Search

State of the art endodontic surgery with controlled retrograde procedures may not be feasible in all teeth due to poor access and other technical difficulties. In selected cases, the possibility to perform the sole apical resection without further retrograde manoeuvres might constitute a substantial clinical advantage. The present study compared the filling quality obtained with standard retrograde procedures with that of an alternative technique without retrograde preparation and filling. Methods: Previously published data served for sample size calculation (α=0.05; β=0.20; δ=3.0; σ=1.5). Twelve single-rooted teeth were selected from a pool of freshly extracted teeth, discarding those with aberrant anatomy. Selected teeth of comparable size were decoronated to obtain 12 mm long roots. The canals were scouted with manual files and the working length acquired. After mechanical glide path establishment, canal shaping was performed with HyFlex rotary files up to size 40, .04 taper (500 rpm; 2.5 Ncm). The roots were analysed with a computed microtomography scanner to identify the possible presence of dentine microcracks. Afterwards, all the canals were filled with the single cone technique with dedicated cones and BioRoot RCS bioceramic sealer. After 24 h, the roots were apically resected with a carbide bur 3 mm from the apex. At this point, the roots were randomly assigned to two groups: no retrograde procedures (n=6); standard retrograde ultrasonic preparation and Biodentine filling (n=6). Lastly, the formation of internal and external voids was quantified by means of a second computed microtomographic analysis. The normality of the distribution and the equality of variance of the microtomographic datasets were tested with a Shapiro-Wilk and a Levene test, respectively; then, the volumes measured in the two groups were statistically compared with an independent sample t-test (p=0.05). Results: Minimal voids volumes were observed in both considered groups. In the group entailing standard retrograde procedures, the mean voids volumes were 1.878±1.492 % of the entire canal space, in the group with sole root-end resection 0.823±0.576 %. The difference was not significant (p=0.137). Irrespective of the considered group, the small amounts of detected voids were mainly located inside the sealer. Conclusion: When executable, filling the canal with the single cone technique and bioceramic sealer associated with simple root-end resection appears to provide an effective seal of the endodontic space. In selected cases, such technique could make the need to perform retrograde preparation and filling less imperative.

Aim: To assess the influence of different motions on the cyclic fatigue resistance of Reciproc instruments simulating the temperature of the clinical conditions. Methods: The sample size was determined using statistical software set with the following parameters: α=0.05, β=0.20, δ=30.0, σ=28.0. The experiment required 54 Reciproc files. Brand new R25 files were randomly allocated to three groups defined by the tested motion: continuous rotation at 300 rpm (n=18), “RECIPROC” mode (n=18), and “WAVEONE” mode (n=18). The same endodontic motor was used for all groups (X-Smart IQ). All files were rotated/reciprocated until fracture inside a custom-designed artificial canal with 60° angle and 5-mm radius of curvature milled in a stainless-steel block. The testing device was electrically heated to keep its internal temperature at 35±1°C, which was constantly monitored with a thermometer. After file separation, the time to failure was registered with a digital chronometer and the length of the fractured fragment measured with a digital calliper. The fracture surface of each file was observed at the scanning electron microscope to perform a qualitative fractographic analysis. The collected data (time to fracture and fracture length) were tested for the normality of the distribution and the equality of variances with a Shapiro-Wilk and a Levene test, respectively. The dependent variables were compared amongst groups by means of a multivariate analysis of variance and Tuckey post-hoc test (p=0.05). Results: The continuous rotation group exhibited the shortest lifespan among the considered groups (85.4±9.5 s to failure). Both reciprocating motions were associated with a significant improvement of fatigue resistance (p

