The extended finite element method in endodontics: A scoping review and future directions for cyclic fatigue testing of nickel-titanium instruments.

OBJECTIVES: The present study reviews the current literature regarding the utilization of the extended finite element method (XFEM) in clinical and experimental endodontic studies and the suitability of XFEM in the assessment of cyclic fatigue in rotary endodontic nickel-titanium (NiTi) instruments. MATERIAL AND METHODS: An electronic literature search was conducted using the appropriate search terms, and the titles and abstracts were screened for relevance. The search yielded 13 hits after duplicates were removed, and four studies met the inclusion criteria for review. RESULTS: No studies to date have utilized XFEM to study cyclic fatigue or crack propagation in rotary endodontic NiTi instruments. Challenges such as modelling material inputs and fatigue criteria could explain the lack of utilization of XFEM in the analysis of mechanical behavior in NiTi instruments. CONCLUSIONS: The review showed that XFEM was seldom employed in endodontic literature. Recent work suggests potential promise in using XFEM for modelling NiTi structures.

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.

Perspectives of oral health therapists on the barriers to oral care provision in nursing homes in Singapore: A qualitative analysis.

INTRODUCTION: Oral health therapists (OHTs) are a valuable resource for increasing access to dental care for the frail elderly in nursing homes (NHs). However, OHTs face several barriers and their skill-set continues to be under-utilized. AIMS: To evaluate the perceptions of OHTs regarding the barriers towards oral care provision for the elderly residents in NHs. METHODOLOGY: Semi-structured interviews were conducted with 11 OHTs to discuss the factors that may hinder them from providing oral health services in NHs. An inductive thematic analysis directed by the grounded theory approach was performed. RESULTS: Four major themes emerged: (i) lack of opportunity, (ii) lack of adequate education and training, (iii) limited work scope and registration status, and (iv) lack of adequate financial remuneration and adequate equipment. OHTs also raised the lack of awareness among OHTs and the various stakeholders, of how the skill-set of OHTs may be relevant for oral care provision in NHs. CONCLUSION: Findings revealed underlying educational and regulatory barriers which need to be addressed in tandem. Addressing these barriers can be impactful in informing future strategies for the greater utilization of the skill-set of OHTs in Singapore.

Singapore dentists' attitudes toward dental care provision for older adults with disabilities.

OBJECTIVES: This study aimed to assess dentists' attitudes toward providing dental care for older adults with disabilities in Singapore and the factors influencing their willingness to provide care. BACKGROUND: Dentists face a rapidly ageing patient demographic. Practitioner unwillingness to circumvent the attending challenges of care provision prevents older adults from accessing the dental care necessary for better oral and systemic health. Previous studies have reported on dentists' attitudes toward caring for older adults with disabilities; however, these are mostly limited to dependent older adults and exclude frail, community-dwelling older persons. METHODS: A cross-sectional study was conducted in 2020 using a self-administered questionnaire. Quantitative data analysis was presented in the form of descriptive statistics, followed by bivariate analyses. RESULTS: There were 193 respondents, a response rate of under 9%. Dentists were less willing, confident and involved in the care of older adults with disabilities as the individual's severity of impairments increased. Less than half of respondents were willing to treat individuals with severe disabilities in cooperation (23.3%), swallowing (30.6%), mobility (33.7%) and communication (45.1%). Dentists with training in geriatric dentistry were more willing to provide care. However, younger dentists, general dental practitioners, private practitioners and public sector dentists had specific restraining and driving forces, which further modulated their willingness to provide care. CONCLUSIONS: The current areas of training needs among Singapore dentists are in severe impairments of swallowing, communication, cooperation and mobility. Further geriatric dentistry training may effectively increase dentists' willingness to provide care; however, additional specific targeted interventions are also needed.

Knowledge, Attitudes and Performance of Iranian Endodontists to Patients with Kidney Diseases.

