Application of Nanomaterials in Endodontics.

Recent advancements in nanotechnology have introduced a myriad of potential applications in dentistry, with nanomaterials playing an increasing role in endodontics. These nanomaterials exhibit distinctive mechanical and chemical properties, rendering them suitable for various dental applications in endodontics, including obturating materials, sealers, retro-filling agents, and root-repair materials. Certain nanomaterials demonstrate versatile functionalities in endodontics, such as antimicrobial properties that bolster the eradication of bacteria within root canals during endodontic procedures. Moreover, they offer promise in drug delivery, facilitating targeted and controlled release of therapeutic agents to enhance tissue regeneration and repair, which can be used for endodontic tissue repair or regeneration. This review outlines the diverse applications of nanomaterials in endodontics, encompassing endodontic medicaments, irrigants, obturating materials, sealers, retro-filling agents, root-repair materials, as well as pulpal repair and regeneration. The integration of nanomaterials into endodontics stands poised to revolutionize treatment methodologies, presenting substantial potential advancements in the field. Our review aims to provide guidance for the effective translation of nanotechnologies into endodontic practice, serving as an invaluable resource for researchers, clinicians, and professionals in the fields of materials science and dentistry.

Exploring approaches to pulp vitality assessment: A scoping review of nontraditional methods.

INTRODUCTION: Diagnostic procedures for pulp vitality assessment are a crucial aspect of routine dental practice. This review aims to provide a comprehensive overview of nontraditional techniques and methodologies for assessing pulp vitality, specifically exploring promising approaches that are currently not used in dental practice. METHODS: The study protocol was registered a priori (https://osf.io/3m97z/). An extensive electronic search was conducted across multiple databases, including MEDLINE via PubMed, Scopus, Web of Science, and Embase. Inclusion criteria were guided by the research question based on the PCC model as follows: "What are the potential nontraditional techniques (Concept) for assessing pulp vitality (Population) in the field of endodontics or clinical practice (Context)?" Studies were included that explored possible approaches to pulp vitality assessment, utilizing a range of techniques, whilst any studies using traditional pulp tests (cold, heat, and electric stimulation) or well-known methods (pulse oximetry and laser Doppler flowmetry) were excluded. Reviewers independently screened articles and extracted data. A patent search was also performed. RESULTS: Of 3062 studies, 65 were included that described nontraditional approaches for assessing pulp vitality. These included a range of optical diagnostic methods, ultrasound Doppler flowmetry (UDF), magnetic resonance imaging (MRI), terahertz imaging, tooth temperature measurements, as well as invasive methodologies, including 133xenon washout, radioisotope-labelled tracers, hydrogen gas desaturation, intravital microscopy and fluorescent microspheres isotope clearance. The patent search included artificial intelligence and biomarkers methods. CONCLUSIONS: This review provides details for potential innovative tests that may directly describe pulp vitality. Importantly, these methods range from clinically impractical through to promising methods that may transform clinical practice. Several nontraditional techniques have the potential to enhance diagnostic accuracy and could provide valuable insights into the assessment of pulp vitality in challenging clinical scenarios.

The application of lasers in vital pulp therapy: clinical and radiographic outcomes.

The main purpose of vital pulp therapy (VPT) is to preserve the integrity and function of the pulp. A wide variety of materials and techniques have been proposed to improve treatment outcomes, and among them, the utilization of lasers has gained significant attention. The application of lasers in different stages of VPT has witnessed remarkable growth in recent years, surpassing previous approaches.This study aimed to review the applications of lasers in different steps of VPT and evaluate associated clinical and radiographic outcomes. An electronic search using Scopus, MEDLINE, Web of Science and Google Scholar databases from 2000 to 2023 was carried out by two independent researchers. The focus was on human studies that examined the clinical and/or radiographic effects of different laser types in VPT. A total of 4243 studies were included in this narrative review article. Based on the compiled data, it can be concluded that although current literature suggests laser may be proposed as an adjunct modality for some procedural steps in VPT, more research with standardized methodologies and criteria is needed to obtain more reliable and conclusive results.

