Anesthetic efficacy of an inferior alveolar nerve block in soft tissue and correlation between soft tissue and pulpal anesthesia.

OBJECTIVES: This study was aimed at evaluating the anesthetic success rates in various regions of soft tissue after inferior alveolar nerve (IAN) block and comparing the success rates of soft tissue anesthesia with those of pulpal anesthesia to find correlations. MATERIALS AND METHODS: Fifty-nine dental students received an IAN block injection. A total of four test sites were used for soft tissue anesthesia using a pressure algometer (PA): the corner of the lower lip vermilion border (LL); the buccal-attached gingiva of the lateral incisor (BGI), the molar (BGM), and the lingual gingiva (LG). The lateral incisor (LI) and the first molar (M1) were evaluated for pulpal anesthesia using an electric pulp tester. To evaluate whether soft tissue anesthesia can be an indicator of pulpal anesthesia, the positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS: The highest success rate for soft tissue anesthesia was seen on the LG (93.9%), followed by LL (79.6%), BGI (53.1%), and BGM (14.3%). The PPVs of LL for the M1 and Ll were 74.4 and 59.0%. The NPVs for the M1 and LI were much higher in the LL (90.0 and 100%, respectively) than in the BGI (56.5 and 69.6%, respectively). CONCLUSIONS: The highest success rate was found in the LG. Lip numbness was not an indicator of pulpal anesthesia of M1 and LI. However, if the LL was not anesthetized, the probabilities of failed pulpal anesthesia were very high in the LI and M1. CLINICAL RELEVANCE: The clinicians need to consider not doing an additional lingual nerve block after IAN block.

Randomized clinical trial of pulpotomy using a premixed injectable calcium silicate cement on mature permanent teeth with reversible pulpitis.

The aim of this two-center randomized controlled trial was to assess the outcomes and relative factors associated with pulpotomies performed using a premixed injectable calcium silicate cement, as compared to mineral trioxide aggregate in mature permanent premolar and molar teeth with reversible pulpitis. Included teeth were randomly divided into two groups according to pulpotomy material (ProRoot MTA [PMTA] group, Endocem MTA Premixed [EPM] group). After pulp exposure, the superficial pulp was either removed to a depth of 2 mm (partial pulpotomy) or completely amputated to the level of the root canal orifice (full pulpotomy). A 3-mm layer of either material was randomly placed over the pulp wound, followed by the application of a thin layer of a light-cured glass ionomer composite liner. The restoration procedure was then carried out during the same visit. After one year of treatment, the pulpotomy success rate was 94.4% (67/71), with no significant difference between the PMTA and EPM groups. The success rate was 93.9% in the PMTA group and 97.1% in the EPM group. There were no significant factors related to the procedures. EPM is a viable alternative to PMTA for single-visit pulpotomies of permanent premolars and molars.

Variations in the morphology of apical constriction affecting electronic readings: An in vitro investigation using 3D-printed tooth models.

We investigated the interference of apical constriction position and diameter on the accuracy of electronic apex locators using 3D-printed tooth models. Single-rooted tooth models with the same length, canal taper and major foramen, but variation in apical constriction position or size, were designed and 3D-printed. A mounting model was custom-made for precise measurement of both marks (0.5 and APEX/0.0) of two electronic apex locators. The electronic measurements of both devices were correlated significantly to the major foramen rather than apical constriction. The mean measurements of the group with 0.45 mm in apical constriction width were significantly shorter than those of the other groups for both marks of the two devices (p < 0.05). The variations in apical constriction position and width negatively affected the precision of the 0.5 mark of the tested devices. The 0.0 or APEX mark was consistently located the major foramen.

Clinical Efficacy of Sealer-based Obturation Using Calcium Silicate Sealers: A Randomized Clinical Trial.