Aim To compare the filling quality obtained with standard retrograde procedures with that of a technique with the potential to simplify the surgical manoeuvres, namely the orthograde placement of 6 mm of mineral trioxide aggregate (MTA) followed by the root-end resection after cement setting. Methodology Sample size was calculated referring to previously published data (a = 0.05; b = 0.20; d = 3.0; r = 1.5). Accordingly, 12 freshly extracted single-rooted teeth were selected and transversally cut to obtain 12 mm long roots. Roots with aberrant anatomy were discarded. After manual scouting and mechanical glide path establishment, canals were shaped with HyFlex instruments up to size 40, 0.04 taper. The roots were randomly assigned to an experimental group (n = 6), where MTA was placed with a carrier and compacted with manual pluggers up to 6 mm from the working length, or to a control group that entailed filling with the single cone technique (n = 6). After 24 h, the roots in the experimental group received backfilling with thermoplasticised gutta-percha and apical resection. In the control group, the roots were resected apically and underwent standard retrograde ultrasonic preparation and MTA filling. The formation of internal and external voids was quantified by means of a computed microtomographic analysis. The normality of the distribution and the equality of variance of the datasets were tested; afterwards, the groups were compared statistically with an independent sample t-test (P = 0.05). Results Void formation was minimal in both experimental and control groups, ranging from 0.00% to 4.42% of the canal volume. In the control group, the voids (1.88 1.49%) were mainly external and related to sealer porosities. In the experimental group, the voids (1.08 0.50%) prevalently accumulated inside the MTA mass and at the interface between MTA and gutta-percha. The differences between the groups were not significant (P = 0.244). Conclusions The orthograde placement of MTA followed by apical resection may constitute a valid alternative to the standard surgical practice to simplify the surgical phases in selected cases.

Aim To evaluate the effect of different motions on the cyclic fatigue resistance of Reciproc Blue reciprocating files simulating the temperature of the clinical environment. Methodology After sample size calculation considering preliminary experimental data (a=0.05; b=0.20; d=30.0; r=32.0), 69 new R25 Reciproc Blue files were divided into three groups of 23 files each according to the tested motion: continuous rotation at 300 rpm, “RECIPROC” mode, and “WAVEONE” mode. All files were activated until fracture inside a stainless-steel artificial canal with 60° angle and 5 mm radius of curvature. The temperature was kept at 35°C and controlled with an internal thermometer inside the testing device. For each file, a single blinded operator measured the time to failure with a digital chronometer and the length of the fractured fragment with a digital calliper. A qualitative fractographic analysis was performed by observing the surface of the fractured files at the scanning electron microscope. The scalar data were tested for the assumptions for using parametric tests and then underwent a statistical analysis with a oneway analysis of variance and Tukey post hoc test (P = 0.05). Results The shortest lifespan of the files was registered in the continuous rotation group (204.1 24.2 s to failure). Both reciprocating motions led to significantly improved fatigue resistance. The “RECIPROC” mode performed better than the “WAVEONE” mode, exhibiting 329.8 31.5 s and 252.9 43.7 s to failure, respectively. No difference in fragment length was observed, confirming the correct positioning of the files inside the artificial canal. The scanning electron microscopic analysis confirmed that all the observed specimens fractured due to cyclic fatigue. Conclusions The results of the present study seem to encourage the use of R25 Reciproc Blue files preferably with their native motion to reduce the fracture risk in the clinical setting.

N/A

N/A

n/a

Aim To assess the effectiveness of two integrated shaping and filling techniques for the treatment of maxillary central incisors affected by chronic apical periodontitis. Methodology The trial enrolled 60 patients with a maxillary central incisors needing root canal treatment affected by chronic apical periodontitis with periapical radiolucency smaller than 5 mm in diameter. Block-randomization was undertaken to allocate the patients to two treatment groups with different canal shaping and filling protocols: group 1 (G1, n = 30), Revo-S/One Step Obturator; group 2 (G2, n = 30) GTX/GTX Obturator. An independent examiner evaluated the patients at baseline, after 6, 12, 24 and 36 months by performing percussion and palpation tests. At the same time points, standardized periapical radiographs were taken to score the radiographic healing according to a previously published scale. For this analysis, the level of agreement with regard to the scores assigned by two blind evaluators was tested by weighted kappa statistics. Comparability of baseline clinical data, as well as the differences between the two groups and among time points concerning clinical and radiographic data were evaluated with non-parametric tests (p < 0.05). Results All the patients were re-evaluated after 3 years. One patient per group complained of mild symptoms at the end of the observation period. Radiographic healing was progressive during the follow-up. The lesions were classified as totally healed, partially healed and not healed in 93.3%, 3.3% and 3.3% of cases in G1 and in 93.3%, 0% and 6.7% of cases in G2. The differences between groups were not significant (p > 0.05). Conclusions The two integrated endodontic systems were equally effective in achieving high three-year success rates in the treatment of maxillary central incisors with chronic apical periodontitis.

