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Lasers in Medical Science Aug 2023This study aimed to evaluate the efficacy of Shock Wave Enhanced Emission Photoacoustic Streaming (SWEEPS) in the removal of remaining pulp tissue from the root canal...
The efficacy of a novel SWEEPS laser-activated irrigation compared to ultrasonic activation in the removal of pulp tissue from an isthmus area in the apical third of the root canal.
This study aimed to evaluate the efficacy of Shock Wave Enhanced Emission Photoacoustic Streaming (SWEEPS) in the removal of remaining pulp tissue from the root canal isthmus area in lower molars and compare it with ultrasonically activated irrigation (UAI) and conventional needle irrigation (NI). Forty-one lower molars with isthmuses between mesial canals were included in the study. The teeth were randomly distributed into experimental groups (n = 12/each) based on the final irrigation protocol (SWEEPS, UAI, or NI) and a control group (C) (n = 5). The traditional access cavity of the mesial part of each tooth was made in all samples. The mesial root canals in the experimental groups were instrumented with a Wave One Gold Primary (25/.07) file using 3% sodium hypochlorite (NaOCl) while the distal canal served as a control for the presence of pulp tissue. No treatment was performed in the C group. Sections from the isthmus region were processed for histopathology to measure the remaining pulp tissue (RPT). The results were analyzed using analysis of variance and the Kruskal-Wallis test (α = 0.05). There were no significant differences in the relative surface area of root canals and isthmus among the groups (p > 0.05). Samples in the SWEEPS group had significantly less RPT than UAI, NI, and C (p = 0.003, 0.014, 0.003, respectively). There were no significant differences between the UAI and NI (p = 0.583). SWEEPS was the most efficient in debridement of the root canal isthmus area. UAI and NI showed similar but lower efficiency.
Topics: Dental Pulp Cavity; Gold; Lasers; Root Canal Therapy; Ultrasonic Waves; Molar; Humans
PubMed: 37599293
DOI: 10.1007/s10103-023-03857-4 -
International Endodontic Journal Oct 2023To assess the influence of a flat-side design on the geometry, metallurgy, mechanical performance and shaping ability of a novel nickel-titanium rotary instrument.
AIM
To assess the influence of a flat-side design on the geometry, metallurgy, mechanical performance and shaping ability of a novel nickel-titanium rotary instrument.
METHODOLOGY
Sixty-five new 25-mm flat-side rotary instruments (size 25, taper 0.04) and their nonflat-side prototypes (n = 65) were assessed for major deformations and examined regarding macroscopic and microscopic design, determination of nickel and titanium elements ratio, measurement of phase transformation temperature and evaluation of mechanical performance parameters including time/cycles to fracture, maximum torque, angle of rotation, maximum bending and buckling strengths and cutting ability. Additionally, unprepared canal areas, volume of hard tissue debris and percentage reduction of dentine thickness were calculated for each tested instrument after preparing mesial canals of mandibular molars (n = 12), using micro-CT imaging. Statistical analyses were performed using the U-Mann-Whitney test and independent Student t-test (α = 5%).
RESULTS
The number of spirals (n = 8) and blade direction (clockwise) were similar between both flat and nonflat instruments, whilst the helical angles were equivalent (⁓25°). Flat-instruments showed inconsistencies in the homogeneity of the gold colour on the flat-side surface, blade discontinuity, and incomplete and variable S-shaped cross-sections. The titanium-to-nickel ratios were equivalent, but significant differences in the R-phase finish and austenitic start phase transformation temperatures were observed between the flat and nonflat-side instruments. The flat-side instruments demonstrated superior cutting ability compared to the nonflat instruments, as well as, significantly lower values for time to fracture, rotation to fracture and maximum torque to fracture (p < .001). No statistical difference was observed between tested instruments regarding angle of rotation (p = .437), maximum bending (p = .152) and buckling load (p = .411). Preparation protocols using flat and nonflat instruments did not show any statistically significant differences (p > .05). All flat-side instruments exhibited deformation after shaping procedures.