INTRODUCTION: This randomized controlled clinical trial compared the clinical efficacy and outcome of a sealer-based obturation technique (SBO) with calcium silicate sealers and a continuous wave of condensation technique (CWC) with a resin-based sealer. METHODS: Root canals were prepared using rotary instruments and 2.5% sodium hypochlorite. At the next visit, patients were enrolled and randomly assigned into 2 groups on the basis of the obturation protocol: CWC with AH Plus sealer and SBO with Endoseal TCS. Patients were assessed for the level of postoperative pain using a numeric rating scale. The quality of root canal obturation was evaluated in terms of the sealer extrusion, root-filling voids, and level of root filling. The participants were recalled after at least 6 months. Healing of the teeth was determined as a decrease in Periapical Index score and resolution of symptoms. The results were statistically compared by using the χ2 test or Fisher exact test, followed by multivariate analysis with logistic regression. RESULTS: A total of 74 teeth were included in the analysis (79% recalls), and the mean follow-up period was 17 months (6-29 months). Two groups expressed identical distribution of postoperative pain (P = .973) and similar quality of root canal obturation. The total success rates were 93.2% (CWC 92.3%, SBO 94.3%) by loose criteria and 60.8% (CWC 51.3%, SBO 71.4%) by strict criteria, with no significant differences between the 2 groups. The success rate by loose criteria in teeth with sealer extrusion was significantly lower than those in teeth without sealer extrusion (P = .049). CONCLUSIONS: SBO using an Endoseal TCS could be a possible alternative to CWC using AH Plus. Sealer extrusion and postoperative pain were found to negatively impact prognosis of the endodontic treatment.

Occlusal stress distribution and remaining crack propagation of a cracked tooth treated with different materials and designs: 3D finite element analysis.

OBJECTIVE: Here we used 3D finite element analysis (FEA) to analyze and directly compare stress distribution and crack propagation in identical cracked tooth models after treatment with various materials and designs. METHODS: A 3D model of a cracked tooth was generated. We then applied eight restoration models, comprising combinations of three kinds of restoration designs (inlay, onlay, and crown) and four types of restoration materials (direct composite resin, indirect composite resin, ceramic, and gold). A 1000-N occlusal load was applied on the three reference points of the ball-shaped part in the direction of the longitudinal axis, causing crack line separation in the buccolingual direction. Stress distribution was analyzed on the occlusal surface, bottom level of the restoration, and mesiodistal longitudinal section. The stress on the lower margin of the crack surface was measured at 15 points on each model. RESULTS: Ceramic inlay and onlay showed stress concentration at the restoration bottom, and low stress on the lower margin of the crack surface. Direct and indirect resin restorations exhibited low stress on the restoration bottom, and high stress on the proximal end of the lower margin of the crack surface. With a resin-unfilled gold crown, stress was concentrated on the crown bottom and the lower margin of the crack surface. Direct resin filling inside the gold crown yielded significantly decreased stress on both areas. SIGNIFICANCE: Our results suggest that inlay and onlay ceramic restorations, and gold crown with resin filling inside, are advantageous methods for preventing further crack propagation.

Clinical Outcomes after Apical Surgery on the Palatal Root of the Maxillary First Molar Using a Palatal Approach.

INTRODUCTION: Clinicians are often reluctant to use the palatal approach in apical surgery for the maxillary first molar. This study aimed to investigate the outcomes and complications associated with apical surgery on the palatal root of the maxillary first molar by using a palatal approach. METHODS: We searched for patients who underwent apical surgery with a palatal approach on the palatal root of the maxillary first molar between March 2010 and September 2017 by a single operator. A total of 46 teeth from 46 subjects were included, and they were examined at 6 and 12 months after surgery and annually thereafter. To evaluate whether there was nerve damage on the surgical side, a pinprick test and cotton swab test were used with a 0-10 numerical rating scale, and the results were statistically compared by using the Wilcoxon signed-rank test. RESULTS: Of the total 35 recall cases (recall rate, 76%; average follow-up time, 3.5 years), success was considered achieved in 32; 30 cases showed complete healing, and 2 had incomplete healing. Three cases resulted in failure, all occurring within 1 year after surgery. The pinprick test results showed that all the numerical rating scale scores were higher than 7, and the responses on the surgical site were not statistically different from those on the contralateral site (P = .109). All subjects showed normosensitivity to the cotton swab test. CONCLUSIONS: Apical surgery on the palatal root of the maxillary first molar using a palatal approach was predictable and successful, and the number of complications resulting from artery and nerve damage was small.

Clinical Outcomes after Intentional Replantation of Periodontally Involved Teeth.