OBJECTIVE: The high prevalence of chronic kidney disease in the community, especially in older patients, makes their management an important aspect of clinical practice. The aim of this study was to evaluate the knowledge attitudes and performance of Iranian endodontists regarding patients with chronic kidney disease (CKD). METHODS: This cross-sectional, descriptive-analytical study involved 100 Iranian endodontists (41 M, 59 F), who completed questionnaires with 21 items on CKD. Responses were analyzed by SPSS, using Chi-square or Fisher's exact tests. RESULTS: Overall levels of knowledge were rated as optimal in 55% of subjects, while attitudes to care were favourable in 83%. This cohort of specialist clinicians had strong scores for optimal attitude and performance. Awareness of issues around prescribed analgesics, antibiotic cover, bleeding risk and hypertension was high. Proximity to specialist training (younger specialists, and less years in practice) and female gender were associated with significantly higher scores across the three domains measured. CONCLUSION: Most specialists were aware of requirements for safe care of dental patients with CKD. Continuing professional education should target older clinicians who may have had less exposure to formal training in this topic during their clinical training. (EEJ-2022-04-059).

Does luminosity and smear layer influence 810 nm laser energy transmission through human dentine?

PURPOSE: The aim of this study was to evaluate the influence of luminosity values and smear layer on transmission characteristics of 810 nm near infrared laser energy through dentine, using extracted human teeth. METHODS: A total of 200 teeth treated with endodontic medicaments to cause discolouration (Ledermix, Doxypaste or Odontopaste) were selected, to give a range of values for tooth shade (luminosity values). Sectioned teeth had smear layer created or removed. Near-infrared laser energy transmission was assessed using an 810 nm diode laser (90 mW, CW mode) with the tip placed at 2 mm and 4 mm from the external root surface, and a laser power metre. RESULTS: Both tooth shade and smear layer had independent attenuating effects. Transmission of laser energy was significantly lower in teeth with darker shades. There was a strong positive correlation between relative luminosity (lighter tooth colour) and transmitted laser power (r = 0.9271 for the Spearman rank correlation, P = 0.0022). When a smear layer was present, this significantly reduced the transmission of laser energy through the sample, compared to when no smear layer was present. CONCLUSION: The results of this laboratory study highlight the attenuating influence of a darker tooth shade and the presence of smear layer on the transmission of 810 nm light when directed onto the surface of human dentine. Such effects may be relevant to photo biomodulation, Photodynamic Therapy and other dental laser treatments.

Oral parafunction and bruxism in Rett syndrome and associated factors: An observational study.

OBJECTIVES: To explore patterns of parafunction, and bruxism, and its relationships with genotype and snoring in individuals with Rett syndrome (RTT). METHODS: Retrospective observational data of those with confirmed MECP2 mutations in the InterRett database (n = 216) were used to investigate experience of parafunctional habits, and bruxism and their relationships with genotype and snoring using multivariable linear regression. RESULTS: The prevalence of parafunction was 98.2%. Bruxism was reported (66.2%) with the patterns mostly both diurnal and nocturnal (44.1%) and exclusively diurnal (42.7%). Compared to individuals with C-terminal deletion, individuals with p.Arg106Trp mutations were less likely to have bruxism reported (aOR = 0.15; 95% CI 0.02-0.98, p = 0.05) and those with p.Arg168* mutation were more likely to have frequent bruxism than none or occasional bruxism reported (aROR 3.4; 95% CI 1.1-10.7 p = 0.04). The relative odds of having nocturnal bruxism constantly, compared to none/occasionally, were higher among those 'always' snoring (aROR 6.24; 95% CI 2.1-18.2, p = 0.001) than those with no snoring. CONCLUSIONS: There appeared to be genotypic association with bruxism in p.Arg168* and p.Arg106Trp mutations and association between nocturnal bruxism and frequent snoring in an international sample of individuals with RTT. Clinical significance of the high prevalence of bruxism should be highlighted in relation to difficulty communicating pain and increased dental treatment need in RTT.

Development and Reversal of Discolouration in Roots Filled with Ledermix or Doxymix Pastes Stored in the Dark for Three Months then Daylight for Twenty Four Months.

