Effect of icariin surface treatment on the resorption of denuded roots after replantation in rat.

AIM: Limiting the incidence of resorption associated with delayed replantation of avulsed teeth is critical for long-term tooth survival. In this study, we assessed whether icariin, a natural product with anti-osteoclastic properties, could reduce root resorption in a rat model of tooth replantation. METHODOLOGY: Cytocompatibility of icariin (10, 20, 40 and 80 µM) was evaluated by CCK-8 proliferation assay in vitro, and an osteoclastogenesis assay was performed to evaluate the effect of icariin on the differentiation of rat bone marrow macrophages and human peripheral blood monocytes into tartrate-resistant acid phosphatase-stained (TRAP+ ) multinucleated giant cells (MNGCs). Differentiation of human periodontal ligament stem cells (hPDLSCs) treated with icariin (10 µM) was also evaluated at 5, 10 and 21 days of osteogenic induction. The first maxillary molars of five-week-old male Sprague-Dawley rats were extracted, denuded of PDL, then treated either with neutralized collagen solution (Carrier control) or icariin in collagen (3 µg/µL) before replantation into their sockets. The animals were euthanized 2 weeks post-surgery for micro-computed tomography (micro-CT) imaging and histological analyses. RESULTS: Icariin was cytocompatible and significantly reduced the differentiation of TRAP+ MNGCs in a dose-dependent manner compared to the control. Moreover, icariin enhanced alkaline phosphatase activity, expression of osteogenic marker genes and proteins, and calcium deposition in hPDLSCs. Micro-CT imaging of the replanted samples demonstrated a significantly higher volume of remaining roots in the icariin-treated group than in the control group. Histological analysis revealed a marked number of resorptive lacunae with TRAP activity in the control group, whereas icariin-treated samples showed signs of functional healing and reduced osteoclastic activity. CONCLUSIONS: Icariin was biocompatible and demonstrated potent anti-osteoclastic and pro-osteogenic properties that reduced resorption and promoted functional healing of denuded roots in a rat maxillary first molar model of replantation. These findings indicate that root surface treatment with icariin may be a clinically relevant and practical method for improving the retention and survival of teeth with compromised PDL after delayed replantation following traumatic avulsion.

Biological Function and Potential Applications of Garcinol in Human Dental Pulp Stem Cells.

INTRODUCTION: The regeneration of pulp tissue is crucial for true regenerative endodontic treatment, which requires a reduction in osteogenic differentiation. Garcinol, a histone acetyltransferase inhibitor, is a natural regulator that is known to suppress the osteogenic differentiation of dental pulp stem cells. In this study, the inhibitory effect of garcinol on the osteogenic differentiation of human dental pulp stem cells (hDPSCs) was evaluated using three-dimensional culture under in vitro and in vivo conditions. METHODS: hDPSCs were obtained from caries-free third molars and cultured with 10 µM garcinol for 7 days in an ultra-low attachment plate. The cell stemness and expression of osteogenic differentiation-related genes were analyzed using reverse transcription-polymerase chain reaction and single-cell analysis. A transplantation experiment was performed in mice to investigate whether garcinol-treated hDPSCs showed restrained osteogenic differentiation. RESULTS: hDPSCs cultured in the U-shaped ultra-low attachment plate showed the highest expression of stemness-related genes. Garcinol-treated hDPSCs demonstrated downregulation of osteogenic differentiation, with lower expression of bone sialoprotein, which is related to bone formation, and higher expression of dentin sialophosphoprotein, which is related to dentin formation. However, the garcinol-treated hDPSCs did not show any alterations in their stemness. Consistent results were observed in the transplantation experiment in mice. CONCLUSIONS: Garcinol reduced the osteogenic differentiation of hDPSCs, which can contribute to true regenerative endodontic treatment.

The Effect of Mechanical Vibration on Osteogenesis of Periodontal Ligament Stem Cells.