INTRODUCTION: Periodontal involvement has been thought to be a contraindication for intentional replantation. This retrospective study aimed to assess clinical outcomes after intentional replantation of teeth with periodontal involvement and to explore potential predictors of outcomes. METHODS: Teeth with a history of intentional replantation between March 2000 and December 2014 and with 1 or 2 preoperative periodontal pockets ≥6 mm among 6 sites evaluated per tooth were included. A total of 103 teeth were included, and 74 teeth were followed up for more than 6 months. Outcomes were assessed as improved (a decrease in the number and depths of periodontal pockets and the size of periapical radiolucency and no external root resorption or sign/symptoms) or failed. Data were analyzed with Kaplan-Meier survival analysis and a Cox proportional regression model. RESULTS: Cumulative improved rates declined from 89% at 1 year to 68% at 4 years. A Cox proportional regression model identified the patient's age (P = .049; hazard ratio, 2.552) and the number of preoperative periodontal pockets with a depth ≥6 mm (P = .041; hazard ratio, 2.523) as predictors of outcomes in the replantation of periodontally involved teeth. CONCLUSIONS: Periodontal involvement is not an absolute contraindication to intentional replantation. The teeth with 1 preoperative periodontal pocket ≥6 mm and the subjects aged ≤40 years had 2.5 times and 2.6 times lower probability of failure, respectively, than the teeth with 2 pockets and the subjects aged >40 years. Therefore, these factors need to be carefully considered for intentional replantation.

Effect of Topical Anesthesia on Pain from Needle Insertion and Injection and Its Relationship with Anxiety in Patients Awaiting Apical Surgery: A Randomized Double-blind Clinical Trial.

INTRODUCTION: We aimed to simultaneously investigate the effects of topical anesthesia on needle insertion and injection pain in the labial mucosa of the maxillary central incisors of patients awaiting apical surgery and to assess the relationship between patients' anxiety and pain scores. METHODS: Forty-four patients scheduled for apical surgery of the maxillary anterior incisor or canine were included, and all completed the Modified Dental Anxiety Scale (MDAS) questionnaire. One piece of Xylocaine (AstraZeneca, Sodertalje, Sweden) gauze was applied to the right or left side of the labial vestibule below the central incisor according to a randomization process, and 1 piece of water gauze was applied to the contralateral side of the labial vestibule. Each piece of gauze remained in place for 2 minutes. The subjects were asked to rate their pain according to the numeric rating scale immediately after needle insertion and anesthetic solution injection. RESULTS: Topical anesthetic application significantly reduced both insertion- and injection-related pain. Injection pain was significantly higher than insertion pain throughout the experiment. The difference in pain scores between the placebo and topical anesthetic groups was significantly greater for insertion pain than injection pain. The group with higher MDAS scores showed significantly higher pain scores, except for insertion pain reported by the topical anesthetic group, which did not show a significant difference between MDAS score groups. CONCLUSIONS: The topical anesthetic was highly effective for both insertion and injection pain during infiltration anesthesia in the maxillary central incisors. Highly anxious patients reported higher pain scores; however, topical anesthetics reduced the effect of anxiety on increasing pain.

Proteome Expression in Human Periodontal Ligament after Delayed Hypothermic Preservation.

INTRODUCTION: Previous occasional successes after delayed replantation suggest that the presence of viable cells may not be the only factor for successful periodontal regeneration in delayed replantation. Various other factors such as proteins or the extracellular matrix (ECM) may play a role in this process. The purpose of this study was to characterize changes in the proteome components of periodontal ligament (PDL) tissue after hypothermic preservation of the tooth. METHODS: Extracted teeth were divided into 4 groups: immediate sampling, sampling after 1 week of preservation at 4°C, sampling after 2 weeks of preservation at 4°C, and sampling after 1 week of dry storage at room temperature as a negative control. PDL tissues were collected from the root and stored immediately in liquid nitrogen. The tissues were subjected to 2-dimensional gel electrophoresis, and spot selection was executed. Selected spots that maintained the protein volume were then processed with matrix-assisted laser desorption and ionization time-of-flight mass spectrometry to identify the nature of the proteins. RESULTS: Thirty-five selected spots were analyzed. Sixteen spots were identified as vimentin, and 3 spots were type VI collagen. The size of the 16 vimentin spots decreased gradually with increasing storage time, from 0 to 2 weeks, and decreased rapidly after dry storage. However, only the dry storage group differed significantly from the immediately sampled group. CONCLUSIONS: Vimentin was the most prominent protein followed by type VI collagen in volumetrically maintained protein spots. Although these proteins are known to be closely related with ECM integrity, the role of these proteins in delayed replantation is beyond the scope of this study. Further studies are needed to elucidate the possible role of these proteins for periodontal healing of delayed replantation.