OBJECTIVE: To explore the long-term effects on discolouration by demeclocycline HCl (Ledermix, LED) or doxycycline hyclate (Doxymix, DOX) pastes placed in extracted human teeth over a 27-month period under different storage conditions. METHODS: The canals in 38 teeth were prepared carefully, to minimize exposure to contamination from irrigants, then either LED (Lederle Pharmaceuticals, Germany) or DOX (Ozdent, Australia) were placed. Samples were stored in the dark for 3 months followed by daylight for 24 months. The storage conditions varied as follows: Group 1: Open access, dry storage (OD); Group 2: Closed access, dry storage (CD); Group 3: Open access, wet storage (OW); Group 4: Closed access, wet storage (n=4 for each material). Additional teeth were used as controls: Polyethylene glycol only in a closed canal; and saline only irrigation with LED paste in a closed canal. Standardised digital photographs were taken over 27 months and evaluated for changes in luminosity. RESULTS: Darkening of tooth structure occurred in all LED groups and in the two DOX groups that were stored wet, during exposure to light, with a faster rate with LED. The most rapid staining occurred with LED in moist conditions with an open access cavity. The least staining occurred with DOX in samples stored dry. With prolonged exposure to light, a reversal in staining occurred with DOX at 3 months and LED at 9 months. CONCLUSION: Staining of tooth structure is influenced by the choice of medicament, and by exposure to moisture and air. Light has a bimodal effect, first driving staining, but later reversing it. This can be explained by different wavelengths of light causing photodegradation and photo-oxidation of tetracyclines and their complexes with tooth mineral.

Evaluation of the diffusion of triamcinolone and demeclocycline through the dentinal tubules and apical foramen: A mass spectrometry study.

Aim: The aim of this study was to investigate the diffusion of triamcinolone and demeclocycline from an endodontic paste when used unmodified, versus when combined in equal parts with a calcium hydroxide paste, in terms of diffusion through the dentinal tubules versus through the apical foramen. Methodology: Medicaments were placed in endodontically prepared roots that were kept in vials of Milli-Q water. The five experimental groups in the study were (1) control - no medicament, (2) medicament containing triamcinolone and demeclocycline (T&D) and occluded apex, (3) T&D paste and patent apex, (4) T&D + calcium hydroxide (Ca(OH)2) occluded apex, and (5) T&D + Ca(OH)2 and patent apex. The triamcinolone and demeclocycline concentrations were measured with solid-phase extraction and ultra-high performance liquid chromatography-mass spectrometry, after 1, 3, 8, and 24 h, and after 1 week. Results: Most of the triamcinolone and demeclocycline diffused through the apical foramen, with sparse diffusion through the dentinal tubules. The T&D paste mixed with Ca(OH)2 in equal amounts showed greater than the expected 50% reduction in the diffusion of triamcinolone and demeclocycline from mass dilution alone (89% and 80%, respectively). Conclusions: These results stress the importance of maintaining apical patency, for allowing diffusion of active components of the drugs to target tissues in the periapical environment.

Interprofessional collaboration utilizing oral health therapists in nursing homes: Perceptions of oral health therapists and nursing home staff in Singapore.

INTRODUCTION: Oral health therapists (OHTs) have the potential to increase the access to oral care for elderly residents in nursing homes (NHs). AIMS: To evaluate the perceptions of NH staff and OHTs regarding the barriers and enablers toward oral care provision for elderly NH residents, and their perceptions toward interprofessional collaboration through the utilization of OHTs in NHs. METHODOLOGY: Electronic surveys were completed by 231 direct care and 15 managerial staff from 15 NHs, and 103 OHTs. Factors influencing oral care provision, and aspects of awareness, capabilities, and willingness/interest toward collaboration were evaluated. RESULTS: The OHTs and NH staff reported mutually positive responses toward interprofessional collaboration. The most frequently reported barriers by the NH staff were the lack of regular support from dental health professionals and inadequate knowledge and skills. The OHTs expressed willingness and competence in assisting the NH staff, but lacked regulatory and educational support. CONCLUSION: OHTs have the potential to address the barriers faced by the NH staff, if adequately supported through policy and education. Oral health promotion in intermediate and long-term care sectors should take into account this potential for interprofessional collaboration through greater utilization of the skill-set of OHTs.

Enablers and barriers in dental attendance in Rett syndrome: an international observational study.

