Root-end resection with or without retrograde obturation after orthograde filling with two techniques: A micro-CT study.

To evaluate the filling ability of two orthograde obturation techniques followed by the apical resection with or without retrograde obturation through micro-computed tomography (CT). Thirty-two single-rooted permanent teeth were prepared and randomised into four groups (n = 8) according to the orthograde obturation technique (single cone technique [SCT] and mineral trioxide aggregate placement) combined or not with retrograde obturation. The volume of voids (VoV) within the entire endodontic space, the apical 3 mm, and 1 mm after root resection was calculated by micro-CT. Statistical analysis showed no significant difference among the groups regarding the total VoV in all root canals, as well as within the apical 1 mm after root resection. The SCT and apical resection without retrograde filling showed significantly better results in terms of VoV at the apical 3 mm after root resection. Within the study limitations, SCT associated with apical resection without retrograde preparation exhibited a similar or less amount of voids than the other groups.

Retreatability of calcium silicate-based root canal sealer using reciprocating instrumentation with different irrigation activation techniques in single-rooted canals.

This study analysed the bioceramic sealer cleaning ability of two chemo-mechanical systems in intact and restored teeth. Thirty-two single-rooted teeth were used, and half of them restored with a pre-endodontic composite restoration (PCR). All samples were instrumented with a size 40 Reciproc Blue file and filled with BioRoot RCS. Canals were retreated using the R40 and then R50 Reciproc Blue. The samples were divided into four experimental groups (n = 8): intact teeth/passive ultrasonic irrigation (PUI) (G1), intact teeth/shock wave-enhanced emission photoacoustic streaming (SWEEPS) (G2), PCR/PUI (G3) and PCR/SWEEPS (G4). The samples were scanned by micro-CT before and after retreatment, and the volume of remaining filling material was evaluated. The minor percentage of residues were observed in G2, with a volume of 0.447 ± 0.356% of the endodontic space (P < 0.001). The Reciproc/SWEEPS technique showed the better performance in intact teeth compared with PUI technique. Pre-endodontic restoration did not significantly affect the effectiveness of sealer removal.

Influence of Thickness and Shade on the Color of Layered Novel Nanohybrid Composite Systems.

The influence of the layer thickness and composite shade on the final color of Ceram.X composites (Dentsply Sirona) was tested, selecting five intermediate-translucency Ceram.X Universal shades, three high-translucency Ceram.X Duo "enamel" shades, and four low-translucency Ceram.X Duo "dentin" shades. Using cylindrical molds, 850 specimens were obtained, representing the whole array of possible Universal single specimens (in seven thicknesses, ranging from 1.0 to 4.0 mm in 0.5-mm increments) and Duo combinations. The CIELAB coordinates of each specimen were determined with a spectrophotometer. Different thicknesses and composites were compared with Clark's ΔE. The difference in color among specimens of different thicknesses was material-dependent. The thickness and shade of the composite markedly affected the color yield of the Ceram.X system. For each shade of the Universal systems, only one Duo enamel-dentin combination corresponded.

Surgical extrusion: A dental technique.

This article describes a technique for surgically extruding severely compromised roots needing prosthetic rehabilitation. Unlike previously described approaches, the technique does not require advanced clinical skills or equipment, may reduce the risk of tooth or bone fracture during the luxation maneuvers, and does not seem to interfere with the alveolar socket healing process.

Evaluation of degree of conversion, rate of cure, microhardness, depth of cure, and contraction stress of new nanohybrid composites containing pre-polymerized spherical filler.