The application of lasers in vital pulp therapy: a review of histological effects.

Vital pulp therapy (VPT) is primarily intended to preserve the vitality of pulp tissues, which have been exposed for any reason. Various materials and techniques have been proposed to improve treatment outcomes, including the use of lasers. This study aimed to review the histological results of different dental lasers including low-level lasers, carbon dioxide (CO2), erbium-doped yttrium aluminum garnet laser (Er:YAG), neodymium-doped yttrium aluminum garnet (Nd:YAG), erbium, chromium:yttrium-scandium-gallium-garnet (Er,Cr:YSGG) lasers, and diode lasers for VPT. This focused review included a comprehensive electronic search of Scopus, MEDLINE, Web of Science, and Google Scholar databases from 2000 to 2022 by two independent investigators. Different combinations of keywords were used, and reference mining of related papers was done. The review included studies related to histologic evaluation of laser-assisted vital pulp therapy that stated the laser parameters that were used. Articles with radiographic or clinical assessments or articles lacking necessary data were excluded. Non-English articles were excluded unless their abstract was in English and encompassed the necessary data. Most studies indicated the efficacy of lasers for reduction of inflammation, acceleration of healing, and increasing the thickness of dentinal bridge. According to the evidence, lasers used in combination with pulp capping agents are beneficial to enhance the success rate of VPT.

Comparison of Cytotoxicity between Mineral Trioxide Aggregate Mixed with Chlorhexidine and Common Endodontic Regeneration Medicaments on Periodontal Ligament Stem Cells: an in Vitro Study.

Objectives: The combination of mineral trioxide aggregate (MTA) and 2% chlorhexidine (CHX) has been recently introduced as an intracanal medicament. The aim of this study was to evaluate the potential cytotoxic effects of MTA mixed with 2% chlorhexidine gel on human periodontal ligament stem cells (PDLSCs) and compare it with other common endodontic regeneration medicaments. Materials and Methods: Minimum inhibitory concentration and minimum bactericidal concentration of six experimental groups against Enterococcus faecalis was determined. The study groups consisted of RetoMTA mixed with 2% chlorhexidine gel (MTA+CHX), calcium hydroxide (CH), CH mixed with CHX gel, two concentrations of double antibiotic paste, and 2% CHX. The direct cytotoxic effect of minimum bactericidal concentration was evaluated by MTT on PDLSCs on days 1, 3, and 7. One-way ANOVA and post hoc tests were used for data analysis (P<0.05). Results: The viability of cells treated with MTA+CHX decreased significantly over time (P<0.05) making this group the most cytotoxic intracanal medicament on the 3rd and 7th days of treatment. On day one, the highest viability percentage was detected in the CH+CHX group followed by the CHX group. On day 3, CH+CHX and CHX groups displayed the highest viability percentage. On day 7, the highest viability was observed in the CHX group, which showed no significant difference with the control group (P=0.12). Conclusion: Regarding the antimicrobial potency of intracanal medicaments at minimum bactericidal concentration levels, CHX gel appears to be the least cytotoxic drug, while MTA+CHX shows the highest reduction in viability percentage.

Pulpal anesthesia of maxillary first molars using 4% articaine infiltration in patients with symptomatic irreversible pulpitis: a randomized controlled clinical trial.