Aim To evaluate the fit against root canal walls obtained with a single-taper post system, placed without further canal enlargement, and a double-taper post system requiring traditional post space preparation with burs. Methodology Twenty straight single-rooted teeth were cut to obtain 14 mm-long roots. Canals were shaped with Mtwo rotary files up to size 40, 04 taper and filled with the continuous wave of condensation technique, leaving an unfilled coronal space of 9 mm. Ten roots were randomly assigned to group 1 (G1) and received a SurgiPost Multiconical single-tapered post, which had previously undergone standardised trimming. In the remaining roots (G2), the post space was prepared with the bur of the DT Light-post system to place a double-taper post of corresponding size. The posts were luted with RelyX self-adhesive cement. Cement thickness was measured on sectioned specimens at the scanning electron microscope (120 readings per post third). Parametric statistical tests were used to compare the cement thickness between the two groups and among post thirds (a = 0.05). Results At the coronal level, cement thickness was minimum and similar in the two groups. The effects of drilling were visible on the canal walls on the apical third of the post in G1, which was characterized by even cement distribution irrespective of the post third. The cement thickness was limited also in G2, but slightly increased at the post tip (p < 0.05). Conclusions The post systems achieved satisfactory fit in straight single-rooted teeth in the coronal and middle post thirds. At the tip of the post, the post space preparation with drills allowed for excellent fit but required further removal of dentine, while single-taper posts provided an inferior fit at this level due to the standardised methodology needed in the research setting.

SUMMARY This article describes the case of a vital molar tooth with a vast furcal iatrogenic root perforation and biologic width violation, which was successfully managed by a multidisciplinary approach aimed at preserving pulp vitality. The root perforation was cleaned and then sealed with mineral trioxide aggregate, which was positioned onto the pulp at the canal orifices. After one month, the patient was not reporting symptoms, and the tooth was positively responding to the thermal test. The tooth was orthodontically extruded, subjected to minimally invasive crown lengthening, and prepared to receive a full-crown restoration. Radiotransparent composite resin was chosen as a permanent restorative material to better monitor possible endodontic complications at the coronal level. The patient's tooth was followed up for eight years uneventfully. The present case is an example of the possibility to subject a root-repaired tooth with fully formed apices to conservative yet complex multidisciplinary treatment while maintaining pulp vitality.

Acute or strenuous exercise is sometimes related to upper respiratory tract infections in athletes. Practicing intense and regular exercise can lead to incorrect activation of the immune system, causing athletes to be excluded from training programs and competitions. Defensins are small antimicrobial peptides that are part of the innate immune system and dynamically involved in several biological activities. In this study, we highlight the role of human defensins in competitive basketball athletes. In particular, we consider the behavior of alpha- and beta-defensins together with white blood cells in a cohort of players. Moreover, we focus our attention on cortisol, a physiological indicator of stress, and testosterone, both of which are human hormones involved in muscle metabolism. The free-testosterone/cortisol ratio is considered to be an indicator of overtraining among athletes. This paper provides an up-to-date information of the role of human defensins as self-defense molecules during a continuous stressor such as long-term exercise, and it recognizes them as potential markers of infection.

