that are nonspecific and require large amounts of saliva. The aim of this study was to assess salivary CsA correlation using a novel and more accurate technique and to correlate with CsA levels in blood. MATERIAL AND METHODS: Patients provided blood samples of 2 ml and 2 ml of unstimulated saliva on the same day 2 h after the morning CsA dose (C2). Whole blood levels of CsA were determined using the monoclonal fluorescent polarization immunoassay (FPIA) kit. The FPIA kit was adapted to salivary testing by using a novel extraction method developed and patented under the name of Middle East Research Institute (MERI). Wilcoxon signed rank test compared the differences in blood and salivary CsA. Pearson's correlation coefficient assessed the linear association between blood and salivary CsA concentrations. All analyses were performed using IBM-SPSS version 23 (IBM Corp, Armonk, NY, USA). RESULTS: No significant correlation was observed between blood and salivary CsA levels. CONCLUSION: Salivary CsA concentrations at C2 cannot adequately replace C2 blood levels as an indicator of CsA bioavailability despite improved performance of monoclonal FPIA and application of the MERI technique. More studies may be warranted to design more reliable and less invasive procedures for therapeutic drug monitoring.

Infection Control Measures in Private Dental Clinics in Lebanon.

PURPOSE: Evaluate infection control knowledge, attitude, and practice in Lebanese private dental clinics. MATERIALS AND METHODS: A survey including 46 questions related to routine safety procedures was sent to 1150 Lebanese dentists between July 1st and 2nd, 2015. The study sample was selected from the database of registered dentists based on a proportional random sampling ensuring equitable representation of the 5 geographic regions of Lebanon. A subset of 29 questions was used to generate an overall score of compliance (excellent, good, fair, and poor). Comparisons according to gender, type, region, and years of practice were performed. RESULTS: 417 dentists returned the completed questionnaires. 96% expressed concern about infection transmission, 90.6% were vaccinated against Hepatitis B, and 61.8% asked routinely about patients medical history. Only 43% used protective eyewear. Although most dentists (65%) used autoclaves, dry heat was still used. Significant correlations were found between gender and use of personal protective equipment. Less compliance was shown by clinicians with fewer years of experience. In the overall compliance questionnaire, the mean percentage of correct answers was roughly 54% with <5% of the practitioners scoring "excellent." Conclusions. The study found inadequacy of compliance in private Lebanese dental clinics necessitating improved educational training and sustained monitoring by regulatory bodies.