OBJECTIVES: This study aimed to compare the anesthetic efficacy of 1.8 mL (one cartridge) and 3.6 mL (two cartridges) buccal infiltration and buccal plus palatal infiltration of 4% articaine in maxillary first molar teeth with symptomatic irreversible pulpitis. MATERIALS AND METHODS: This randomized single-blind clinical trial was conducted on 45 patients with symptomatic irreversible pulpitis of maxillary first molars (Trial Registration No: IRCT2015011020238N2_2015). The patients were randomly divided into three groups (n = 15) for buccal infiltration of 1.8 mL articaine plus 1:100,000 epinephrine (group 1), buccal infiltration of 3.6 mL articaine (group 2), and buccal infiltration of 1.8 mL articaine plus palatal infiltration of 0.5 mL articaine (group 3). The pain intensity was measured by the Heft-Parker visual analog scale (VAS) during injection and during access cavity preparation. No pain or mild pain during treatment was considered as successful anesthesia. Data were analyzed by the Tukey's post hoc test. RESULTS: The three groups had a significant difference in frequency of the perceived pain during injection (P = 0.01). A higher volume of 4% articaine and injection of articaine in both buccal and palatal sides provided a significantly higher anesthesia success rate (P = 0.049 and P < 0.01, respectively). The highest success rate was recorded in group 3 (93.33%) followed by group 2 (80%) and then group 1 (53.33%). CONCLUSIONS: Increasing the administered volume of 4% articaine with 1:100,000 epinephrine and addition of palatal infiltration to buccal infiltration of articaine can significantly increase the success of anesthesia in maxillary first molars with symptomatic irreversible pulpitis. CLINICAL RELEVANCE: Achieving deep anesthesia in teeth with irreversible pulpitis is a critical parameter in management of patients who are in urgent need of root canal treatments.

Silver Nanoparticles and Their Therapeutic Applications in Endodontics: A Narrative Review.

The efficient elimination of microorganisms and their byproducts from infected root canals is compromised by the limitations in conventional root canal disinfection strategies and antimicrobials. Silver nanoparticles (AgNPs) are advantageous for root canal disinfection, mainly due to their wide-spectrum anti-microbial activity. Compared to other commonly used nanoparticulate antibacterials, AgNPs have acceptable antibacterial properties and relatively low cytotoxicity. Owing to their nano-scale, AgNPs penetrate deeper into the complexities of the root canal systems and dentinal tubules, as well as enhancing the antibacterial properties of endodontic irrigants and sealers. AgNPs gradually increase the dentin hardness in endodontically treated teeth and promote antibacterial properties when used as a carrier for intracanal medication. The unique properties of AgNPs make them an ideal additive for different endodontic biomaterials. However, the possible side effects of AgNPs, such as cytotoxicity and tooth discoloration potential, merits further research.

Assessment of the diagnostic accuracy of strip and furcal perforations in different sizes by cone beam computed tomography.

OBJECTIVE: Root perforation is an adverse event that may accidentally occur during root canal treatment and can adversely affect the treatment plan and tooth prognosis. This study aimed to assess the accuracy of cone beam computed tomography (CBCT) for detecting the strip and furcal perforations with different sizes. METHODS: The mesiolingual canals of 155 extracted human mandibular first molars were instrumented and randomly divided into four experimental groups and one control group (n = 31). Furcal (in the pulp chamber floor) and strip perforations with 0.5, 1, 1.5, and 2 mm in diameter were manually created. The teeth were randomly mounted in bovine ribs and scanned using CBCT. Two radiologists unaware of the study groups observed the images and reported the greatest perforation diameter. The inter-observer agreements were calculated. The diagnostic accuracy was compared for furcal and strip perforations with different sizes. RESULTS: The inter-observer agreement for detecting furcal and strip perforations with different sizes were good. The diagnostic accuracy was 100% for the absence of perforation in each group. CONCLUSIONS: CBCT can detect the absence of perforation with high accuracy. The diagnostic accuracy of CBCT in the presence of strip and furcal perforation with different sizes was not significant.

Oral microbiota in cancer: could the bad guy turn good with application of polyphenols?

The human oral cavity is comprised of dynamic and polynomial microbes which uniquely reside in the microenvironments of oral cavities. The cumulative functions of the symbiotic microbial communities maintain normal homeostasis; however, a shifted microbiota yields a dysbiosis state, which produces local and systemic diseases including dental caries, periodontitis, cancer, obesity and diabetes. Recent research reports claim that an association occurs between oral dysbiosis and the progression of different types of cancers including oral, gastric and pancreatic ones. Different mechanisms are proposed for the development of cancer, such as induction of inflammatory reactions, production of carcinogenic materials and alteration of the immune system. Medications are available to treat these associated diseases; however, the current strategies may further worsen the disease by unwanted side effects. Natural-derived polyphenol molecules significantly inhibit a wide range of systemic diseases with fewer side effects. In this review, we have displayed the functions of the oral microbes and we have extended the report regarding the role of polyphenols in oral microbiota to maintain healthy conditions and prevention of diseases with emphasis on the treatment of oral microbiota-associated cancer.

