Glide path enlargement of curved molar canals using HyFlex EDM glide path file versus PathFile: a comparative study of preparation time and postoperative pain.

BACKGROUND: This randomized clinical trial aimed to compare the preparation time and severity of postoperative pain between HyFlex Electric Discharge Machine (EDM) glide path file (GPF) and PathFile. METHODS: Eighty patients whose molar teeth had at least one severely curved canal were treated by the same specialist. After access cavity preparation, the patients were randomly assigned to receive glide path enlargement with either HyFlex EDM GPF or PathFile. ProTaper Next X1 and X2 files were used to prepare the canals. The time of preparation was assessed and the severity of postoperative pain over the next 7 days was recorded. The preparation time and the postoperative pain scores were compared using the Linear Mixed Models (P ≤ 0.05). RESULTS: Glide path enlargement time was significantly shorter with HyFlex EDM GPF (27.828 ± 2.345 s) than with PathFile (48.942 ± 2.864 s) (P < 0.001). The highest postoperative pain score was recorded on the first day and the pain decreased over time in both groups. HyFlex EDM GPF group patients reported significantly less postoperative pain than PathFile group patients overall (P < 0.001). CONCLUSIONS: Postoperative pain and glide path preparation time could be reduced by using HyFlex EDM GPF system. Trial registration PKUSSNCT, PKUSSNCT-17B12, Registered 24 October 2017.

Post endodontic pain following single-visit root canal preparation with rotary vs reciprocating instruments: a meta-analysis of randomized clinical trials.

BACKGROUND: In endodontic therapy, continuous rotary instrumentation reduced debris compared to reciprocal instrumentation, which might affect the incidence of post-endodontic pain (PP). The aim of our study was to assess whether PP incidence and levels were influenced by the choice of rotary or reciprocal instruments. METHODS: In this meta-analysis the Pubmed and EM databases were searched for prospective clinical randomized trials published before April 20, 2016, using combinations of the keywords: root canal preparation/instrumentation/treatment/therapy; post-operative/endodontic pain; reciprocal and rotary instruments. RESULTS: Three studies were included, involving a total of 1,317 patients, 659 treated with reciprocating instruments and 658 treated with rotary instruments. PP was reported in 139 patients in the reciprocating group and 172 in the rotary group. The PP incidence odds ratio was 1.27 with 95% confidence interval (CI) (0.25, 6.52) favoring rotary instruments. The mild, moderate and severe PP levels odds ratios were 0.31 (0.11, 0.84), 2.24 (0.66, 7.59) and 11.71 (0.63, 218.15), respectively. No evidence of publication bias was found. CONCLUSIONS: Rotary instrument choice in endodontic therapy is associated with a lower incidence of PP than reciprocating instruments, while reciprocating instruments are associated with less mild PP incidence.

[Effect of the morphology of S-shaped root canals with reciprocating single file system on root canal irrigation].

OBJECTIVE: To evaluate eff ect of the morphology of simulated S-shaped root canals with Reciproc or Mtwo instruments on root canal irrigation. METHODS: A total of 40 simulated S-shaped resin blocks were randomly divided into 2 groups (n=20), which was prepared by Reciproc or Mtwo. Blue ink was injected with constant speed and volume into the canals using 30G lateral opening syringe. Th e distance from needle tip to apex and vapor lock length were measured. A type of 25# 0.04 gutt a-percha point was used to stir and remove the vapor lock. Th e time for removal of the vapor lock was recorded. Another syringe was used to inject saline into the canals and to measure the length of stagnant water. RESULTS: The distance from needle tip to apex in the Reciproc group was significantly longer than that in the Mtwo group [(4.276 ± 0.221) mm vs (3.459 ± 0.205) mm, P<0.05]. The vapor lock length in the Reciproc group was significantly longer than that in the Mtwo group [(4.472 ± 0.230) mm vs (3.668 ± 0.217) mm, P<0.05]. The time to remove vapor lock was significantly shorter in the Reciproc group than that in the Mtwo group [(10.13 ± 1.79) s vs (15.29 ± 2.15) s, P<0.05]. The length of stagnant water was also shorter in the Reciproc group than that in the Mtwo group [(1.351 ± 0.142) mm vs (2.245 ± 0.206) mm, P<0.05]. CONCLUSION: The morphology of S-shaped root canal affects the root canal irrigation. The effect of root canal irrigated by Reciproc is better than that by Mtwo.

Management and prognosis of a vital cracked tooth by occlusal veneer for 14 months: A case report.