AIMS: Intellectual and developmental disabilities are heterogeneous in aetiology and presentation, and one cannot make assumptions about the oral health barriers of those with Rett syndrome (RTT) based on findings from generic studies. This study investigated caregivers' perceptions regarding access to dental care for those with (RTT), and associations of dental treatments received by those with RTT with their caregivers' perceived value of oral health and perception of their own as well as their daughter's dental anxiety. METHODS AND RESULTS: Retrospective observational data of a subset of individuals with confirmed MECP2 mutations in the InterRett database (n = 216) were used to explore caregiver-related factors and their relationships with longitudinal data on dental service utilisation, using negative binomial regression. The main reported barriers to dental care access for individuals with RTT were primarily dentist-related in nature, regardless of dental service history. Those with reported dental nonattendance were of older age. Increasing levels of caregiver-reported dental fear were associated with less frequent dental check-ups or for any appointments for affected individuals. CONCLUSIONS: Dentist-related barriers and caregiver-reported anxiety may both adversely affect dental attendance for those with RTT. Future research should explore caregivers' beliefs and oral health literacy.

Oral health education and promotion in special needs children: Systematic review and meta-analysis.

OBJECTIVE: To review the effectiveness of oral health education and oral health promotion interventions for children and adolescents with intellectual and developmental disabilities (IDD), in ensuring optimal gingival health, caries experience and oral health-related quality of life, compared to no interventions or alternative interventions. METHODS: A systematic review was conducted to identify published studies from four databases (Medline, PsycINFO, CINAHL and ERIC). Randomised or quasi-randomised controlled trials were included. Two independent reviewers performed risk of bias and qualitative analysis. Meta-analysis was performed as appropriate. RESULTS: Eight treatment comparisons were identified. There was low certainty evidence that fluoride interventions provided long-term reductions in caries in those with IDD; and there was some evidence that chlorhexidine albeit with low certainty provided short-term and long-term reductions in plaque and gingivitis. There was moderate certainty evidence for short-term reductions in dental plaque from the use of modified toothbrushes, but not compelling evidence for powered toothbrushes. CONCLUSIONS: Most studies provided a low quality of evidence, and so any adaptations made to oral health practices of individuals with IDD need to consider their individual needs. PROSPERO registration: CRD42019145784.

Comparison of Canal Transportation, Separation Rate, and Preparation Time between One Shape and Neoniti (Neolix): An In Vitro CBCT Study.

PURPOSE: This in vitro study compared root canal preparation in curved mesiobuccal canals of molar teeth using either the One Shape™ or the Neoniti (Neolix) rotary NiTi single-file systems, assessing canal transportation, instrument separation and time required for preparation. Methods. Extracted maxillary and mandibular human molar teeth with mesiobuccal canals having apical angles of curvature between 25 and 35o were selected and embedded in acrylic resin blocks, and an initial CBCT was taken. The teeth were divided into two equal groups (n = 20), and the canals were cleaned and shaped using either Neoniti™ or One Shape™ engine-driven NiTi rotary files. Each individual instrument was used to prepare 5 canals. The time required for the preparation of each canal was recorded. Postpreparation CBCT scans were taken and used to determine the extent of canal transportation at levels of 2, 4, 6, and 8 mm from the apex. The Kolmogorov-Smirnov test for normality was applied, and then, datasets were compared using independent t-tests, with a threshold of P < 0.05. RESULTS: Neoniti rotary files caused significantly less canal transportation of the curved canals (P=0.0001). On the other hand, the time required for canal preparation was significantly shorter for One Shape (P=0.0001). No instrument separation was recorded in both groups. CONCLUSION: Based on these results, the Neoniti™ rotary file system is preferred because it maintains the original shape of curved root canals better than One Shape™; even though this benefit comes at the cost of an increase in preparation time in clinical practice, the better technical performance may be more important than a difference in procedural time.

Effectiveness of implant surface debridement using particle beams at differing air pressures.