Evaluation of the effect of the photobiomodulation therapy on the pain related to dental injections: A preliminary clinical trial.

BACKGROUND: Pain from dental injections is a common reason why people fear dentistry and avoid dental treatment. Thus, researchers have attempted to find methods to decrease dental injection pain. OBJECTIVES: Considering the analgesic effect of the photobiomodulation therapy (PBMT), the aim of this study was to evaluate the effects of PBMT on the pain caused by dental anesthetic injections. MATERIAL AND METHODS: This randomized, split-mouth, triple-blind clinical trial evaluated 60 bilateral canine teeth in 30 dental students. After the random selection of the test (laser) quadrant, the injection site was irradiated with a 940 nm diode laser. Buccal infiltration anesthesia was then administered by injecting lidocaine plus epinephrine with a short needle. The level of pain experienced during the injection was determined using a 100-millimeter visual analog scale (VAS). The same procedure was performed for the control (no laser) quadrant, with the difference being that the laser handpiece was turned on, but no radiation was administered. The 2 groups were compared using the non-parametric Wilcoxon signed-rank test. RESULTS: The mean VAS pain scores were 21.2 ±15.7 for the laser quadrant and 27.9 ±18.9 for the control quadrant; this difference was statistically significant (p = 0.030), but did not seem to be clinically relevant. CONCLUSIONS: The photobiomodulation therapy prior to dental anesthetic injections has no clinical advantage for reducing injection pain.

Residual antibacterial effects of a mixture of silver nanoparticles/calcium hydroxide and other root canal medicaments against Enterococcus faecalis.

Background/purpose: Intracanal medicaments with high residual inhibition effects are used to achieve successful endodontic treatment and prevent reinfection. This in vitro study aimed to assess antimicrobial residual effects of different intracanal medicaments against Enterococcus faecalis (E. faecalis) in root dentin one week after drug therapy. Materials and methods: Seventy human teeth were standardized to have 15 mm of length and were prepared by ProTaper rotary system. The teeth were randomly divided into six experimental (n = 10) and two control (n = 5) groups and subjected to drug therapy as follows; group CHX: 2% chlorhexidine gel, group CH: calcium hydroxide paste, group CH/CHX: mixture of calcium hydroxide and 2% CHX, group TAP: triple antibiotic paste, group DAP: double antibiotic paste, group CH/AgNPs: mixture of CH paste and silver nanoparticle suspension. After one week, the medicaments were removed from the root canals and E. faecalis was inoculated into the canals. The teeth were incubated at 37 °C for 24 h. Using a size 40 hedstrom file, dentin chips were collected and number of colony forming units were counted. Results: The difference between all experimental groups was statistically significant in this regard (P < 0.05) except for DAP and TAP groups, in which, no bacterial colony was noted after culture. After DAP and TAP, the lowest colony count was noted in CH/AgNPs, CH/CHX and CHX groups. The highest colony count was noted in CH group. Conclusion: Our results showed favorable residual antibacterial effects of TAP, DAP and CH/AgNP medicaments after one week of application.

The effect of different intracanal medicaments on the dislodgement resistance of mineral trioxide aggregate.