INTRODUCTION: Appropriate occlusal forces can prevent ankylosis after tooth replantation or transplantation. However, the "proper occlusal forces" on periodontal ligament (PDL) healing have not yet been defined due to insufficient in vitro studies and uncertain in vitro models. Herein, we presented a mechanical vibration device as an in vitro model to determine such favorable occlusal forces. METHODS: Human periodontal ligament stem cells (hPDLSCs) were exposed to mechanical vibration force with 4 frequencies (30, 90, 150, and 210 rpm). Cell viability and the expression of osteogenic differentiation-related genes and proteins were tested in vitro. The calvarial transplantation experiment was performed to assess the bone formation ability of 150 rpm mechanical vibration stimulation (MVS). RESULTS: MVS at 150 and 210 rpm significantly reduced cell viability in the early stages. The 150-rpm MVS decreased osteogenic marker expression at the early time point (3 days) but had no harmful effects at the late time point (14 days). Furthermore, hPDLSC cell sheets treated with 150-rpm MVS had potential to decrease bone formation in rat calvarial defects serendipitously and facilitated functional PDL-like tissue formation. CONCLUSIONS: We found that MVS at a frequency of 150 rpm could provide a strategy for a transient reduction in the osteogenic potential of hPDLSCs and promote PDL-like tissue formation. Thus, 150-rpm MVS could be used as a controllable proper occlusal force to prevent ankylosis and promote PDL healing after tooth replantation or transplantation.

Preserving the vitality of teeth adjacent to a large radicular cyst in periapical microsurgery: a case report with 4-year follow-up.

BACKGROUND: Radicular cysts may enlarge considerably, cause extensive bone destruction, and jeopardize the integrity of the associated vital teeth. The different treatment approaches are aimed mainly at eliminating the cystic epithelial membrane while reducing the risk of injury to vital structures. Contrary to other treatment modalities, preapical surgery offers an unequivocal single occasion resolution for the patient. However, it has been associated with higher risk of collateral damages. CASE PRESENTATION: A patient presented with a large radicular cyst originating from a maxillary lateral incisor. The adjacent central and canine teeth initially failed to exhibit responses to sensibility tests but showed signs of vitality. Microsurgical management was aimed at enucleating the cystic membrane while maintaining adjacent teeth vitality. Upon careful and controlled cyst enucleation under the dental operating microscope, the neurovascular bundle of one of the involved teeth was visualized and its integrity was maintained throughout the procedure. RESULTS: The procedure was successful and follow up recalls revealed recovery of normal sensibility of tooth 11 and 13 with complete bone regeneration around their apices. CONCLUSION: Within the limitation of the present case report, we demonstrated that complete excision of large periapical cyst can be performed without sacrificing the vitality of the adjacent teeth, by preserving the integrity of their neurovascular supply through controlled microsurgical enucleation, and by a potential apical vascular repair ensuing unintended injury. Diagnosing the pulp vitality of non-offending teeth whose apices protrude into the cystic lumen is a complex process and can be misleading. Pressure from the growing cyst can inhibit vital teeth responses to neural-based sensibility tests leading to false negative results. Thus, in such cases, the use of blood perfusion-based vitality testing is recommended for correct initial diagnosis.

A One-Year Radiographic Healing Assessment after Endodontic Microsurgery Using Cone-Beam Computed Tomographic Scans.

This study aimed to evaluate one-year radiographic healing after endodontic microsurgery using CBCT with modified PENN 3D criteria and to compare the outcome with results evaluated using Molven's criteria. A total of 107 teeth from 96 patients were evaluated one year after endodontic microsurgery by using CBCT scans with modified PENN 3D criteria and periapical radiographs with Molven's criteria. Both preoperative and postoperative lesion volumes were calculated using ITK-SNAP (free software). Radiographic healing assessment using periapical radiographs and CBCT images, and preoperative and postoperative lesion volume measurements were performed independently by two examiners. The assessment using Molven's criteria resulted in 75 complete healings, 18 incomplete healings, eight uncertain healings, and six unsatisfactory healings. Based on modified PENN 3D criteria, 64 teeth were categorized as complete healing, 29 teeth as limited healing, six teeth as uncertain healing, and eight teeth as unsatisfactory healing. With the one-year follow-up, CBCT scans showed a lower healing tendency than did periapical radiography. The volumes of apical radiolucency after the surgery were reduced by 77.7% on average at one-year follow up.

The application of "bone window technique" using piezoelectric saws and a CAD/CAM-guided surgical stent in endodontic microsurgery on a mandibular molar case.

