Augmented Reality Head-Mounted Device and Dynamic Navigation System for Postremoval in Maxillary Molars.

INTRODUCTION: This study evaluates the feasibility of an augmented reality (AR) head-mounted device (HMD) displaying a dynamic navigation system (DNS) in the surgical site for fiber postremoval in maxillary molars and compares it to the DNS technique. METHODS: Fifty maxillary first molars were divided into 2 groups: AR HMD + DNS (n = 25) and DNS (n = 25). The palatal canal was restored with RelyX fiber post (3M ESPE) luted with RelyX Unicem (3M ESPE). A core buildup was performed using Paracore (Coltene/Whaledent). Cone beam computed tomography (CBCT) scans were taken before and after postremoval. The drilling trajectory and depth were planned under X-guide software (X-Nav Technologies, Lansdale, PA). For the AR HMD + DNS group, the AR HMD (Microsoft HoloLens 2) displayed the DNS in the surgical site. The three dimensional (3D) deviations (Global coronal deviation [GCD] and global apical deviation [GAD]) and angular deflection (AD) were calculated. The number of mishaps and operating time were recorded. RESULTS: Fiber post was removed from all samples (50/50). The AR HMD + DNS was more accurate than DNS, showing significantly lower GCD and GAD deviations and AD (P < .05). No mishap was detected. The AR HMD + DNS was as efficient in time as DNS (P > .05). CONCLUSIONS: Within the limitations of this in vitro study, the AR HMD can safely display DNS in the surgical site for fiber post-removal in maxillary molars. AR HMD improved the DNS accuracy. Both AR HMD + DNS and DNS were time-efficient for fiber postremoval in maxillary molars.

Clinical Investigation of Bacteriome in Primary Endodontic Infections With Apical Periodontitis Using High-Throughput Sequencing Analysis.

INTRODUCTION: This study characterized the bacteriome in primary endodontic infection (PEI) with apical periodontitis (AP), identified core and rare bacteriome species and community diversity metrics, and analyzed the relationship between the bacteriome composition, diversity and features, and patient variables. METHODS: Twenty-seven patients with PEI and AP were sampled. The DNA was extracted and quantified using quantitative polymerase chain reaction. Raw V3-V4 amplicon sequencing data were processed with the DADA2 pipeline to generate amplicon sequence variants, and taxonomic assignment of the amplicon sequence variants up to the species level was done against the Human Oral Microbiome Database. Core bacteriome and differential abundance analyses were performed using ANCOM. Alpha diversity was determined using Chao1, Shannon, and Simpson indexes. LeFse analysis was used to identify abundant taxa. Sparse Estimation of Correlations among Microbiomes analysis estimated linear and nonlinear relationships among bacteria. RESULTS: Of 27, 24 root canal samples were analyzed, and 3 root canal sampling were filtered out with a low read count. The bacterial phyla with top mean relative abundance were Bacteroidetes, Firmicutes, Synergistetes, Fusobacteria, and Actinobacteria. A total of 113 genera and 215 species were identified. The samples were gathered into 3 clusters. LefSe analysis identified differences in abundant taxa between distinct age, gender, symptomatology, and lesion size groups. Sparse Estimation of Correlations among Microbiomes distance analysis indicated Slackia exigua as the node with the highest degree. CONCLUSIONS: The bacteriome in PEI with AP among the patients in this study was complex and displayed high microbial heterogeneity. Moreover, age, gender, symptomatology, and lesion size were associated with differences in bacteriome features in PEI with AP.

Comparison of the Accuracy and Efficiency of Two Dynamic Navigation System Workflow for Fiber-post Removal: Small versus Large Field-of-view Registration Workflows.