The aim of the present study was to characterize nanohybrid and nanofilled composites in terms of degree of conversion (DC), rate of cure (RC), microhardness (Vickers hardness number; VHN), depth of cure, and contraction stress (CS). Ceram.X® universal- A3, duo enamel E2, and duo dentin D3 composites were compared to Tetric EvoCeram® and FiltekTMSupreme XTE composites of equivalent dentin and enamel shades under a 40 s photopolymerization protocol. DC was measured by infrared spectroscopy, calculating RC from the kinetic curve. Top and bottom VHN were determined using a Vickers indenter, and bottom/top surface ratio (Vickers hardness ratio; VHR) calculated. CS vs. time was assessed by a universal testing machine and normalized for the specimen bonding area. All materials showed DC < 60%, Ceram.X® composites reaching higher values than the other composites of corresponding shades. RC at 5 s of photopolymerization was always higher than that at 10 s. All the Ceram.X® composites and the lighter-shaded Tetric EvoCeram® and FiltekTMSupreme XTE composites reached the RC plateau after 25 s, the remaining materials showed a slower kinetic trend. Tetric EvoCeram® and FiltekTMSupreme XTE composites displayed the softest and the hardest surfaces, respectively. Differently from darker-shaded materials, the universal and the three enamel-shaded composites resulted optimally cured (VHR > 80%). The tested composites differed in CS both during and after light cure, Tetric EvoCeram® and FiltekTMSupreme XTE composites displaying the highest and the lowest CS, respectively. Only the Ceram.X® universal-A3 reached a CS plateau value. The tested composites exhibited material-dependent chemo-mechanical properties. Increasing the curing time and/or reducing the composite layer thickness for dentin-shaded composites appears advisable.

Filling ability of three variants of the single-cone technique with bioceramic sealer: a micro-computed tomography study.

The present study evaluated the quality of single-cone root canal fillings with bioceramic (BC) sealer using three different techniques by means of micro-computed tomography (micro-CT). The canals of 30 extracted single-rooted permanent teeth were shaped with R40 Reciproc blue files and filled with the single-cone technique (SCT). BioRoot RCS BC sealer was placed inside the canals with one of the following master cones: R40 cone to working length (RWL, n = 10); R40 cone trimmed 1 mm short of working length (RWL-1, n = 10); non-standardized gutta-percha cone to working length (NSWL, n = 10). A quantitative and qualitative micro-CT analysis assessed the filling quality and internal/external voids formation. Collected data underwent statistical analysis by multivariate one-way analysis of variance (α = 0.05). In all groups, the voids were minimal and prevalently external. The NSWL and RWL-1 groups had increased sealer ratios in the whole canal and the apical canal portion, respectively. The lowest amounts of voids were found in the RWL group; the void volumes were slightly greater in the RWL-1 mm and NSWL groups, especially at the apical level. Two alternative SCTs showed satisfactory filling ability, uniform distribution of the BC sealer, and a minimally increased voids formation compared to the standard SCT with dedicated cone. The two tested alternative SCTs could take advantage of the beneficial characteristics of the BC sealer, which evenly filled the endodontic space, ideally sealing both the major and the accessory communications with the periodontium.

Outcome of Different Surgical Approaches in the Treatment of Class II Furcation Defects in Mandibular Molars: A Randomized Clinical Trial.

The aim of this study was to investigate which factors play a major role in the healing of Class II mandibular furcation defects treated with different surgical techniques. Twenty-five systemically healthy subjects with periodontitis stage III grade B and Class II buccal mandibular furcation involvement received one of the following open flap debridement approaches: Group 1 (n = 10), no further treatment; Group 2 (n = 10), piezoelectric contouring of the furcation roof; Group 3 (n = 9), piezoelectric contouring of the furcation roof and bone grafting; Group 4 (n = 10), piezoelectric contouring of the furcation roof and bone grafting with coronally positioned flap. Clinical and radiologic variables-bleeding on probing, probing depth (PPD), vertical and horizontal bone level (CAL and PH), gingival recession, root trunk length, radicular separation, and furcation perimeter (FP)-were evaluated at baseline and 180 days and 1 year after surgery. All clinical parameters were statistically analyzed. Surgical techniques caused clinical (CAL, PPD, PH) and radiographic (FP) improvements. Regenerative techniques and the coronally positioned flap yielded a major radiographic reduction of furcation areas. All therapies resulted in significant horizontal and vertical PPD reduction and CAL gain.

Primary Stability of Short Implants Inserted Using Piezoelectric or Drilling Systems: An In Vitro Comparison.