Key Clinical Message: An occlusal veneer is an ultrathin restoration method and a minimally invasive approach that can preserve more dental tissue and provide better aesthetic outcomes, thus increasing patient satisfaction. Abstract: An occlusal veneer is an ultrathin restoration method and a minimally invasive approach that can preserve more dental tissue and provide better aesthetic outcomes, thus increasing patient satisfaction; however, no previous studies reported on treating cracked teeth using occlusal veneer. Accordingly, we described the diagnosis and treatment process of a cracked tooth using occlusal veneer in a single case. A 29-year-old male presented at our dental clinic complaining of biting pain in the mandibular molar on the right-hand side. A routine oral examination with radiography was performed to evaluate the oral condition and treatment planning. The #16 tooth had a crack line surrounding the whole distal-lingual cusp from the occlusal surface. After discussing various therapeutic options with the patient, an occlusal veneer was performed. One week after treatment with occlusal veneer, the patient had no complaints. A 14-month follow-up showed promising clinical and radiographic outcomes. Occlusal veneer is an alternative treatment option for a cracked tooth, as it can preserve more dental tissue and potentially save pulp vitality.

Biting and thermal sensitivity relief of cracked tooth restored by occlusal veneer: A 12-to 24 months prospective clinical study.

OBJECTIVES: To analyze the relief time and risk factors of biting/thermal sensitivity in cracked tooth (CT) restored using occlusal veneer. METHODS: 63 CT were analyzed, and their demographic and clinical data and medical history were collected. Patients were followed-up to examine the relief of thermal/biting sensitivity. RESULTS: The maxillary first molar was the most prevalent (N = 25, 40%). The number of crack lines on the finish line ranged from 1 to 6 while the number of crack lines through preparation on the finish line from 0 to 4. Pain relief achieved steadily to 52% for thermal and 62% for biting at 1 week to over 90% for each by 3 months and was completely resolved (no pain) for each by 12 months. Painful of lateral percussion was related to a long period of thermal sensitivity (≥1 month) after restoration with occlusal veneer. The number of crack lines through preparation on the finish line >2 was correlated with biting sensitivity (≥1 month) post-treatment. CONCLUSIONS: Most patients (>90%) became asymptomatic of biting and thermal sensitivity within 3 months of CT restored by occlusal veneer. Lateral percussion and the number of crack lines through preparation on the finish line could be significant factors affecting postoperative symptoms. CLINICAL SIGNIFICANCE: Occlusal veneer is an ultrathin restoration and had no need for restricting clinical crown height, which could protect and relief the biting/thermal sensitivity of CT without preventive root canal therapy.

Phase transformation behaviors and mechanical properties of NiTi endodontic files after gold heat treatment and blue heat treatment.

WaveOne Gold, ProTaper Gold, Reciproc Blue, ProTaper Next, WaveOne and ProTaper files were selected to compare the phase transformation behaviors and mechanical properties of nickel-titanium (NiTi) rotary files after gold heat and blue heat treatments. The reverse transformation finishing point temperatures of WaveOne Gold, ProTaper Gold, ProTaper Next and WaveOne were higher than those of the other two instruments investigated. At a deflection of 0.5 mm, the loads were significantly varied except for ProTaper Next and ProTaper Gold. At a deflection of 3.0 mm, the loads of Reciproc Blue and WaveOne Gold were significantly varied compared to WaveOne and ProTaper. Cycles to failure were reduced in the order of WaveOne Gold, Reciproc Blue, ProTaper Gold, ProTaper Next, WaveOne and ProTaper. NiTi instruments after gold heat and blue heat treatments exhibited significantly higher bending properties and cyclic fatigue resistances, representing an improved performance over traditional and M-wire instruments.

Analysis of Transcriptome in Enterococcus faecalis Treated with Silver Nanoparticles.

Silver nanoparticles can be used to effectively disinfect Enterococcus faecalis (E. faecalis) in dental root canal therapy, of which the mechanism remains unclear. In the current study, we explored the effect of silver nanoparticles on bacterial growth and changes in the transcriptome of E. faecalis using RNA-sequencing technology. Results showed that silver nanoparticles significantly inhibited growth of E. faecalis by prolonging the lag phase in a dose dependent manner. A total of 100 differentially expressed genes (DEGs) including 3 upregulated and 97 downregulated DEGs were obtained in E. faecalis after treatment with silver nanoparticles. We performed Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses on these DEGs. Functional annotation of DEGs showed that transport and metabolism, such as carbohydrate metabolic process, peptide transport, and amide transport were most significantly enriched. Dysregulated genes were significantly enriched in pathways related to carbohydrate and energy metabolism, and the TCA cycle may be a major mechanism for E. faecalis with silver nanoparticle treatment. These data indicated changes in the transcriptome of E. faecalis after silver nanoparticle treatment, thus providing a mechanism for supporting application of silver nanoparticles for disinfection of E. faecalis during and after root canal therapy.