Apical surgery for a mandibular molar is still challenging for many reasons. This report describes the applications of computer-guided cortical 'bone-window technique' using piezoelectric saws that prevented any nerve damage in performing endodontic microsurgery of a mandibular molar. A 49-year-old woman presented with gumboil on tooth #36 (previously endodontically treated tooth) and was diagnosed with chronic apical abscess. Periapical lesions were confirmed using cone-beam computed tomography (CBCT). Endodontic microsurgery for the mesial and distal roots of tooth #36 was planned. Following the transfer of data of the CBCT images and the scanned cast to an implant surgical planning program, data from both devices were merged. A surgical stent was designed, on the superimposed three-dimensional model, to guide the preparation of a cortical window on the buccal side of tooth #36. Endodontic microsurgery was performed with a printed surgical template. Minimal osteotomy was required and preservation of the buccal cortical plate rendered this endodontic surgery less traumatic. No postoperative complications such as mental nerve damage were reported. Window technique guided by a computer-aided design/computer-aided manufacture based surgical template can be considerably useful in endodontic microsurgery in complicated cases.

The Application of "Bone Window" Technique in Endodontic Microsurgery.

Endodontic microsurgery for a tooth with a large periapical lesion and an intact cortical plate may necessitate the removal of extra bone and cause delayed or unfavorable healing. In such cases, the "bone window" technique offers excellent exposure to the operative field and preserves cortical bone without placing any additional graft material. In the reported cases, root-end surgery was performed on the maxillary and mandibular molars with a large periapical lesion. The bone window was fashioned with the aid of thin osteotomy instruments and repositioned to the original site at the end of the procedure, which resulted in minimizing bone loss and acted as an autologous graft for the surgical site. At 12- and 16-month follow-ups, clinical examinations and cone-beam computed tomographic scans revealed the healing of the lesion without symptoms or complications. Cone-beam computed tomographic imaging was used as a presurgical assessment tool for indication selection and precise design of the bone window. The use of a bone window in endodontic microsurgery, which appears to be a reliable technique, should be the method of preference when the large lesion is deeply positioned between intact buccal and lingual cortices.

Stress Analyses of Retrograde Cavity Preparation Designs for Surgical Endodontics in the Mesial Root of the Mandibular Molar: A Finite Element Analysis-Part II.

INTRODUCTION: The aim of this study was to investigate the influence of apical filling material and the modification made to the apical preparation design in surgical endodontics on the areas of stress concentration in the mesial root of a mandibular molar using finite element analysis. METHODS: The filling material was injected under 2 conditions (ie, with or without mineral trioxide aggregate retrograde filling). The apical preparation design was modified by extending the preparation mesially while maintaining a similar prepared area. We contained the displacement of all the nodes at the base of the supporting bone and applied a force of 150 N to the vertical axis. We analyzed stress generation and concentrations numerically for all cavity design groups. RESULTS: In the presence of retrograde filling, the von Mises stress decreased gradually according to the enlargement of the prepared cavity in the subgroups. When the retrograde filling was absent, the von Mises stress increased as the prepared cavity enlarged. The modification of the apical preparation extending in the mesial direction showed a drastic decrease in stress concentration. CONCLUSIONS: Within the limitations of this study, it was advantageous to perform mesial retrograde preparation within the mesial root dentin to maintain a balanced root dentin on both sides of the apical preparation and create a low-stress field. The surgeon should be careful not to wash out or dislodge the retrograde filling material during obturation to avoid failure of surgery.

Effects of fast- and slow-setting calcium silicate-based root-end filling materials on the outcome of endodontic microsurgery: a retrospective study up to 6 years.