Because implant surface decontamination is challenging, air powder abrasive systems have been suggested as an alternative debridement method. This in vitro study investigated the effectiveness of different powder formulations and air pressures in cleaning implant surfaces and the extent of surface damage. A validated ink model of implant biofilm was used. Sterile 4.1 × 10 mm Grade 4 titanium implants were coated in a blue indelible ink to form a uniform, visually detectable biofilm-like layer over the implant threads and mounted into a bone replica material with bony defects to approximate peri-implantitis. Air powder abrasive treatments were undertaken using glycine, sodium bicarbonate, or calcium carbonate powder at air pressures of 25, 35, 45, and 55 psi. Digital macro photographs of the threads were stitched to give composite images of the threads, so the amount of ink remaining could be quantified as the residual area and expressed as a percentage. Implant surfaces were also examined with scanning electron microscopy to grade the surface changes. No treatment cleaned all the surface of the threads. The powders were ranked in order of decreasing effectiveness and decreasing surface change into the same sequence of calcium carbonate followed by sodium bicarbonate followed by glycine. Higher air pressure improved cleaning and increased surface change, with a plateau effect evident. All powders caused some level of surface alteration, with rounding of surface projections most evident. With air powder abrasive systems, there is a trade-off between cleaning efficacy and surface damage. Using this laboratory model, sodium bicarbonate and calcium carbonate powders were the most effective for surface cleaning when used at air pressures as low as 25 psi.

Deconvolution of the particle size distribution of ProRoot MTA and MTA Angelus.

Objective Mineral trioxide aggregate (MTA) cements contain two types of particles, namely Portland cement (PC) (nominally 80% w/w) and bismuth oxide (BO) (20%). This study aims to determine the particle size distribution (PSD) of PC and BO found in MTA. Materials and methods The PSDs of ProRoot MTA (MTA-P) and MTA Angelus (MTA-A) powder were determined using laser diffraction, and compared to samples of PC (at three different particle sizes) and BO. The non-linear least squares method was used to deconvolute the PSDs into the constituents. MTA-P and MTA-A powders were also assessed with scanning electron microscopy. Results BO showed a near Gaussian distribution for particle size, with a mode distribution peak at 10.48 µm. PC samples milled to differing degrees of fineness had mode distribution peaks from 19.31 down to 4.88 µm. MTA-P had a complex PSD composed of both fine and large PC particles, with BO at an intermediate size, whereas MTA-A had only small BO particles and large PC particles. Conclusions The PSD of MTA cement products is bimodal or more complex, which has implications for understanding how particle size influences the overall properties of the material. Smaller particles may be reactive PC or unreactive radiopaque agent. Manufacturers should disclose particle size information for PC and radiopaque agents to prevent simplistic conclusions being drawn from statements of average particle size for MTA materials.

Methodologies for measuring the setting times of mineral trioxide aggregate and Portland cement products used in dentistry.

Objective The current standard used to measure setting time for Mineral Trioxide Aggregate (MTA) involves indentation testing with arbitrary weights. This study compared indentation testing against rheological measurements and assessed the influences of particle size and the inclusion of bismuth oxide on the setting time of experimental MTA and Portland cement (PC). Material and methods Two PCs (P1 and P2) of different particle sizes were produced using the same clinker. From these two PCs, two experimental MTAs (M1 and M2) were created with the addition of bismuth oxide. Particle size distributions were assessed using laser diffraction analysis. Indentation setting time tests were performed in accordance to the Gillmore needle test. Elastic modulus was assessed using a strain-controlled rheometer at 1 rad s-1 and an applied strain of 0.01%. Results P1, P2, M1 and M2 cements had median particle sizes of 6.1, 12.5, 6.5 and 13.0 µm, respectively. Using indentation testing, final setting times were ranked P1 < M1 < P2 < M2. The ranking of the final setting time corresponded with the rheological assessment of time required to reach 95% of the elastic modulus plateau. Conclusions The time to reach 95% elastic modulus plateau of 9.3 min corresponds to a time close to the point where the material can be overlaid with another restorative material to give a final restoration. The 95% plateau value for elastic modulus may be a more useful parameter for determining how the setting reaction of PC and MTA cements progress over time.

The influence of particle size and curing conditions on testing mineral trioxide aggregate cement.