[Comparison of the shaping ability of reciprocating instruments in simulated S-shaped canals].

OBJECTIVE: To evaluate the shaping ability of Reciproc, WaveOne,Mtwo and ProTaper instruments in simulated S-shaped root canals. METHODS: A total of 40 simulated S-shaped resin blocks were divided randomly into four groups, each group was prepared with Reciproc (group A), WaveOne (group B), Mtwo (group C) and ProTaper (group D), respectively. The preparation time and reduction of working length after preparation were measured. Pre- and postoperative images were obtained by a scanner and superimposed using Photoshop. Changes of coronal curve and apical curve curvature, as well as material removal from the inner and outer canal wall at 10 points beginning 1 mm from the end point of the canal, were measured using ImageJ. Centering ability was determined, accordingly. The data were analyzed using the one-way ANOVA and Student-Newman-Keuls. RESULTS: The preparation time of group A and group B were (42.1 ± 2.7) and (41.5 ± 3.2) s respectively, significantly less than that of group C and group D [(62.7 ± 2.8), (62.8 ± 5.2) s] (P < 0.05).Reductions of working length after preparation were not significantly different among the four groups (P > 0.05). Coronal curve curvature changes of group A, group B and group D were (4.69 ± 0.63)°, (4.15 ± 0.89)° and (4.13 ± 0.59)° respectively, significantly less than that of group C[(5.26 ± 0.70)°], P < 0.05. Apical curve curvature changes were not significantly different among the four groups (P > 0.05). At the 2 mm point, the centering ability of group A[ (-0.242 ± 0.042) mm], group B[(-0.191 ± 0.077) mm], and group D[(-0.272 ± 0.046) mm] was better than group C[(-0.343 ± 0.057 mm] significantly (P < 0.05). At the 3 mm and 4 mm point, the centering ability of group A and group B was better than group C and group D significantly (P < 0.05). Whilst at the 5 mm point, the centering ability of group D was better than group A and group B (P < 0.05). CONCLUSIONS: Reciproc and WaveOne could complete preparation faster and could maintain the original S-shaped canal curvature better than Mtwo and ProTaper, especially in the apical part.

Preparation of polypropylene superhydrophobic surface and its blood compatibility.

The blood compatibility of the superhydrophobic polypropylene surface that prepared by Erbil's method was preliminarily evaluated by platelet-rich plasma (PRP) adhesion study, fresh human whole blood contacting experiments and scanning electron microscopy, using original polypropylene films as the controls. The results show that the superhydrophobic character of polymer surface was in favor of anticoagulation.

[Prevalence of dental erosion and associated drinks in 12-year-old population of Beijing].

OBJECTIVE: To investigate the prevalence of dental erosion and associated drinks in 12-year-old adolescence of Beijing. METHODS: A random sample of 12-year-old adolescence of Beijing (n=844) was examined for dental erosion and required to fill a questionnaire of acidic drink intake. The grade criteria suitable for the survey of the dental erosion was used in the study. RESULTS: The prevalence of dental erosion was 61.8%, of which mild enamel was 74.1%, severe enamel erosion 24.9% and dentine erosion 1.0%. Statistic analysis showed that a large amount of intake of carbonated drink or juice were risk factors. CONCLUSIONS: Attention should be paid to the prevalence of dental erosion among Chinese adolescence.

[Pilot study of dental erosion and associated factors in university student volunteers].

OBJECTIVE: To investigate dental erosion and associated etiologic factors among students from one university. METHODS: A total of 179 student volunteers from one university were examined clinically for their dental erosion. Each was required to complete a questionnaire regarding potentially associated etiologic factors. A modified criteria was used to grade the severity of dental erosion. RESULTS: The prevalence of dental erosion of this group was 45.8%, mostly in enamel. Facial surfaces of anterior teeth were most vulnerable to erosion. Statistic analysis indicated that acidic diets, such as carbonated drink, fruit juice, fruit drink and banana were risk factors to dental erosion. CONCLUSIONS: The findings strongly suggest that much attention should be given to dental erosion which was probably associated with acidic diet.