OBJECTIVES: The purpose of this retrospective study was to evaluate and compare the effects of fast- and slow-setting calcium silicate-based materials (CSMs) used for root-end filling on the outcome of endodontic microsurgery. MATERIALS AND METHODS: We searched a clinical database for patients who had received endodontic microsurgery between 2001 and 2016. Included cases were divided into two groups according to the type of CSM used for root-end filling: slow-setting CSM (SCSM) and fast-setting CSM (FCSM). The cases in two groups were subjected to 1:1 nearest neighbor propensity score matching for the following variables: age, sex, tooth type, quality of canal filling, lesion type, and postoperative restoration. For each matched case, the outcome was determined as success or failure according to clinical and radiographic evaluations performed at least 1 year after surgery. Multivariate logistic regression analysis was performed to identify prognostic factors and estimate their effects. RESULTS: In total, 304 cases of endodontic microsurgery (179 SCSM and 125 FCSM) were identified, and 1:1 propensity score matching finally included 122 cases from each group. After matching, all covariates were associated with an absolute standardized difference of < 0.1. The overall success rates were 85.2% and 93.4% for the SCSM and FCSM groups, respectively (p = 0.062). Age, tooth type, lesion type, and CSM type were significantly associated with the outcome of endodontic microsurgery (p < 0.05). CONCLUSIONS: Within the limitations, the outcome of endodontic microsurgery using FCSMs was comparable with that of SCSMs. The findings suggest that the type of CSM used for root-end filling, particularly in terms of the initial setting time, could affect the outcome of endodontic microsurgery. CLINICAL RELEVANCE: FCSMs could be considered for use as root-end filling materials in endodontic microsurgery, particularly in complicated clinical situations which require rapid initial setting of the materials.

Development of a mouse model for pulp-dentin complex regeneration research: a preliminary study.

OBJECTIVES: To achieve pulp-dentin complex regeneration with tissue engineering, treatment efficacies and safeties should be evaluated using in vivo orthotopic transplantation in a sufficient number of animals. Mice have been a species of choice in which to study stem cell biology in mammals. However, most pulp-dentin complex regeneration studies have used large animals because the mouse tooth is too small. The purpose of this study was to demonstrate the utility of the mouse tooth as a transplantation model for pulp-dentin complex regeneration research. MATERIALS AND METHODS: Experiments were performed using 7-week-old male Institute of Cancer Research (ICR) mice; a total of 35 mice had their pulp exposed, and 5 mice each were sacrificed at 1, 2, 4, 7, 9, 12 and 14 days after pulp exposure. After decalcification in 5% ethylenediaminetetraacetic acid, the samples were embedded and cut with a microtome and then stained with hematoxylin and eosin. Slides were observed under a high-magnification light microscope. RESULTS: Until 1 week postoperatively, the tissue below the pulp chamber orifice appeared normal. The remaining coronal portion of the pulp tissue was inflammatory and necrotic. After 1 week postoperatively, inflammation and necrosis were apparent in the root canals inferior to the orifices. The specimens obtained after experimental day 14 showed necrosis of all tissue in the root canals. CONCLUSIONS: This study could provide opportunities for researchers performing in vivo orthotopic transplantation experiments with mice.

Using autofluorescence to detect bacterial contamination in root fractures.

OBJECTIVES: Conventional methods for detecting root fractures cannot assess their depth or bacterial contamination. This study was designed to measure the autofluorescence emitted from a root fracture, with the aim of determining whether this is a suitable method for quantifying the depth and bacterial invasion of a fracture. METHODS: This in vitro study investigated 33 mandibular second molars with periapical lesions that had been extracted after finding root fractures in endodontically treated teeth during intentional replantation or diagnostic surgery. The root fractures were scanned using a fluorescence technique, and the association between fluorescence parameters and fracture depth was analyzed. The significance of the association between the red fluorescence among autofluorescence parameters and bacterial contamination within the fracture was examined. RESULTS: When the depth of the root fractures was evaluated by micro computed tomography, the scattering of light in the fractures increased with depth, and there was a gradual increase in the quantitative fluorescence parameter indicating the deepest point (ΔFmax) in the fractures. In addition, we observed red fluorescence on the outer surface of deeper fractures. The tooth fractures exhibiting red fluorescence were evaluated for bacterial contamination associated with red-fluorescent porphyrin, which revealed bacterial invasion into these fractures. On the other hand, non-red-fluorescing fractures contained necrotic tissue, debris, and irritants. CONCLUSIONS: This viable fluorescent technique can potentially quantify the depth of root fractures and be used as a risk indicator for root fractures with periodontal inflammation. CLINICAL SIGNIFICANCE: The auto-fluorescence technique can be used to detect depth and bacterial contamination of root fractures. It is postulated that the auto-fluorescence can be used as a risk indicator of deep fractures and can replace conventional fracture detection methods.

Outcome of Endodontic Micro-resurgery: A Retrospective Study Based on Propensity Score-matched Survival Analysis.