The primary objective of the present in vitro study was to evaluate the influence of implant site preparation technique (drills vs ultrasonic instrumentation) on the primary stability of short dental implants with two different designs inserted in simulated low-quality cancellous bone. Eighty implant sites were prepared in custom-made solid rigid polyurethane blocks with two different low cancellous bone densities (5 or 15 pounds per cubic foot [PCF]), equally distributed between piezoelectric (Surgysonic Moto, Esacrom, Italy) and conventional drilling techniques. Two short implant systems (Prama and Syra, Sweden & Martina) were tested by inserting 40 fixtures of each system (both 6.0 mm length and 5.0 mm diameter), divided in the four subgroups (drills/5 PCF density; drills/15 PCF density; piezo/5 PCF density; piezo/15 PCF density). Insertion torque (Ncm), implant stability quotient values, removal torque (Ncm), and surgical time were recorded. Data were analyzed by 3-way ANOVA and Scheffé's test (α = 0.05). With slight variations among the considered dependent variables, overall high primary implant stability was observed across all subgroups. Piezoelectric instrumentation allowed for comparable or slightly superior primary stability in comparison with the drilling procedures in both implant systems. The Prama implants group showed the highest mean reverse torque and Syra implants the highest implant stability quotient values. Piezoelectric implant site preparation took prolonged operative time compared to conventional preparation with drills; among the drilling procedures, Syra system required fewer surgical steps and shorter operative time.

Influence of preparation designs on marginal adaptation and failure load of full-coverage occlusal veneers after thermomechanical aging simulation.

OBJECTIVES: To evaluate the fracture resistance and marginal quality of maxillary molars restored using lithium disilicate glass-ceramic (LDG) occlusal veneers with two preparation designs. METHODS: Sixteen extracted maxillary molars were assigned to two groups (n = 8). In group 1 (G1), the teeth received a preparation for a conservative full-coverage occlusal veneer restoration with a 90° rounded shoulder margin. In group 2 (G2), the teeth underwent a 1-mm cusp reduction with a marginal chamfer. LDG restorations (IPS e.max CAD) were obtained with the Cerec 3 CAD/CAM system and luted with Variolink II cement. After thermomechanical aging (1 250 000 cycles), the specimens were loaded to fracture. A semiquantitative marginal seal evaluation was performed observing resin replicas of the specimens at the scanning electron microscope. Cement thickness was assessed at the stereomicroscope on sectioned specimens. Collected data were statistically analyzed by parametric and nonparametric tests. RESULTS: The maximum load to fracture was 2395.01 ± 150.96 N in G1 and 2408.39 ± 112.66 N in G2. Most of the observed specimens exhibited restorable fractures and continuous margins. Cement thickness was 132 ± 38 µm in G1 and 150 ± 41 µm in G2. No differences between the groups emerged. CONCLUSION: This study demonstrated similar satisfactory performance of the two considered preparations designs for occlusal veneer with LDG. CLINICAL SIGNIFICANCE: A new minimally invasive occlusal veneer preparation with marginal chamfer exhibited promising fracture resistance and marginal adaptation that were comparable to those of a standard conservative preparation for the restoration of molars with CAD/CAM lithium disilicate occlusal veneers.

In vitro comparison of cyclic fatigue resistance of two rotary single-file endodontic systems: OneCurve versus OneShape.

The aim of the present study was to evaluate the difference in cyclic fatigue resistance between OneCurve (OC) and OneShape (OS) endodontic single-file NiTi systems in a severely curved artificial canal. After sample size calculation (α = 0.01; ß = 0.20; σ = 20.0; δ = 20.0), 25 OC and 25 OS files were used. An artificial canal with 60° angle and 5-mm radius of curvature was milled in a stainless-steel block reproducing the size and taper of the files used. The test device was electrically heated to maintain the environmental temperature at 37 °C. All files were rotated until fracture; the time to failure was recorded and the number of cycles to fracture (NCF) calculated. The length of the fractured fragments was measured too. Fractographic examination and cross-sectional area calculation were performed by scanning electron microscopy analysis (SEM). Data were statistically analyzed using an independent sample t test. The significance level was set at 0.01. Statistical analysis showed that OC files exhibited significantly greater cyclic fatigue resistance than OS (p < 0.001), with 721 ± 89 NCF and 301 ± 38 NCF, respectively. No significant difference was found in the length of the fractured fragments (p > 0.01). SEM fractographic analysis confirmed that all the scanned samples separated due to cyclic fatigue. Within the limitations of the present study, OC endodontic instruments resisted to cyclic fatigue better than OS. The improved mechanical resistance of OC could be related to new NiTi alloy used for their manufacturing.