CONCLUSIONS
The flat-side instrument showcased enhanced cutting ability compared to its nonflat counterpart. However, it exhibited inferior performance in terms of time, rotation and maximum torque to fracture, along with distinct phase transformation temperatures. No differences were observed in the titanium-to-nickel ratios, angle of rotation, maximum bending, buckling load, preparation time, percentage of untouched canal walls, volume of hard tissue debris and percentage reduction of dentine thickness.
Topics: Humans; Nickel; Titanium; Dental Pulp Cavity; Metallurgy; Molar
PubMed: 37594701
DOI: 10.1111/iej.13960 -
Maedica Jun 2023The early eruption of the first permanent molar (FPM) favors its exposure to the risk factors for dental caries specific to the mixed dentition stage of dental...
The early eruption of the first permanent molar (FPM) favors its exposure to the risk factors for dental caries specific to the mixed dentition stage of dental development. The aim of this study was to assess the prevalence and distribution pattern of FPM dental caries and of the consequences of this pathology - caries with pulp involvement in the FPM and missing FPM (FPM extraction) in a sample of Romanian children during the mixed dentition stage. To evaluate the effect of asanas in Yoga on the IOP of practicing individuals. Eighty-seven children aged between five and 13 years, who attended a private dental clinic, were enrolled in the present study. The investigations were carried out as part of the comprehensive dental examinations. Written informed consent was obtained from one of the subjects' parents prior to his/her child's participation in this research. The collected data were statistically analyzed with STATA/MP13 software using the Chi square test. The level of significance was set at p<0.05. The prevalence of FPM dental caries was 60.9%. There were statistically significant differences (p = 0.004) in the number of FPMs affected by dental caries subject in relation to age. No statistically significant differences regarding the number of FPMs affected by dental caries subject in relation to gender were found. With respect to the distribution pattern of FPM dental caries by location at tooth level, the mesial surface had the highest prevalence (in 36.8% of all investigated subjects), followed by the occlusal surface (33.3%). The prevalence of caries with pulp involvement in the FPM was 19.5% and children in the 10-11-year age group were the most affected (55.5%). There were statistically significant differences regarding the distribution pattern of caries with pulp involvement in the FPM by age (p = 0.0001). The prevalence of FPM extraction was 6.9% and, according to dental history and examination, loss of FPM was due to caries. Among children with missing FPM, five were older than the age recommended for achieving spontaneous space closure, which indicated the need for immediate intervention. Considering the results of the present study, it can be stated that FPM dental caries represents a highly prevalent pathology during the mixed dentition stage. The findings are relevant and useful for the current clinical dental practice, emphasizing the importance of caries detection and diagnosis in developing a comprehensive dental treatment plan tailored to the specific needs of pediatric patients.
PubMed: 37588835
DOI: 10.26574/maedica.2023.18.2.246 -
Anais Da Academia Brasileira de Ciencias 2023Notosuchian crocodyliforms were major components of the South American Cretaceous biota and, for over 125 years, paleontological fieldwork in this continent recovered...
Notosuchian crocodyliforms were major components of the South American Cretaceous biota and, for over 125 years, paleontological fieldwork in this continent recovered several well-preserved fossils of these animals. They are largely recognized for terrestrial life and specialized feeding habits, frequently presenting bizarre taxa such as Comahuesuchus. A new species, Comahuesuchus bonapartei n. sp. (MUCPv 597; cast MN), is described from geological strata of Sierra Barrosa Formation (Upper Turonian) and Portezuelo Formation (Lower Coniacian) of Lake Barreales, Patagonia, Argentina. The new fossil comprises a right dentary bone that shares important and unique anatomical features with specimens of Comahuesuchus brachybuccalis, such as the presence of a well-marked shelf on the lateral surface of the bone; a flat, low, and wide mandibular symphysis; an enlarged, labiolingually compressed caniniform tooth at caudal position in the dentary; the presence of serrated mesial and distal carinae in the caniniform with a faceted labial surface, and the absence or extremely reduction in number of the postcaniniform dentition. C. bonapartei differs from C. brachybuccalis in having individual dentary alveoli, rather a dentition set in groove. Phylogenetic analyses support a sister-relationship between both species, which are well nested within notosuchians.