INTRODUCTION: The purpose of this retrospective study was to evaluate and compare the outcome of endodontic micro-resurgery with that of primary endodontic microsurgery and determine prognostic factors affecting the outcome of micro-resurgery. METHODS: A clinical database was searched for endodontic microsurgery cases between 2001 and 2016. Nearest neighbor 2:1 propensity score matching for the following 5 variables was performed for cases of primary microsurgery and those of micro-resurgery: age, sex, tooth type, lesion type, and postoperative restoration. For the matched cases, the outcome was categorized as success or failure according to clinical and radiographic evaluations performed at least 1 year after surgery. Kaplan-Meier survival analysis and log-rank tests were performed to compare the outcome of primary microsurgery with that of micro-resurgery over time. For the micro-resurgery group, multivariate Cox proportional hazard regression analysis was performed to identify prognostic factors and estimate their effects. RESULTS: In total, 571 cases of endodontic microsurgery (498 primary microsurgery and 73 micro-resurgery cases) were identified, and 146 cases of primary microsurgery were matched to 73 cases of micro-resurgery through 2:1 propensity score matching. After matching, all covariates demonstrated an absolute standardized difference of <0.1. The estimated 5-year success rates were 91.6% and 87.6% for primary microsurgery and micro-resurgery, respectively (P = .594). The tooth type was found to be the only contributing factor for the outcome of micro-resurgery, with molars showing a higher probability of failure than anterior teeth (hazard ratio, 8.53; P = .002). CONCLUSIONS: Within the limitations, the findings of this study suggest that the outcome of endodontic micro-resurgery is comparable with that of primary endodontic microsurgery.

Computer-aided Design/Computer-aided Manufacturing-guided Endodontic Surgery: Guided Osteotomy and Apex Localization in a Mandibular Molar with a Thick Buccal Bone Plate.

A mandibular molar with a thick buccal bone plate is a challenging problem in endodontic surgery despite the increase in the success rate of endodontic surgery nowadays. This report describes the application of a surgical template to guide osteotomy and facilitate apex localization in a mandibular molar with a thick buccal bone plate. A 57-year-old woman visited the authors' clinic for pain in tooth 19 and was diagnosed with symptomatic apical periodontitis in this previously treated tooth. Nonsurgical retreatment was performed; however, 2 years later, the patient reported pain in the same tooth. A periapical lesion was confirmed using cone-beam computed tomographic (CBCT) imaging, and endodontic surgery on the mesial root of tooth 19 was planned. After CBCT imaging and cast scan data were transferred to implant surgical planning software, the data were superimposed. In the superimposed model, an anchor pin was designed to target the mesial root apex of tooth 19. The surgical template was then printed using a 3-dimensional printer. Endodontic microsurgery included application of this printed surgical template. A computer-aided design/computer-aided manufacturing (CAD/CAM)-guided surgical template minimized the extent of osteotomy and enabled precise targeting of the apex in this case. There were no postoperative complications. A CAD/CAM-guided surgical template is useful in endodontic surgery for complicated cases.

Evaluation of the Biodistribution of Human Dental Pulp Stem Cells Transplanted into Mice.

INTRODUCTION: Several studies have attempted to use human dental pulp stem cells (hDPSCs) for pulp-dentin complex regeneration in vitro. However, the safety of such applications should be first evaluated in vivo before their use in clinical trials. The purpose of this study was to investigate the in vivo fate of intrapulpally transplanted hDPSCs. METHODS: hDPSCs were isolated and cultured from impacted third molars. In vivo experiments were performed using 7-week-old male BALB/c nude mice. Under deep anesthesia, 1 × 105 hDPSCs were transplanted in mice via the tail vein for intravenous injection or into the pulp chamber for intrapulpal transplantation. A total of 56 mice, 28 per group, were used. Mice were sacrificed at different time points, and the numbers of hDPSCs in the organs were analyzed quantitatively. In addition, qualitative analysis was performed to detect intrapulpally transplanted hDPSCs. RESULTS: Intravenously injected hDPSCs were mostly distributed to the lungs and rarely detected in other organs at all observed time points. The hDPSCs transplanted into the pulp chamber rarely migrated to other organs over time. CONCLUSIONS: These data indicate a differential distribution of transplanted hDPSCs between the intravenous and intrapulpal route and show the safety of pulpal transplantation of hDPSCs.