Objectives: To assess the effects on curing conditions (dry versus submerged curing) and particle size on the compressive strength (CS) and flexural strength (FS) of set MTA cement. Materials and methods: Two different Portland cements were created, P1 and P2, with P1 < P2 in particle size. These were then used to create two experimental MTA products, M1 and M2, with M1 < M2 in particle size. Particle size analysis was performed according to ISO 13320. The particle size at the 90th percentile (i.e. the larger particles) was P1: 15.2 µm, P2: 29.1 µm, M1: 16.5 µm, and M2: 37.1 µm. M2 was cured exposed to air, or submerged in fluids of pH 5.0, 7.2 (PBS), or 7.5 for 1 week. CS and FS of the set cement were determined using a modified ISO 9917-1 and ISO 4049 methods, respectively. P1, P2, M1 and M2 were cured in PBS at physiological pH (7.2) and likewise tested for CS and FS. Results: Curing under dry conditions gave a significantly lower CS than when cured in PBS. There was a trend for lower FS for dry versus wet curing. However, this did not reach statistical significance. Cements with smaller particle sizes showed greater CS and FS at 1 day than those with larger particle sizes. However, this advantage was lost over the following 1-3 weeks. Conclusions: Experiments that test the properties of MTA should cure the MTA under wet conditions and at physiological pH.

Insight in the chemistry of laser-activated dental bleaching.

The use of optical radiation for the activation of bleaching products has not yet been completely elucidated. Laser light is suggested to enhance the oxidizing effect of hydrogen peroxide. Different methods of enhancing hydrogen peroxide based bleaching are possible. They can be classified into six groups: alkaline pH environment, thermal enhancement and photothermal effect, photooxidation effect and direct photobleaching, photolysis effect and photodissociation, Fenton reaction and photocatalysis, and photodynamic effect.

Effect of Photo-Fenton Bleaching on Tetracycline-stained Dentin in vitro.

AIM: Tetracycline-stained tooth structure is difficult to bleach using nightguard tray methods. The possible benefits of in-office light-accelerated bleaching systems based on the photo-Fenton reaction are of interest as possible adjunctive treatments. This study was a proof of concept for possible benefits of this approach, using dentine slabs from human tooth roots stained in a reproducible manner with the tetracycline antibiotic demeclocycline hydrochloride. MATERIALS AND METHODS: Color changes overtime in tetra-cycline stained roots from single rooted teeth treated using gel (Zoom! WhiteSpeed(®)) alone, blue LED light alone, or gel plus light in combination were tracked using standardized digital photography. Controls received no treatment. Changes in color channel data were tracked overtime, for each treatment group (N = 20 per group). RESULTS: Dentin was lighter after bleaching, with significant improvements in the dentin color for the blue channel (yellow shade) followed by the green channel and luminosity. The greatest changes occurred with gel activated by light (p < 0.0001), which was superior to effects seen with gel alone. Use of the light alone did not significantly alter shade. CONCLUSION: This proof of concept study demonstrates that bleaching using the photo-Fenton chemistry is capable of lightening tetracycline-stained dentine. Further investigation of the use of this method for treating tetracycline-stained teeth in clinical settings appears warranted. CLINICAL SIGNIFICANCE: Because tetracycline staining may respond to bleaching treatments based on the photo-Fenton reaction, systems, such as Zoom! WhiteSpeed, may have benefits as adjuncts to home bleaching for patients with tetracycline-staining.

Laser-induced agitation and cavitation from proprietary honeycomb tips for endodontic applications.

Cavitation and agitation generated by lasers in fluid-filled root canals create fluid movement and shear stresses along the root canals walls, enhancing removal of the smear layer and biofilm. When used with sodium hypochlorite and EDTA, laser activation of aqueous fluids can increase the efficiency of debridement and disinfection of root canals. However, the use of forward-firing laser fibers with such solutions poses a risk of driving fluid past the root apex, which could cause postoperative complications. The purpose of this study was to evaluate the mechanism of fluid agitation caused by a novel honeycomb tip. Glass capillary tubes filled with distilled water were used to replicate single-tooth root canals. A 980 nm pulsed diode laser was used with 200 µm diameter plain tips, tube-etched conical tips, and honeycomb tips. To record fluid movements, the tubes were backlit and imaged using a digital camera attached to a microscope. The honeycomb tips generated agitation with fluid movement directed onto the walls, while both the conventional plain fibers and the conical tips created fluid movement largely in a forward direction. The use of honeycomb tips alters the pattern of fluid agitation, and this laterally directed effect might lower the risk of fluid extrusion beyond the apex.