INTRODUCTION: This study investigates the feasibility of a dynamic navigation system (DNS) small field of view workflow (DNS-SFOVw) for fiber-post removal and compares its accuracy and efficiency to the conventional large field of view workflow (DNS-LFOVw). METHODS: Fifty-six extracted human maxillary molars were divided into DNS-SFOVw (n = 28) and DNS-LFOVw (n = 28). The palatal canal was restored with an intraradicular RelyX fiber post and luted with RelyX Unicem; a core buildup was used. Teeth were mounted in a 3D-printed surgical jaw. A preoperative cone-beam computed tomography (CBCT) scan was taken with a 40 × 40 mm FOV for the DNS-SFOVw and a single arch CBCT scan for the DNS-LFOVw. The drilling entry point, trajectory, angle, and depth were planned in the X-guide software. The DNS registration method for the DNS-SFOVw was virtual-based registration on teeth, and the marker point-based method was used for the DNS-LFOVw. The fiber posts were drilled out under DNS guidance. A postoperative CBCT scan was taken. Three-dimensional deviations, angular deflection, number of mishaps, registration, and total operation time were calculated. RESULTS: The DNS-SFOVw was as accurate as DNS-LFOVw (P > .05). The DNS-LFOVw registration time was less than DNS-SFOVw (P < .05). There was no difference in the number of mishaps (P > .05). Both DNS-SFOVw and DNS-LFOVw were time-efficient, with DNS-LFOVw taking less total operational time (P < .05). CONCLUSION: Within the limitations of this in-vitro study, the DNS-SFOVw was as accurate as the DNS-LFOVw for fiberpost removal. Both DNS-LFOVw and DNS-SFOVw were time-efficient in removing fiber-posts.

Real-Time Three-dimensional Dynamic Navigation for Post Space Preparation in Root Canal-Treated Teeth: An In vitro Study.

INTRODUCTION: The aim of this study was to investigate the feasibility of a real-time three-dimensional dynamic navigation system (3D-DNS) for post space preparation (PSP) in root canal-treated teeth and to compare the accuracy and efficiency of 3D-DNS to freehand (FH) for PSP. METHODS: Fifty-four maxillary molars were divided into two groups: 3D-DNS (n = 27) and FH group (n = 27). Cone beam computed tomography (CBCT) scans were taken preoperatively and postoperatively. The drilling path for the PSP was virtually planned in the preoperative CBCT scan in the X-guide software (X-Nav Technologies, Lansdale, PA). For the 3D-DNS group, the PSP drilling was conducted under dynamic navigation. The 3D deviations and angular deflections were calculated. The residual dentin thickness (RDT) was determined after PSP. The operation time and the total number of mishaps were recorded. Shapiro-Wilk, t-test or Mann-Whitney rank sum, weighted Cohen's kappa, and Fisher exact tests were used (P < .05). RESULTS: The PSP was completed in all samples (54/54). The 3D-DNS was more accurate than the FH, with significantly fewer 3D deviations and angular deflections (all, P < .05). The 3D-DNS required less operating time than the FH (P < .05). For the 3D-DNS, no teeth had RDT < 1 mm, whereas 6/27 in the FH showed RDT < 1 mm after the PSP. There was no difference in the total number of mishaps (P > .05). CONCLUSION: Within the limitations of this in vitro study, the 3D-DNS is feasible for PSP. The 3D-DNS improved the accuracy and efficiency of PSP. The dynamic navigation system can potentially become a safe and reliable technology for PSP.

Piezoelectric Device and Dynamic Navigation System Integration for Bone Window-Guided Surgery.

INTRODUCTION: This study investigates the feasibility of integrating a piezoelectric device (PIEZO) into a dynamic navigation system (DNS) for bone-window guided surgery. It compares the accuracy and efficiency of PIEZO + DNS to PIEZO + Freehand (FH) procedure for bone-window cutting and root-end resection (RER). METHODS: Forty-eight mandibular molars of 3D-printed surgical jaw models were divided into two groups: PIEZO + DNS (n = 24) and PIEZO + FH (n = 24). Cone-beam computed tomography scans were taken before and after the procedure. The procedure was virtually planned on X-guide software. The bone-window cutting and RER were conducted with a PIEZO under dynamic navigation in the PIEZO + DNS group and using the dental operating microscope in the PIEZO + FH group. The 2D- and 3D-accuracy deviations and angular deflection were measured for the bone window cut. The root length resected and resection angle were calculated. The bone window cut, RER, total operating time, and number of mishaps were recorded. RESULTS: PIEZO + DNS was more accurate than PIEZO + FH for bone-window cutting, showing fewer 2D and 3D deviations and less angular deflection (P < .05). The resection angle was lower in the PIEZO + DNS (P < .05). The bone-window cut and total operating time were significantly reduced using a DNS (P < .05). There was no difference in the number of mishaps (P > .05). CONCLUSIONS: Within the limitations of this in vitro study, the integration of a PIEZO into a DNS is feasible for bone-window guided surgery. The DNS improved the accuracy and efficiency of bone-window cutting.