Computed microtomography study of untreated, shaped and filled mesiobuccal canals of maxillary first molars.

This study assessed the effectiveness of modern endodontic shaping and filling procedures on mesiobuccal roots of maxillary molars with two canals. The canals of 20 mesiobuccal roots were treated with Mtwo rotary files, passive ultrasonic irrigation and Guttafusion obturators. X-ray computed microtomography analysis was carried out prior to treatment, after canal shaping and after canal filling to determine the alterations of the canal volume before and after the instrumentation, the volume of the hard tissue debris, and percentage of the volume occupied by filling materials. The shaping instruments and filling materials reached only partially the endodontic space of the second mesiobuccal canal and the accessory endodontic structures. Canal irregularities, ramifications, and interconnections were accumulation sites of hard tissue debris. This study demonstrated that rotary files, passive ultrasonic irrigation and carrier-based filling systems could be partially effective for the treatment of the mesiobuccal canals and their accessory endodontic structures.

The effectiveness of surgical management of oroantral communications: a systematic review of the literature.

BACKGROUND: An oroantral communication (OAC) is a common complication in alveolar surgery that usually occurs as a result of the extraction of maxillary posterior teeth. To avoid further complications, several closure techniques are used; most of them need a flap elevation. Recently, simpler conservative flapless techniques for OAC closure have been described. OBJECTIVES: To appraise the effectiveness of different techniques for closure of OACs also in comparison to nothing. SEARCH METHODS: The following electronic databases were searched for randomised controlled trials regarding techniques for closure of OACs: PubMed; SciVerse Scopus; Latin American and Caribbean Health Sciences; The Scientific Electronic Library Online and The Cochrane Library (from January 1949 to August 2014). Unspecific algorithms were chosen in order to maximise search sensibility. Additional manual searching was performed in PubMed related citations, in five journals and in the references of the selected articles. There were no restrictions with regard to publication language. SELECTION CRITERIA: Randomised controlled trials (RCTs) comparing techniques for closing oroantral communications to nothing, or different techniques for closing oroantral communications reporting the success rate with at least two months follow-up. DATA COLLECTION AND ANALYSIS: The screening of eligible studies, the assessment of methodological quality and data extraction were done by two independent reviewers working in duplicate. RESULTS: The research individuated 1256 publications. After screening, only five articles were assessed for eligibility. Only two RCTs evaluating the effectiveness of techniques for OAC closure fulfilled the inclusion criteria of the present review. One trial including 30 patients assessed whether flapless techniques (resorbable root analogues and haemostatic gauze) could be as effective as the Rehrmann's buccal flap; all the patients were reported as successfully healed in the three intervention groups. Another RCT with 20 patients compared the effectiveness of the buccal fat pad flap (100% success rate) with a sandwich graft with hydroxyapatite crystals within collagen sheaths (90% success rate). The authors found no significant difference. CONCLUSIONS: There are no RCTs evaluating whether an oroantral communication should be closed or not. There is weak evidence from two RCTs showing good results with five different techniques for closure of OACs (resorbable root analogues, haemostatic gauze, Rehrmann's buccal flap, buccal fat pad flap, sandwich graft with hydroxyapatite crystals). Until sufficiently high quality RCTs are conducted, elevating or not a flap for closure of OACs will be left to the personal choice of the surgeon.

Analysis of single point and continuous wave of condensation root filling techniques by micro-computed tomography.

The aim of the present microtomographic study was to investigate the quality of root canal filling and the voids formation in canals of extracted teeth instrumented with a simultaneous technique and filled with two different methods. Twenty-four single-rooted teeth were assigned to two experimental groups (no. = 12); canals were shaped with NiTi rotary files, irrigated with NaOCl and filled either with the single point (group 1) or the continuous wave of condensation technique (group 2). Specimens underwent microtomographic scanning. Collected data were statistically analyzed by nonparametric methods. Void mean percentages were found to be limited and similar between the two groups; the single point technique led to greater sealer thickness in partially oval canals.