BACKGROUND: This study aimed to assess the effect of different commercially used calcium hydroxide [Ca(OH)2], the mixture of Ca(OH)2 + silver nanoparticles (AgNPs), and other intracanal medicaments on dislodgement resistance of mineral trioxide aggregate (MTA) to root canal dentin in short- and long-term application. METHODS: Forty-six human single-rooted maxillary teeth were sectioned horizontally at mid-root into 1 mm thick slices. The lumen of the slices was standardized using #2-#5 Gates Glidden drills to a standard diameter of 1.3 mm in all samples. After smear layer removal, the samples were randomly divided into eight groups (n = 20) and treated with the following medicaments; Ca(OH)2 paste, Calcipex, Metapex, chlorhexidine (CHX), Ca(OH)2/CHX paste, Ca(OH)2/AgNPs, triple antibiotic paste and control group (normal saline). The samples were then incubated at 37 °C with 100% humidity for 1 week. Next, half of the teeth in each group (n = 10) were removed from the incubator and washed in an ultrasonic bath. ProRoot MTA was placed in the canal lumen and the samples were incubated at 37 °C and 100% humidity for 48 h to allow complete setting of MTA. The remaining half in each group (n = 10) was subjected to the same process after 1 month of application of medicaments. The dislodgement resistance of MTA to root dentin was measured. The data were analysed using two-way ANOVA and Tukey's post hoc test. RESULTS: No significant difference was noted in dislodgement resistance of samples after 1 week and 1 month in any group (P > 0.05). The only significant difference was noted between the control and CHX groups and the higher dislodgement resistance was recorded in the CHX group (P = 0.006). No other significant differences were noted between the groups (P > 0.05). CONCLUSION: Duration of application and the type of intracanal medicament do not affect the dislodgement resistance of MTA to root dentin. Although there was no statistically significant difference in the dislodgment resistance of MTA between the medicaments, CHX had a promising effect.

Comparison of the effect of QMix and conventional root canal irrigants on push-out bond strength of fiber post to root dentin.

OBJECTIVES: This study aimed to assess the effect of application of QMix and common root canal irrigating solutions on the bond strength of fiber post to root dentin. MATERIAL AND METHODS: In this in-vitro study, 60 extracted incisor teeth were decoronated such that 15 mm of root length remained. The canals were prepared with ProTaper rotary system to F5 and filled with gutta-percha and AH26 sealer. Prior to post placement, the teeth were divided into four groups based on the type of final irrigating solution namely saline, 5.25% NaOCl, 2% chlorhexidine, and QMix. The fiber posts were then cemented with Panavia F2 resin cement. The roots were sectioned perpendicular to their longitudinal axis, and four sections with 1 mm thickness were made at the middle and coronal thirds of the roots. The push-out bond strength of fiber posts was measured by a universal testing machine in megapascals. Data were analyzed by two-way ANOVA and Tukey's test. RESULTS: The maximum and minimum bond strength values were noted in QMix and NaOCl groups in both the middle and coronal third of the root, respectively. But, there was no significant difference between the push-out bond strength in the middle or coronal third of the root (p = 0.054). Adhesive failure was the most common mode of failure in all groups. CONCLUSION: Use of QMix for post space irrigation does not compromise the bond strength of fiber post to root dentin, and can be used for final rinsing of the post space.

Effect of Transcodent painless needles on injection pain in maxillary anterior infiltration: a split-mouth controlled randomized clinical trial.

OBJECTIVES: The present study aimed to determine the pain perceived during supraperiosteal (infiltration) injection in anterior maxillary region by Transcodent painless needle tips in comparison to the regular needle tips. MATERIAL AND METHODS: In this split-mouth controlled randomised clinical trial, 30 patients were selected as candidates for cosmetic treatment who needed infiltration injections on both sides of canine area. They were each administered 0.9 mL of Lidocaine HCl 2% with epinephrine 1:100,000 in the buccal vestibules using two types of needle tips, Transcodent painless needle tip or regular needle tip. Immediately after the injection, the pain was measured using a 100 mm visual analog scale. The level of pain was statistically analyzed in the two groups using the parametric paired t-test. A 5% significance level was considered for statically significant difference between two means. RESULTS: In accordance with the results, the patients' level of pain were estimated as 18.3 ± 10.7 mm with Transcodent painless needle tips and 43.1 ± 13.1 mm in regular needle tip (p < 0.05). CONCLUSION: The Transcodent painless needle showed considerable reduction of pain in the anterior maxillary infiltration when compared to the regular needle tips.