Minced Pulp as Source of Pulpal Mesenchymal Stem Cells with Odontogenic Differentiation Capacity.

INTRODUCTION: Pulp tissue regeneration is becoming a reality after discovery of mesenchymal stem cells (MSCs) residing in the pulp tissues through various clinical innovations, although MSC transplantation into the pulp space has met with challenges of in vitro cell expansion and cultures. As a way to circumvent the regulatory and technical complexities of in vitro MSC culture, we investigated the use of minced pulp tissues as a source of pulpal MSCs for tissue regeneration. METHODS: We characterized the phenotype of cells explanted from minced pulp (MP), namely MP-derived MSCs (MP-MSCs), compared with dental pulp stem cells (DPSCs) established from pulp tissues by enzyme digestion. Phenotypic characterization included replication kinetics, immunophenotyping, and multilineage differentiation. Using the tooth slice model, we assessed odonto/osteogenic differentiation of DPSCs, MP-MSCs, and minced pulp tissues in situ. RESULTS: In vitro replication of MP-MSCs occurred more rapidly during the initial phase of subcultures compared with DPSCs; however, MP-MSCs arrived at senescence at population doubling 47, whereas DPSCs replicated until population doubling 64, indicating shorter replicative lifespan. MP-MSCs also demonstrated stronger odonto/osteogenic differentiation than DPSCs by alkaline phosphatase activity and the protein expression. Both MP-MSCs and DPSCs demonstrated odonto/osteogenic and adipogenic differentiation capacities. Both cell types also showed mineralized tissue formation in the tooth slice model. Seeding minced pulp tissue on poly-L-lactic acid scaffold allowed for migration of MP-MSCs from the tissues and odontogenic differentiation with dentin sialophosphoprotein expression in the tooth slice model. CONCLUSIONS: These data indicated that MP may be an alternative source of pulpal MSCs that may allow de novo pulp-dentin regeneration without the need for in vitro culture and expansion.

Revascularization-associated Intracanal Calcification: Assessment of Prevalence and Contributing Factors.

INTRODUCTION: Intracanal calcifications have been reported in endodontic cases after revascularization. The purpose of the current study was to determine the incidence of intracanal calcification and potential contributing factors in retrospective revascularization cases. METHODS: Among 37 patients who had undergone revascularization between 2010 and 2014, 29 cases were assessed with average follow-up period of 24.9 months. Clinical and radiographic examinations were performed to evaluate the treatment outcomes, eg, resolution of apical periodontitis (AP), root development, and occurrence of intracanal calcification. Radiographic assessment revealed varied calcification patterns, which were classified into calcific barrier or canal obliteration, collectively referred to as revascularization-associated intracanal calcification (RAIC). RESULTS: All 29 cases demonstrated resolution of AP, whereas continued root development with apical closure occurred in 23 of 29 cases (79.3%). RAIC was noted in 18 of 29 cases (62.1%), among which 5 of 18 cases (27.8%) were classified as calcific barrier and 13 of 18 cases as canal obliteration (72.2%). Higher frequency of RAIC was noted in the cases with induced bleeding (16 of 23 cases, 69.6%), whereas the 6 cases without induced bleeding showed RAIC at 33.4%. Also, RAIC occurred more frequently in cases medicated with Ca(OH)2 (10 of 13 cases, 76.9%) than in those medicated with antibiotic pastes (6 of 13 cases, 46.2%). CONCLUSIONS: This study indicated that RAIC is common (62.1%) among cases treated with revascularization. Multiple contributing factors may include the type of medicaments and induction of intracanal bleeding. Although RAIC does not interfere with resolution of AP, some cases may progress to complete obliteration of root canals and would impede normal function of dental pulp tissues.

Adenoid Cystic Carcinoma of Maxillary Sinus Misdiagnosed as Chronic Apical Periodontitis.