Retention and Healing Outcomes after Intentional Replantation.

INTRODUCTION: Intentional replantation is an alternative to tooth extraction and prosthetic replacement when conventional endodontic treatment modalities are unfeasible or contraindicated. This study assessed tooth retention and healing after intentional replantation and explored predictors of these outcomes. METHODS: Data of intentional replantation procedures performed between March 2000 and December 2010 were collected prospectively, excluding teeth with preoperative periodontal and root defects. A cohort of 159 teeth was followed up for 0.5-12 years. Retention and healed status without complications (periapical radiolucency, external root resorption, ankylosis, signs/symptoms, probing ≥6 mm) was recorded and analyzed with Kaplan-Meier survival analysis and Cox proportional hazard regression model (P < .05). RESULTS: Complications leading to extraction occurred in 8 of 159 teeth (5%). Kaplan-Meier survival function suggested 93% cumulative 12-year retention. Cumulative healed rates declined from 91% at 6 months to 77% at 3 years. The healed rate was significantly lower for maxillary teeth without preoperative periapical radiolucency, replanted in more than 15 minutes, and root-end filled with ProRoot MTA. Cox regression identified extraoral time ≤15 minutes as predictor of complication-free healing (P < .04; hazard ratio, 2.767; 95% confidence interval, 1.053-7.272). CONCLUSIONS: This prospective cohort study of contemporary intentional replantation suggested a cumulative 12-year retention rate of 93% and healed rate of 77% after 3 years. Healing occurred 1.7 times more frequently in teeth replanted within 15 minutes. Although most complications occurred within 1 year after replantation, follow-up should extend for at least 3 years to capture late complications.

Does apical root resection in endodontic microsurgery jeopardize the prosthodontic prognosis?

Apical surgery cuts off the apical root and the crown-to-root ratio becomes unfavorable. Crown-to-root ratio has been applied to periodontally compromised teeth. Apical root resection is a different matter from periodontal bone loss. The purpose of this paper is to review the validity of crown-to-root ratio in the apically resected teeth. Most roots have conical shape and the root surface area of coronal part is wider than apical part of the same length. Therefore loss of alveolar bone support from apical resection is much less than its linear length.The maximum stress from mastication concentrates on the cervical area and the minimum stress was found on the apical 1/3 area. Therefore apical root resection is not so harmful as periodontal bone loss. Osteotomy for apical resection reduces longitudinal width of the buccal bone and increases the risk of endo-perio communication which leads to failure. Endodontic microsurgery is able to realize 0 degree or shallow bevel and precise length of root resection, and minimize the longitudinal width of osteotomy. The crown-to-root ratio is not valid in evaluating the prosthodontic prognosis of the apically resected teeth. Accurate execution of endodontic microsurgery to preserve the buccal bone is essential to avoid endo-perio communication.

Prognostic factors for clinical outcomes according to time after direct pulp capping.

INTRODUCTION: Direct pulp capping is a treatment option for teeth with carious-exposed pulp. Because pulp capping studies have exhibited fluctuations in success rates according to different follow-up times, investigating the clinical pulpal survival rate and the potential factors contributing to the survival with respect to time is necessary. METHODS: A total of 175 patients treated between November 2007 and August 2010 met the inclusion criteria. During the follow-up, we investigated 7 clinical variables with respect to the survival of the pulp capping treatment: sex, age, maxilla versus mandible, tooth position, capping materials, temporary filling materials, and exposure site. Survival analysis was performed using the Kaplan-Meier method and the Cox proportional hazard regression model. RESULTS: The Kaplan-Meier survival curves and log-rank tests revealed that only age, exposure site, and capping material had significant effects on the pulpal survival rate (P< .05). A Cox regression model showed that mineral trioxide aggregate was the sole factor affecting the survival of the treated pulps (P< .05). In the analyses performed separately according to time, there was no conspicuous factor that affected the survival rate before 100 days. However, after 100 days, the type of pulp capping material was the single most important factor influencing the survival rate (P< .05). CONCLUSIONS: The results of this study indicated that careful patient selection and the type of pulp capping material should be taken into consideration when performing a pulp capping treatment.