Bacterial leakage assessment in root canals sealed with AH Plus sealer modified with silver nanoparticles.

BACKGROUND: Successful endodontic therapy requires prevention of bacterial leakage between the root canal filing and root-canal walls. Sealing quality of a root canal filling depends strongly on the sealing ability of the sealer used. The present study aimed to evaluate the bacterial leakage resistance of AH Plus sealer modified with silver nanoparticles. METHODS: Forty sound teeth were obturated using lateral compaction technique except for five teeth as the negative controls. After considering five teeth as the positive controls (filled without sealer), the remaining teeth were assigned to two groups (n = 15) in terms of the sealer used (AH Plus sealer and silver nanoparticle-modified AH Plus). Bacterial leakage was evaluated in saliva using the two-chamber technique in every 24 h. When all the samples in the test groups were contaminated, the study was terminated. The data were analyzed with log-rank statistical test. RESULTS: All samples in both experimental groups were contaminated during the 3-months period of observation. There was no significant difference in contamination time between study groups (P > 0.05). CONCLUSIONS: Silver nanoparticles used in tested concentration did not improve the bacterial leakage resistance of AH Plus sealer.

Effect of different activations of silver nanoparticle irrigants on the elimination of Enterococcus faecalis.

OBJECTIVES: This study aimed to compare the efficacy of silver nanoparticles (AgNPs) irrigating solution alone and following activation with photon-induced photoacoustic streaming (PIPS), photodynamic therapy (PDT) with indocyanine green (ICG), passive ultrasonic irrigation (PUI), and manual dynamic activation (MDA) method for elimination of Enterococcus faecalis (E. faecalis) from the root canal system. MATERIALS AND METHODS: A total of 59 extracted human single-rooted teeth were collected and prepared. E. faecalis was inoculated into the root canals and incubated for 4 weeks. The teeth were then randomly divided into five experimental groups (n = 10): the AN group, irrigation with AgNPs alone; the AN/ICG/DL group, irrigation with AgNPs and ICG, then activation with diode laser; the AN/PIPS group, irrigation with AgNPs and activation with 0.3 W Er: YAG laser; the AN/MDA group, irrigation with AgNPs and activation with tapered gutta-percha; and the AN/PUI group, irrigation with AgNPs and activation with ultrasonic. Also, two control groups of irrigation with 2.5% sodium hypochlorite (n = 5) and no intervention (n = 4) were also used. Samples were collected from the dentinal chips before and after the intervention, and the percentage of reduction in colony count was calculated. RESULTS: A significant reduction in E. faecalis colony count was noted in all groups (P < 0.05). Maximum reduction in colony count was noted in AN/PIPS and AN/PUI groups by 91.03 and 91.29%, respectively. Minimum reduction was noted in the AN group alone. CONCLUSION: Activation with PUI and PIPS enhanced the efficacy of AgNPs irrigating solution for elimination of E. faecalis from the root canal system. CLINICAL RELEVANCE: AgNPs activated by ultrasound or PIPS can be used as an adjunct for disinfection of the root canal system in endodontic treatment.

Comparative evaluation of anesthetic efficacy of inferior alveolar nerve block and inferior alveolar nerve block plus buccal or lingual infiltration using articaine in mandibular molars with irreversible pulpitis: a preliminary prospective randomized single-blind clinical trial.