The first studies on Staphylococcus aureus (SA) infections in athletes were conducted in the 1980s, and examined athletes that perform in close physical contact, with particular attention to damaged or infected skin. Recent studies have used molecular epidemiology to shed light on the transmission of SA in professional athletes. These studies have shown that contact between athletes is prolonged and constant, and that these factors influence the appearance of infections caused by SA. These results support the need to use sanitary measures designed to prevent the appearance of SA infections. The factors triggering the establishment of SA within professional sports groups are the nasal colonization of SA, contact between athletes and sweating. Hence, there is a need to use the most modern molecular typing methods to evaluate the appearance of cutaneous SA disease. This review aims to summarize both the current SA infections known in athletes and the diagnostic methods employed for recognition, pointing to possible preventive strategies and the factors that can act as a springboard for the appearance of SA and subsequent transmission between athletes.

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. [Figure not available: see fulltext.].

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. [Figure not available: see fulltext.]

Staphylococcus aureus is a microorganism capable of causing numerous diseases of the human skin. The incidence of S. aureus skin infections reflects the conflict between the host skin′s immune defenses and the S. aureus’ virulence elements. Antimicrobial peptides (AMPs) are small protein molecules involved in numerous biological activities, playing a very important role in the innate immunity. They constitute the defense of the host′s skin, which prevents harmful microorganisms from entering the epithelial barrier, including S. aureus. However, S. aureus uses ambiguous mechanisms against host defenses by promoting colonization and skin infections. Our review aims to provide a reference collection on host–pathogen interactions in skin disorders, including S. aureus infections and its resistance to methicillin (MRSA). In addition to these, we discuss the involvement of defensins and other innate immunity mediators (i.e., toll receptors, interleukin-1, and interleukin-17), involved in the defense of the host against the skin disorders caused by S. aureus, and then focus on the evasion mechanisms developed by the pathogenic microorganism under analysis. This review provides the “state of the art” on molecular mechanisms underlying S. aureus skin infection and the pharmacological potential of AMPs as a new therapeutic strategy, in order to define alternative directions in the fight against cutaneous disease.

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.

Aim: The use of all-ceramic conservative occlusal veneers is becoming more popular in the clinical setting thanks to the recent improvement of the mechanical and esthetical properties of the restorative materials. Furthermore, the option of CAD/CAM fabrication may constitute a further advantage for both clinicians and patients. Since little is known about the influence of the occlusal veneer preparation design on the marginal fit of the final restoration, the present study compared the marginal fit of two preparation designs. Methods: Sixteen maxillary molars were selected from a pool of freshly extracted teeth and received 1-mm cusp reduction by using silicon indexes as reference. The teeth were randomly divided into two groups identified by the preparation design: conservative full-coverage occlusal veneer with a 90° rounded shoulder margin (n=8) and marginal chamfer (n=8). At the end of the preparation process, the exposed dentine surfaces were immediately sealed with a self etch adhesive system. Lithium disilicate restorations (IPS e.max CAD) were produced with the Cerec 3 CAD/CAM system. The intaglio surface of the occlusal veneers was conditioned with hydrofluoric acid and silane, while the tooth surface underwent silicatization, enamel etching, and adhesive system application. The occlusal veneers were luted with Variolink II cement. The specimens were embedded into acrylic resin simulating the periodontal ligament with a layer of vinyl polysiloxane; then, they were chewing machine (1,250,000 cycles, 1 Hz, 5-55°C). A quantitative marginal fit evaluation was performed observing at the scanning electron microscope resin replicas of the specimens obtained before and after the thermomechanical aging simulation. For each replica, a single trained blinded operator measured the marginal gap along 120 equidistant points of the adhesive interface. Collected data were tested for the assumptions for using parametric tests. The marginal fit measured at different experimental time points was compared within the same group with a paired sample t-test, while the two groups were compared at the same time point with an independent-sample t-test (p