Sometimes pain originating from a non-odontogenic pathologic condition is mistaken as endodontic illness, leading to misdiagnosis. The patient can misinterpret the pain as originating from a site different from the actual site, which is known as referred pain. However, the clinician managing pain in the orofacial region needs to be well-informed about the typical signs and symptoms of non-odontogenic diseases and to be able to make the correct referral when necessary for proper diagnosis and treatment. A 43-year-old man presented to the department of conservative dentistry complaining of dental pain. Despite nonsurgical root canal treatment and curettage, he complained that the pain had spread to an area inclusive of the right side of the head and face and the right eye. The patient's pain differed from the typical endodontic pain. Therefore, the patient received a diagnosis of non-odontogenic pain and was referred to the pain clinic. Brain magnetic resonance imaging and parotid contrast images showed a mass in the right maxillary sinus. In addition, destruction in the hard palate and alveolar recess adjacent to the sinus floor was found. Infiltration into the cavernous sinus through the pterygopalatine fossa was seen. A neurosurgeon partially removed the mass by performing an osteoplastic craniotomy on the right occipital bone with the patient under general anesthesia. On the basis of the biopsy results, an adenoid cystic carcinoma was diagnosed.

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.

Kinematic Effects of Nickel-Titanium Instruments with Reciprocating or Continuous Rotation Motion: A Systematic Review of In Vitro Studies.

INTRODUCTION: This review aimed to compare the kinematic effect of nickel-titanium instruments with reciprocating and continuous rotation motion for cyclic fatigue resistance, shaping ability, apical debris extrusion, and dentinal defects or cracks. METHOD: Articles were selected for inclusion in this review if they fulfilled all of the following criteria: described in vitro studies performed on either extracted human teeth or an artificial canal model, assessed both reciprocating and rotary instruments, compared reciprocating files and rotary files for the kinematics of files, and evaluated reciprocating and rotary files regarding the aim of this study. The electronic search was undertaken in MEDLINE, Cochrane database, and manual searches, including journals, reference lists, and other reviews. RESULTS: Twelve studies were chosen for cyclic fatigue, 19 studies for shaping ability, 14 studies for apical debris extrusion, and 13 studies for dentinal defects or cracks. Most of the studies showed that reciprocating motion had a higher resistance to cyclic fatigue. Nine studies from the shaping studies reported less canal transportation by using the reciprocating motion than the continuous rotation. The reciprocating instruments tended to extrude more dentin debris than the continuous rotating instruments, but many of the studies showed conflicting results. In addition, 2 studies from the defects or cracks studies claimed the reciprocating motion produced more dentinal defects than the continuous rotating motion. CONCLUSIONS: Instruments with reciprocating motion seemed to have better resistance to cyclic fatigue with less canal transportation tendency than the instruments with continuous rotating motion.

A Randomized Controlled Study of Mineral Trioxide Aggregate and Super Ethoxybenzoic Acid as Root-end Filling Materials in Endodontic Microsurgery: Long-term Outcomes.

INTRODUCTION: The purpose of the present study was to evaluate the long-term clinical outcome of endodontic microsurgery when mineral trioxide aggregate (MTA) and super ethoxybenzoic acid (Super EBA; Harry J. Bosworth, Skokie, IL) were used as root-end filling materials. Additionally, this study aimed to compare the clinical outcome of endodontic microsurgery at the 1-year follow-up with that at the 4-year follow-up. METHODS: Two hundred sixty teeth were randomly assigned to either the MTA or Super EBA group in equal numbers using the minimization method. Endodontic microsurgery was performed according to the Yonsei protocol. The previous study of 192 teeth examined at the 1-year follow-up revealed a success rate of 95.6% for MTA and 93.1% for Super EBA. Patients were recalled 4 years after surgery, and treated teeth were classified as successes or failures with Molven's criteria. The Pearson chi-square test and the McNemar test were conducted to analyze and compare the success rates. RESULTS: A total of 182 teeth were examined at the 4-year follow-up. The success rate was 91.6% for MTA and 89.9% for Super EBA. Statistical analysis of the success rate did not show any significant difference between the 2 materials (P = .8). The overall success rate at the 4-year follow-up was 89.5%, which was slightly lower compared with 94.3% at the 1-year follow-up. However, there was no significant difference between the follow-up periods (P = .063). CONCLUSIONS: This study identified no significant difference in the 4-year success rates of MTA and Super EBA as root-end filling materials in endodontic microsurgery. Additionally, compared with short-term outcomes, long-term follow-up outcomes were not significantly different.