Topics: Animals; Phylogeny; Argentina; Lakes; Mandible; Paleontology; Fossils; Dinosaurs
PubMed: 37585972
DOI: 10.1590/0001-3765202320230179 -
Annals of Anatomy = Anatomischer... Oct 2023Osteocytes are the most abundant cell type in adult bone, and the morphological characteristics of osteocytes and their lacunae appear to influence bone mass and...
BACKGROUND
Osteocytes are the most abundant cell type in adult bone, and the morphological characteristics of osteocytes and their lacunae appear to influence bone mass and fragility. Although conventional computed tomography (CT) has contributed greatly to advances in bone morphometry, capturing details of the entire hierarchical assembly, e.g., osteocyte lacuna parameters, has been limited by the analytical performance of CT (> 1 µm resolution).
METHODS
We used high-resolution (700 nm) micro-CT to evaluate and compare the osteocyte lacuna parameters over a large scale, i.e., in a maximum of about 45,700 lacunae (average), in tibial metaphyseal cortical bones of wild-type (WT) and αKlotho-hypomorphic (kl/kl) mice, the latter a model that exhibits osteopenia and aberrant osteocytes.
RESULTS
Of osteocyte lacuna parameters, lacunar surface per lacunar volume were significantly lower and lacuna diameter were significantly larger in kl/kl mice compared to WT mice. By analysis of individual osteocyte lacunae, we found that lacunar sphericity in kl/kl mice was higher than that in WT mice, and the diameters in the major and the minor axes were respectively lower and higher in kl/kl mice, especially at the proximal site of the region of interest.
CONCLUSION
We successfully assessed osteocyte lacuna parameters on the largest scale in mice reported to date and found that the shape of osteocyte lacunae of kl/kl mice are significantly different from those of WT mice. Although the mechanisms underlying the lacunar shape differences observed are not yet clear, changes in lacunar geometry are known to affect the transitions of strains to the osteocyte microenvironment and likely local osteocyte response(s). Thus, the fact that the differences are limited to the mesial region near the primary spongiosa suggests the likelihood of site-specific anomalies in mechanosensitive effects in kl/kl osteocytes with consequent site-specific effects bone metabolism and function.
Topics: Mice; Animals; Osteocytes; X-Ray Microtomography; Bone and Bones
PubMed: 37572763
DOI: 10.1016/j.aanat.2023.152142 -
Journal of Human Evolution Sep 2023Enamel mechanical properties vary across molar crowns, but the relationship among mechanical properties, tooth function, and phylogeny are not well understood. Fifteen...
Enamel mechanical properties vary across molar crowns, but the relationship among mechanical properties, tooth function, and phylogeny are not well understood. Fifteen primate lower molars representing fourteen taxa (catarrhine, n = 13; platyrrhine, n = 1) were sectioned in the lingual-buccal plane through the mesial cusps. Gradients of enamel mechanical properties, specifically hardness and elastic modulus, were quantified using nanoindentation from inner (near the enamel-dentine junction), through middle, to outer enamel (near the outer enamel surface) at five positions (buccal lateral, buccal cuspal, occlusal middle, lingual cuspal, lingual lateral). Cuspal positions had higher mechanical property values than lateral positions. Middle enamel had higher mean hardness and elastic modulus values than inner and outer locations in all five crown positions. Functionally, the thicker-enameled buccal cusps of lower molars did not show evidence of increased resistance to failure; instead, lingual cusps-which show higher rates of fracture-had higher average mechanical property values, with no significant differences observed between sides. Preliminary phylogenetic results suggest there is relatively little phylogenetic signal in gradients of mechanical properties through the enamel or across the crown. There appears to be common mechanical property patterns across molar crowns in Catarrhini and potentially among primates more broadly. These results may allow more precise interpretations of dental biomechanics and processes resulting in mechanical failure of enamel in primates, such as wear and fracture.