Augmented Reality and 3-Dimensional Dynamic Navigation System Integration for Osteotomy and Root-end Resection.

INTRODUCTION: Augmented reality (AR) superimposes high-definition computer-generated virtual content onto the existing environment, providing users with an enhanced perception of reality. This study investigates the feasibility of integrating an AR head-mounted device into a 3-dimensional dynamic navigation system (3D-DNS) for osteotomy and root-end resection (RER). It compares the accuracy and efficiency of AR + 3D-DNS to 3D-DNS for osteotomy and RER. METHODS: Seventy-two tooth roots of 3D-printed surgical jaw models were divided into two groups: AR + 3D-DNS (n = 36) and 3D-DNS (n = 36). Cone-beam computed tomography scans were taken pre and postoperatively. The osteotomy and RER were virtually planned on X-guide software and delivered under 3D-DNS guidance. For the AR + 3D-DNS group, an AR head-mounted device (Microsoft HoloLens 2) was integrated into the 3D-DNS. The 2D- and 3D-deviations were calculated. The osteotomy and RER time and the number of procedural mishaps were recorded. RESULTS: Osteotomy and RER were completed in all samples (72/72). AR + 3D-DNS was more accurate than 3D-DNS, showing lower 2D- and 3D-deviation values (P < .05). The AR + 3D-DNS was more efficient in time than 3D-DNS (P < .05). There was no significant difference in the number of mishaps (P > .05). CONCLUSIONS: Within the limitations of this in vitro study, the integration of an AR head-mounted device to 3D-DNS is feasible for osteotomy and RER. AR improved the accuracy and time efficiency of 3D-DNS in osteotomy and RER. Head-mounted AR has the potential to be safely and reliably integrated into 3D-DNS for endodontic microsurgery.

Efficacy of GentleWave System and Passive Ultrasonic Irrigation with Minimally Invasive and Conventional Instrumentation Technique against Enterococcus faecalis Lipoteichoic Acid in Infected Root Canals.

INTRODUCTION: This study evaluated the effectiveness of the GentleWave System (GWS; Sonendo, Laguna Hills, CA) and passive ultrasonic irrigation (PUI) in removing Enterococcus faecalis lipoteichoic acid (LTA) from infected root canals with a minimally invasive technique (MIT) and the conventional instrumentation technique (CIT). METHODS: Sixty extracted human maxillary first premolars were included. All teeth were dentin pretreated and inoculated with LTA prepared from E. faecalis. First, 12 teeth were cryogenically ground to investigate the viability of recovering intraradicular E. faecalis LTA. Afterward, 48 teeth were randomly divided into the following groups: GWS + MIT, GWS + CIT, PUI + MIT, and GWS + CIT (all n = 12). Teeth were instrumented with a Vortex Blue (Dentsply Sirona, Ballaigues, Switzerland) rotary file size 15/.04 for MIT and 35/.04 for CIT. Samples were collected before and after a root canal procedure with sterile/apyrogenic paper points and after cryogenically ground for intraradicular LTA analysis. LTA was quantified with an LTA enzyme-linked immunosorbent assay kit. RESULTS: E. faecalis LTA was recovered from 100% of the samples (48/48) before the root canal procedure. GWS + MIT and GWS + CIT were the most effective protocols against E. faecalis LTA, with no difference between them (P > .05). PUI + CIT was more effective than PUI + MIT (P < .05) but less effective than GWS + MIT and GWS + CIT (P < .05). The GWS groups showed more root canals with undetected E. faecalis LTA after treatment than all groups tested. CONCLUSIONS: GWS + MIT and GWS + CIT were the most effective protocols against E. faecalis LTA in infected root canals.