Aim: To evaluate the resistance to load of maxillary molars restored with composite overlays manufactured with three different techniques, namely the traditional indirect technique, a chairside semi-direct technique, and a CAD/CAM technique. Methods: Sample size was calculated considering the results obtained in preliminary experimental studies (α=0.05; β=0.20; δ =500.0; σ =300.0). Eighteen sound maxillary molars of comparable size were selected from a pool of freshly extracted teeth and received a standardized preparation for a full-coverage overlay with two proximal boxes. The prepared teeth were randomly divided into three experimental groups of 8 elements each: traditional indirect technique with polyvinyl siloxane impression and stratification on a stone model; chairside semi-direct technique with alginate impression and stratification on a silicon model; CAD/CAM technique with digital impression and production with the Cerec 3 system. All tested materials were resin-based composites of the same brand (Voco). For the CAD/CAM production process, a custom-designed phantom model was used. The cementation protocol was the same for all groups and involved the use of sandblasting, self-etch adhesive procedures with selective enamel etching, and dual cure resin cement. All the restored teeth underwent thermomechanical aging (1,250,000 cycles, 1Hz, 5-55°C); afterwards, they were axially loaded to fracture with a universal testing machine with a round-head stainless steel stylus. The type of fracture was registered. The groups were compared in terms of maximum load to fracture with a one-way analysis of variance and Scheffè post-hoc test (p

Aim: Manufacturers aim at improving filler technology to enhance the properties of the restorative materials, thus maximising the aesthetic and functional outcome of the restored tooth. The present study tested the degree of conversion (DC), rate of cure (RC), microhardness (VHN), depth of cure (VHR) and contraction stress (CS) of three new nano hybrid composites with pre-polymerized spherical filler. Methods: Three commercially available composite resin were characterised in the present study, namely the Ceram.X® universal shade A3 (CXUA3), Ceram.X® duo enamel shade E2, and Ceram.X® duo dentin shade D3 (CXDE2 and CXDD3). The materials were light-cured with a LED light (SmartLite Focus, measured output 1301 mW/cm2) following the protocol recommended by the manufacturer. DC was assessed by means of Fourier-transform infrared spectroscopy, calculating RC from a second-grade polynomial fitting of the kinetic curve. A microhardness testing machine equipped with a Vickers indenter served to measure the top and bottom VHN of 2 mm-high disc-shaped specimens, using the bottom/top surface values ratio (VHR) as indirect evaluation of the depth of cure. CS vs time was evaluated by a universal testing machine provided with an extensometer as feedback system, CS was normalized for the specimen bonding area. All data sets underwent statistical analysis with dedicated software and tested for the assumptions for the use of parametric tests. Multiple analyses of variance with Scheffé post hoc test were carried out to compare the dependent variables of interest among the tested materials. Results: All tested materials exhibited a DC lower than 50%, with CXUA3 reaching the lowest DC value after 10 s. RC of CXUA3 at 5 s was comparable to that of CXDE2, while after 10s RC of CXUA3 decreased to a value proportional to that of CXDD3. For all the tested materials, top-VHN was greater than bottom-VHN. Top-VHN of CXDE2 was lower than CXUA3 and CXDD3. CXDD3 was the only material achieving VHR>80%. The main differences in CS among the tested materials were found during the irradiation with curing-light: CXDE2 displaying the lowest CS after 10 s and CXDD3 the highest after 30 s. Conclusion: The present study proved that the light curing protocol suggested by the manufacturer for the three composites might be improved: 10 s of irradiation seemed insufficient to adequately cure CXUA3 and CXDE2. Longer curing times for these materials appear advisable.