OBJECTIVES: This study was designed as a prospective randomized single-blind clinical trial to compare the anesthetic efficacy of inferior alveolar nerve block (IANB), IANB plus buccal infiltration, and IANB plus lingual infiltration of 4% articaine with 1:100,000 epinephrine in mandibular molars with irreversible pulpitis. METHOD AND MATERIALS: Sixty healthy volunteers who had a first or second mandibular molar diagnosed with irreversible pulpitis participated in the present study. This study was composed of three arms for the first molar and three arms for the second molar. Subjects in test arm A received two IANB injections (3.6 mL). Subjects in test arm B received 1.8 mL IANB injection plus 1.8 mL buccal infiltration. Subjects in test arm C received 1.8 mL IANB injection plus 1.8 mL lingual infiltration. Articaine (4%) with 1:100,000 epinephrine was used for all injections. The subject's pain during access preparation and pulp extirpation was recorded on the Heft-Parker visual analog scale. Success was defined as "none" or "mild" pain during treatment. Kruskal-Wallis test was used to compare pain categories in three groups of interventions for each mandibular molar. RESULTS: IANB with a supplemented buccal infiltration provided more success than IANB alone or IANB plus lingual infiltration, in first molars (P = .019). There were no significant differences between the three injection techniques in second molars (P = .795). CONCLUSIONS: Adding a supplemental buccal infiltration to a standard IANB was more successful in providing pain-free treatment for patients experiencing irreversible pulpitis in mandibular first molars.

Evaluation of Secondary Thermal Hyperalgesia Resulting from Pulpal Inflammation in Patients with Symptomatic Irreversible Pulpitis.

INTRODUCTION: Inflammation can lead to hyperalgesia and allodynia by activation or sensitization of peripheral and central nervous system neurons. This study aimed to assess the occurrence of secondary thermal hyperalgesia in patients with symptomatic irreversible pulpitis (SIP). METHODS: The cold sensitivity test (visual analog scale) was performed for the tooth with SIP, its adjacent sound tooth, the same sound tooth in the opposite jaw, and the contralateral sound tooth in the opposite quadrant of the same jaw. Next, the tooth with SIP underwent root canal treatment, and 3 weeks later, after complete elimination of pain, the teeth underwent cold sensitivity testing again. RESULTS: A total of 64 patients, including 41 women and 23 men 18-65 years old, were evaluated in this study. The response to the cold sensitivity test significantly decreased in the tooth with SIP (P < .001), its adjacent sound tooth (P < .001), and the same sound tooth in the opposite jaw (P = .004) but not in the contralateral sound tooth in the opposite quadrant of the same jaw (P = .45) after endodontic treatment. No significant difference was noted between men and women in the groups (P > .05). CONCLUSIONS: Hypersensitivity to cold test due to pulpal inflammation can also result in exaggerated response of the adjacent sound tooth and the same tooth in the opposite jaw to cold sensitivity test; these observations can be explained by the central and peripheral sensitization mechanisms.

How Does Voxel Size of Cone-beam Computed Tomography Effect Accurate Detection of Root Strip Perforations.

Introduction: Our study aimed to assess the diagnostic accuracy of different voxel sizes for cone-beam computed tomography (CBCT) when detecting strip perforations of variable sizes. We used 0.2 and 0.3 mm3 voxel for detecting root strip perforations. Methods and Materials: This was an in vitro study conducted on 155 extracted humans' mandibular first molars. The teeth were randomly divided into five groups (n=31). Perforation were not induced in the control group. In the remaining four groups, strip perforations of 0.5, 1, 1.5, and 2 mm diameters were created in the mesiolingual canal using #3 Gates Glidden drills. The CBCT scans were taken first with a 12×9 cm field of view (FOV), 90 kVp, 4 mA, and 0.2 mm3 voxel size for 24 sec and then with a 12×9 cm FOV, 90 kVp, 2 mA, and 0.3 mm3 voxel size for another 24 sec. Two observers evaluated the images and reported the largest diameter of perforations. The results were compared with the gold standard values (determined by an electronic digital caliper) using statistical methods, including the kappa coefficient and generalized estimating equation (P<0.05). Results: Based on the findings of our study, the inter-observer agreement ranged from 58-100%, while the intra-observer agreement was reported to be around 100%. The difference in accuracy between 0.2 and 0.3 mm3 voxel sizes was not statistically significant (P>0.05). In addition, the accuracy of detecting different perforation sizes in the CBCT did not follow a specific pattern. Conclusion: This in vitro study showed that CBCT is a reliable diagnostic tool, and even in lower dosages of 0.3 mm3 voxel size, image resolution and diagnostic accuracy was not affected. Moreover, smaller root perforations could be detected as accurately as larger ones with CBCT.