Real-time 3-dimensional Dynamic Navigation System in Endodontic Microsurgery: A Cadaver Study.

INTRODUCTION: This study evaluated the accuracy and efficiency of the 3-dimensional dynamic navigation system (3D-DNS) to perform minimally invasive osteotomy (MIO) and root end resection (RER) in endodontic microsurgery (EMS) and investigated the viability of root end cavity preparation (RECP) and root end fill (REF) in MIO. METHODS: Forty-eight tooth roots were divided in cadaver heads into 2 groups: 3D-DNS (n = 24) and freehand (n = 24). Cone-beam computed tomographic scans were taken before and after surgery. First, virtual 3D-DNS accuracy was verified using 3 outcome measures: 2-dimensional and 3-dimensional virtual deviations and angular deflection. Second, the accuracy of 3D-DNS for performing MIO was investigated in 2 outcome measures: osteotomy size and volume. Third, the 3D-DNS accuracy was determined for RER in 3 outcomes: resected root length, root length after resection, and resection angle. The viability of RECP and REF was investigated and REF depth and volume measured as well, and procedural time and the number of mishaps were recorded. RESULTS: Two- and 3-dimensional virtual deviations and the angular deflection were lower in the 3D-DNS group than the freehand group (P < .05). Osteotomy height, length, and volume were all reduced when using 3D-DNS (P < .05). The resection angle was lower for 3D-DNS (P < .05). RECP and REF were completed in 100% of the roots. The REF depth achieved was ∼3 mm. Osteotomy time, RER time, and the total procedure time were all significantly shortened using 3D-DNS (P < .05). CONCLUSIONS: 3D-DNS enabled our surgeon to perform accurate and efficient EMS with minimally invasive osteotomy and RER. The surgeon was also able to conduct RECP with adequate REF in minimally invasive osteotomy performed using 3D-DNS guidance.

Comparison of GentleWave system and passive ultrasonic irrigation with minimally invasive and conventional instrumentation against LPS in infected root canals.

This study compared the effectiveness of GentleWave system (GWS) and passive ultrasonic irrigation (PUI) in removing lipopolysaccharides (LPS) from infected root canals after minimally invasive (MIT) and conventional instrumentation (CIT) techniques. Sixty first premolars with two roots were inoculated with fluorescent LPS conjugate (Alexa Fluor 594). Of those, twelve were dentin pretreated, inoculated with fluorescent LPS conjugate, and submitted to confocal laser scanning microscopy (CLSM) to validate the LPS-infection model. Forty-eight teeth were randomly divided into treatment groups: GWS + MIT, GWS + CIT, PUI + MIT, and PUI + CIT (all, n = 12). Teeth were instrumented with Vortex Blue rotary file size 15/0.04 for MIT and 35/0.04 for CIT. Samples were collected before (s1) and after a root canal procedure (s2) and after cryogenically ground the teeth (s3) for intraradicular LPS analysis. LPS were quantified with LAL assay (KQCL test). GWS + MIT and GWS + CIT were the most effective protocols against LPS, with no difference between them (p > 0.05). PUI + CIT was more effective than PUI + MIT (p < 0.05) but less effective than GWS + MIT and GWS + CIT. GWS was the most effective protocol against LPS in infected root canals using MIT and CIT techniques.

A Cross-sectional Survey on the Impact of Coronavirus Disease 2019 on the Clinical Practice of Endodontists across the United States.

This survey investigated the effect of the coronavirus disease 2019 (COVID-19) pandemic on the clinical practice of endodontics among the American Association of Endodontists (AAE) members by evaluating the impact on clinical activities, patient screening, infection control measurements, potential transmission, clinical protocols, as well as psychological concerns. A descriptive, cross-sectional survey was developed to query AAE members from all 7 districts. The survey consisted of 24 questions, 8 demographic questions and 16 questions related to the COVID-19 pandemic impact on the clinical practice. A total of 454 AAE members participated in the survey. As of July 2020, most endodontists were active in front-line treatment of dental patients (82%). N95 respirator face mask was described by 83.1% of the participants as special measures beyond the regular personal protective equipment. Rubber dam isolation was recognized by the majority of the participants at some level to reduce the chance of COVID-19 cross infection. Most of the endodontist participants acknowledged trauma followed by swelling, pain, and postoperative complication to be emergencies. The majority of respondents reported being concerned about the effect of COVID-19 on their practice. No differences in worries about COVID-19 infection were related to demographics (P > .05). The majority of the endodontists are aware of the COVID-19 pandemic, are taking special precautions, and are concerned about contracting and spreading the virus. Despite the conflict between their roles as health care providers and family members with the potential risk of exposing their families, most of them remain on duty providing front-line care for dental treatment.