Topics: Animals; Phylogeny; Tooth; Primates; Crowns; Cercopithecidae; Hardness; Dental Enamel
PubMed: 37562101
DOI: 10.1016/j.jhevol.2023.103413 -
The International Journal of... Aug 2023Implants with deficient papillae and black triangle are common findings. The treatment of these esthetic complications is considered challenging, and with limited...
Implants with deficient papillae and black triangle are common findings. The treatment of these esthetic complications is considered challenging, and with limited predictability. Therefore, the aim of the present report is to describe a novel technique for papilla augmentation (the "Iceberg" connective tissue graft [iCTG]) after extraction and interproximal bone reconstruction in the anterior region. A 35-year-old patient presented with a hopeless tooth with interproximal clinical attachment loss extending up the apical third of the adjacent tooth. Interproximal bone reconstruction was performed through alveolar ridge preservation by directly applying recombinant human platelet-derived growth factor-BB (rhPDGF-BB) to the exposed root surface of the adjacent tooth. A mixture of autogenous bone chips (obtained from the ramus) and bovine bone xenograft particles, previously mixed with the growth factor, was also used. The patient was able to come back for implant therapy only 2 years later. An incomplete regeneration of the interproximal bone was observed. Therefore, to compensate the interproximal deficiency, the iCTG approach, involving a double layer CTG with different origins, was utilized. Two small grafts from the tuberosity were sutured to the mesial and distal ends of a wider CTG harvested from the palate, aiming at gaining additional volume at the interproximal sites. The composite graft was then sutured on top of the implant platform, with the flap that was then released and closed by primary intention. After conditioning of the peri-implant tissues, the case was finalized with a satisfactory outcome. The described iCTG could be an effective approach for reconstructing peri-implant papilla following interproximal bone reconstruction.
PubMed: 37552185
DOI: 10.11607/prd.6731 -
Zootaxa Apr 2023Two new species of stream-dwelling crayfish, Cambarus lapidosus, the Stony Fork Crayfish, and Cambarus burchfielae, the Falls Crayfish, are described from the Yadkin...
Two new species of stream-dwelling crayfish, Cambarus lapidosus, the Stony Fork Crayfish, and Cambarus burchfielae, the Falls Crayfish, are described from the Yadkin River basin in western North Carolina, USA, using an integrative taxonomic approach consisting of morphological, genetic, and biogeographic data. Both species were previously considered to be members of the widely distributed Cambarus species C complex, which occurs throughout mid-Atlantic Slope river basins; however, they are in fact morphologically and genetically more similar to the Cambarus robustus species complex from interior basins in the south-central Appalachians, indicating Atlantic basin stream capture of an Interior basin faunal group has occurred in this region. Both new species described herein can be differentiated from these two complexes, and each other, by several morphological characteristics. Cambarus lapidosus and C. burchfielae are differentiated from C. species C by the absence of cervical spines and the presence of 1-2 subpalmar tubercles on the chelae in most specimens; both species are less-punctate across the areola than C. aff. robustus. Cambarus burchfielae is further differentiated from C. lapidosus, C. species C, and C. aff. robustus by the presence of a narrower and sparsely punctate areola, a single weak row of tubercles on the mesial margin of the palm, and the absence of tubercles on the dorsal surface of the dactyl. The newly described species are genetically sister taxa and together are most similar by genetic distance to undescribed members of the C. robustus species complex from the nearby (~30 km) Watauga River basin and most phylogenetically similar to C. aff. robustus from the adjacent New River basin; both are interior basin drainages. The newly-described species are endemic to the Blue Ridge Mountains of western North Carolina and have restricted distributions (<100 km2-150 km2) in small (<4th order) tributaries to the Yadkin River. Cambarus lapidosus is known only from the upper Stony Fork watershed and C. burchfielae is known only from the upper reaches of the adjacent Lewis Fork watershed; both species likely qualify for conservation status protections under narrow geographic range criteria.
Topics: Animals; North Carolina; Astacoidea; Rivers; Animal Distribution
PubMed: 37518167
DOI: 10.11646/zootaxa.5270.2.3 -
Journal of Endodontics Oct 2023This study investigated the effects from the carious cavity and access from it on the fracture resistance of endodontically treated maxillary premolars using finite...