Aim To evaluate the resistance to load of composite and lithium silicate CAD/CAM endocrowns cemented on maxillary molars with or without margin relocation in a standardised proximal box. Methodology Sample size was calculated making reference to the results of a preliminary study (a=0.05; b=0.20; d=500.0; r=280.0). Thirty-two intact extracted maxillary molars of comparable size were root-filled and randomly allocated to four experimental groups (n = 8): composite endocrown without margin relocation; composite endocrown with margin relocation; lithium silicate without margin relocation; lithium silicate with margin relocation. The tested CAD/CAM materials were Lava Ultimate and Celtra DUO for composite and lithium silicate groups, respectively. The margin relocation procedure involved the preparation of a standardized mesial box and restoration with a flowable composite. The endocrowns were obtained with the Cerec 3 CAD/CAM system making use of a custom-designed phantom model and luted with self-adhesive cement. The restored teeth underwent thermomechanical aging (1 250 000 cycles, 1 Hz, 5–55°C) and were axially loaded to fracture with a universal testing machine. Fracture types were qualitatively assessed. Maximum load to fracture were compared amongst groups with a two-way analysis of variance and Duncan post hoc test (P < 0.05). Results No specimens exhibited appreciable defects after the thermomechanical aging. The mean maximum load values exceeded the threshold of the masticatory forces in all the tested groups. The composite endocrown without margin relocation obtained the greatest resistance values (1910.6 373.1 N), while the lithium silicate with margin relocation obtained the lowest (1314.9 326.1 N). For both tested materials, margin relocation slightly but not significantly reduced the resistance values. Most specimens had non-restorable fractures. Conclusions Under the conditions of the present study, margin relocation did not influence the resistance to fracture of teeth restored with CAD/CAM endocrowns. A trend of improved resistance to load of endocrown restorations was observed for the tested composite material in comparison to lithium silicate.

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.

SUMMARYThis systematic review was carried out to assess the clinical effectiveness of nanofilled and nanohybrid composites used for direct restorations in comparison with microhybrid composites. The guidelines for the preferred reporting items for systematic reviews and meta-analyses were followed. A search of articles published from July 1996 to February 2017 was performed in PubMed, SciVerse Scopus, Latin American and Caribbean Health Sciences, the Scientific Electronic Library Online, and the Cochrane Library. The present review selected only randomized controlled trials comparing the clinical performance of a nanofilled or nanohybrid composite for direct restorations with that of a microhybrid composite. The research found 201 studies. Twenty-one articles fulfilled the criteria of the present review. However, the included studies were characterized by great methodological diversities. As a general trend, nanofilled and nanohybrid composites were found to be capable of clinical performance, marginal quality, and resistance to wear similar to that of traditional composites without showing improved surface characteristics. The risk of bias of included studies was judged unclear or high. The clinical performance of nanofilled/nanohybrid composites was found to be comparable to that of traditional composites in the posterior area. The data concerning anterior and cervical restorations were insufficient. With regard to the esthetic properties, there is a compelling need for studies on anterior teeth in which the operators are kept unaware of the restorative material. Nanofilled/nanohybrid composites seem to be a valid alternative to traditional microhybrid composites, and at the moment, there is low-level evidence attesting a lack of their superiority.

N/A

Aim. The aim of the present microleakage study was to assess the sealing ability of nanohybrid composite crowns with different finish lines exposed to simulated mechanical periodontal treatment (SMPT). Methods. After sample size calculation (α=0.05; β=0.20; δ=1.0; σ=0.8), sixty extracted mandibular molars were divided into four groups (N.=15): G1, 90° shoulder; G2, beveled 90° shoulder; G3, 90° shoulder and SMPT; G4, beveled 90° shoulder and SMPT. Tooth preparations were carried out by means of diamond burs and Arkansas stones. The buildup of crowns was performed with a nanohybrid composite on master casts obtained after polyether impressions and crowns were cemented with self-adhesive cement. Groups G3 and G4 were subjected to the equivalent of five years of semestral mechanical periodontal scaling with Gracey curettes (2-mm long strokes, 5 N). Samples were immersed into a methylene blue supersaturated solution for 10 minutes. Microleakage was measured by stereomicroscopic observation of multiple sections of the samples and leakage data underwent statistical analysis with non-parametric tests. Results. Marginal microleakage was 1.53±1.27% and 17.60±12.72% of the length of the adhesive interface in G1 and G2, respectively. SMPT reduced dye penetration (P