Aerosols Generated during Endodontic Treatment: A Special Concern during the Coronavirus Disease 2019 Pandemic.

INTRODUCTION: The aims of this study were to investigate aerosolized microorganisms generated during endodontic emergencies and nonsurgical root canal therapy (NSRCT), to assess the spread of airborne microbes, and to verify the spatial distribution of airborne microbial spread. METHODS: A total of 45 endodontic procedures were sampled, including full pulpotomy (n = 15), pulpectomy (n = 15), and NSRCT (n = 15). Samples were collected during room resting and after treatment. The passive air sampling technique using settle plates was applied. Agar plates were set at different locations in the operatory. The colony-forming unit (CFU) was counted in brain-heart infusion blood agar plates. A set of agar plates containing selective chromogenic culture media was used for the isolation and presumptive identification of target microorganisms. Fungi were investigated using Sabouraud dextrose agar. RESULTS: Pulpotomy generated the lowest mean CFU count (P < .05). There was no difference between the mean CFU counts found in pulpectomy and NSRCT (P > .05). A higher mean CFU count was found close to the patient's mouth (0.5 m) than at a 2-m distance in pulpectomy and NSRCT (P < .05). There was no difference between the mean CFU count found in front of the patient's mouth versus diagonal in pulpectomy and NSRCT (P > .05). Staphylococcus aureus (22/45, 48.8%) was the most frequent bacteria species. Longer treatment times were associated with higher CFU counts. CONCLUSIONS: Our findings indicated that pulpotomy generates less aerosolized microorganisms than pulpectomy and NSRCT. The proximity to the patient's mouth and the treatment duration were implicated in the level of contamination.

Accuracy and Efficiency of 3-dimensional Dynamic Navigation System for Removal of Fiber Post from Root Canal-Treated Teeth.

INTRODUCTION: The purpose of this study was to investigate the accuracy and efficiency of the 3-dimensional dynamic navigation system (DNS) compared with the freehand technique (FH) when removing fiber posts from root canal-treated teeth. METHODS: Twenty-six maxillary teeth were included. Teeth were root canal treated and restored with Parapost Taper Lux (Coltene/Whaledent, Altstätten, Switzerland) luted with RelyX Unicem (3M ESPE, St Paul, MN). A core buildup was then performed using Paracore (Coltene/Whaledent). Teeth were mounted in tissue-denuded cadaver maxillae. Teeth were divided into 2 groups: the DNS group (n = 13) and the FH group (n = 13). Cone-beam computed tomographic scans were taken pre- and postoperatively. The drilling path and depth were planned virtually using X-guide software (X-Nav Technologies, Lansdale, PA) in both groups. For the DNS group, drilling was guided with X-Nav software and the FH group under a dental operating microscope. Global coronal and apical deviations, angular deflection, operation time, and the number of mishaps were compared between the groups to determine the accuracy and efficiency. The 3-dimensional volume (mm3) of all teeth was calculated before and after post removal using the Mimics Innovation Suite (Materialise NV, Leuven, Belgium). The Shapiro-Wilk, 1-way analysis of variance, and Fisher exact tests were used (P < .05). RESULTS: The DNS group showed significantly less global coronal and apical deviations and angular deflection than the FH group (P < .05). DNS required less operation time than FH. Moreover, the DNS technique had significantly less volumetric loss of tooth structure than the FH technique (P < .05). CONCLUSIONS: The DNS was more accurate and efficient in removing fiber posts from root canal-treated teeth than the FH technique.