INTRODUCTION
This study investigated the effects from the carious cavity and access from it on the fracture resistance of endodontically treated maxillary premolars using finite element analysis (FEA).
METHODS
A maxillary premolar was used to compare 3 types of access cavity related to having a proximal carious defect: caries-driven access (CDA), conservative access that has a mesial component (MCA), as well as traditional access with the same mesial component (MTA). Cyclic loading was simulated on the occlusal surface, and number of cycles until failure (NCF) was compared with the intact tooth model (IT). Mathematical analysis was done to evaluate the stress distribution patterns and calculated maximum von Mises (vM) and maximum principal stresses (MPS), with emphasis on pericervical region as a specific area of interest.
RESULTS
Maximum vM registered on the IT was 6.14 MPa. CDA provided the highest NCF with 92.28% of the IT, followed by MCA (84.90%) and MTA (83.79%). The vM and MPS analysis showed that the stress values and patterns are affected more by the proximity of the occlusal load to the tooth/restoration interface. Concerning the pericervical region, maximum vM was registered for IT (4.11 MPa), followed by CDA (4.85 MPa) and then MCA (8.13 MPa) and MTA (8.61 MPa), whereas the MPS analysis revealed that CDA showed the highest magnitude of tensile stresses.
CONCLUSIONS
A proximal CDA benefits the mechanical properties of maxillary premolars; however, its impact on the biological aspect should be assessed to provide a ruling for/against it.
Topics: Humans; Bicuspid; Dental Caries Susceptibility; Dental Caries; Models, Dental; Finite Element Analysis; Dental Stress Analysis; Stress, Mechanical; Tooth, Nonvital
PubMed: 37517584
DOI: 10.1016/j.joen.2023.07.022 -
Journal of Endodontics Oct 2023This laboratory study aimed to evaluate the accumulated hard tissue debris (AHTD) and shaping performance following root canal instrumentation with a novel stainless...
INTRODUCTION
This laboratory study aimed to evaluate the accumulated hard tissue debris (AHTD) and shaping performance following root canal instrumentation with a novel stainless steel rotary system (Gentlefile; MedicNRG, Kibbutz Afikim, Israel) compared with two single-file nickel-titanium instruments of different kinematics through micro-computed tomography (micro-CT) analysis.
METHODS
Thirty isthmus-containing mesial roots of human mandibular molars with a curvature of 15°-35° were scanned with micro-CT at an isotropic resolution of 12 μm and randomly assigned to three groups (n = 10) according to the instruments used for canal preparation: Gentlefile (GF; #23/.04), One Curve (OC; #25/.06; Micro-Mega, Besancon, France), and Reciproc Blue R25 (RB; #25/.08; VDW, Munich, Germany). The AHTD, unprepared canal surface area, volume changes, surface area changes, and transportation were evaluated by comparing preoperative and postoperative micro-CT images. In addition, the time required for canal preparation was recorded. Data were statistically analyzed using the one-way analysis of variance (ANOVA) test or the Kruskal-Wallis test at a significance level of 5%.
RESULTS
No significant differences were observed in the percentage of AHTD or in the unprepared canal surface area between the three groups (P > .05). The RB group demonstrated a significantly greater percentage increase in volume and surface area than the GF group (P < .05). The GF and OC groups showed significantly less transportation at 3 mm from the apex than the RB group (P < .001). The OC group required significantly less time for instrumentation than the RB and GF groups (P < .05).
CONCLUSIONS
Instrumentation with GF (#23/.04), OC, and RB yielded similar levels of AHTD and unprepared surface area in isthmus-containing curved canals. GF achieved this with less dentin removal and apical transportation, at the expense of a longer preparation time.
Topics: Humans; Dental Pulp Cavity; X-Ray Microtomography; Root Canal Preparation; Tooth Root; Molar; Equipment Design
PubMed: 37516238
DOI: 10.1016/j.joen.2023.07.019