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BMC Oral Health Sep 2023This study aimed to assess the root canal morphology of primary molars using cone-beam computed tomography (CBCT).
BACKGROUND
This study aimed to assess the root canal morphology of primary molars using cone-beam computed tomography (CBCT).
METHODS
This cross-sectional study evaluated 60 maxillary and mandibular primary first and second molars on CBCT scans of patients retrieved from the archives of Hamadan School of Dentistry between 2018-2020. The teeth were evaluated regarding the number of roots and canals, canal type according to the Vertucci's classification, and root surface concavities. Data were analyzed descriptively and by independent t-test.
RESULTS
The most frequent number of canals and roots in the maxillary right and left first molars was 3 canals (60%) and 3 roots (80%). These values were 4 canals (80%) and 5 canals (50%) with 3 roots in the maxillary right and left second molars, respectively, 4 canals (100%) and 2 roots (50%), and 3 canals (60%) and 2 roots (50%) in mandibular right and left first molars, respectively, and 4 canals (92.3%) and 3 roots (61.5%) in mandibular right and left second molars. Vertucci's type IV was the most common canal type in mesial and distal canals, type I was the most common in mesiobuccal, mesiolingual, distobuccal, and distolingual, and types I and II were the most common in the palatal canal. The maximum and minimum concavities were noted in the buccal (26.7%) and mesial (8.3%) surfaces, respectively.
CONCLUSIONS
A wide variation exists in the number of roots and canals of maxillary and mandibular primary molars, which calls for further attention in treatment of such teeth.
Topics: Humans; Dental Pulp Cavity; Cross-Sectional Studies; Root Canal Therapy; Molar; Cone-Beam Computed Tomography
PubMed: 37749546
DOI: 10.1186/s12903-023-03414-z -
BMC Oral Health Jun 2023This 18-month randomized clinical trial aimed to compare the effectiveness of two topical fluoride applications versus placebo control on preventing development of... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
This 18-month randomized clinical trial aimed to compare the effectiveness of two topical fluoride applications versus placebo control on preventing development of approximal caries in primary teeth.
METHODS
Preschool children were recruited if they had at least one initial approximal carious lesion at the distal surface of the canines, both approximal surfaces of the first molars, or the mesial surface of the second molars assessed from bitewing radiographs. The participants were randomly allocated into 3 intervention groups: Group 1 (placebo control), Group 2 (5% sodium fluoride [NaF] varnish), and Group 3 (38% silver diamine fluoride [SDF]). All agents were applied semiannually. Two calibrated examiners evaluated the caries development from bitewing radiographs. Caries development was recorded when the baseline sound surface or initial approximal carious lesion surface developed dentin caries (beyond the outer one-third of dentine) at the follow-up examination. The intention-to-treat approach was adopted. The Chi-square test was used to analyze the effectiveness of topical fluoride agents in preventing approximal caries development and the effect of other variables. The multi-level logistic regression analysis was performed to assess the relative effectiveness of topical fluoride agents in preventing approximal caries development at the 18-month follow-up.
RESULTS
At baseline, 190 participants with 2,685 sound or initial carries at the approximal surfaces were recruited. No differences in participant demographic backgrounds, oral health related habits, or caries experience were observed among the 3 groups (P > 0.05). After 18 months, 155 (82%) participants remained in the study. The rates of developing approximal caries in Groups 1, 2, and 3 were 24.1%, 17.1%, and 27.2%, respectively (P < 0.001, χ test). After adjusting for confounding factors and clustering effect, the multilevel logistic regression analysis showed no differences in caries development rates between the 3 groups (P > 0.05). Tooth type and the extent of a carious lesion at baseline were the significant factors for caries development.
CONCLUSION
At 18-month follow-up, after adjusting for confounding factors and clustering effect, there were no statistically significant differences in preventing of approximal caries development between the semiannual application of 5%NaF, 38%SDF, or placebo.
TRIAL REGISTRATION
The study was registered in the Thai Clinical Trials Registry under the number TCTR20190315003 on 15/03/2019.
Topics: Humans; Fluorides; Fluorides, Topical; Cariostatic Agents; Dental Caries Susceptibility; Dental Caries; Sodium Fluoride; Tooth, Deciduous
PubMed: 37268914
DOI: 10.1186/s12903-023-03045-4 -
Journal of Microscopy and Ultrastructure 2018Enamel is one of the most important structures of the tooth, both functionally and aesthetically. Because of the highly mineralized nature of enamel, its structure is...
INTRODUCTION
Enamel is one of the most important structures of the tooth, both functionally and aesthetically. Because of the highly mineralized nature of enamel, its structure is difficult to study under routine light microscopy. Since scanning electron microscopy (SEM) offers the possibility of studying structures under very high magnification without altering the gross specimen, it is one of the best methods to study the enamel surface.
AIMS AND OBJECTIVES
To study and compare the surface morphology and morphometry of enamel on various surfaces of permanent dentition.
MATERIALS AND METHODS
A total of 20 permanent teeth were analyzed under the SEM. In both anterior and posterior teeth, four surfaces - mesial, distal, labial, and lingual - in three thirds - cervical, middle, and incisal - were studied. In addition, the occlusal surface was also studied for the posterior teeth. The different prism morphology and prism dimensions were recorded.
RESULTS
Based on our observations, we could definitely identify striae of retzius, debris, and cracks under ×50 magnification. Three morphological patterns of prism arrangement were identified: Type 1 - shallow prisms, Type 2 - well-defined prisms, Type 3 - microporosities, on analyzing the mesial, distal, labial, lingual, and occlusal surfaces of the permanent teeth, at ×3000 magnification. The prisms were measured under ×6000 magnification and the results showed larger prisms in posterior than in anterior teeth.
CONCLUSION
The study aided us in categorizing the enamel prism structure based on morphology and morphometry in anterior and posterior teeth of the permanent dentition.
PubMed: 30221142
DOI: 10.4103/JMAU.JMAU_27_18 -
PloS One 2020To assess and compare the enamel surface quality after interproximal enamel reduction (IPR) was performed with different systems and to study the relation between acid... (Comparative Study)
Comparative Study
OBJECTIVES
To assess and compare the enamel surface quality after interproximal enamel reduction (IPR) was performed with different systems and to study the relation between acid penetration depth and enamel surface quality as well as the importance of remineralization.
METHODS
Sixty-five extracted teeth were randomly allocated to five experimental groups: untreated control, manual with New Metal Strips, mechanical with oscillating segment (OS) discs, Safe-Tipped Bur Kit, and the Ortho-Strip, followed by 30 s of polishing with the Softflex system and the Compo-system after treating the tooth with OS discs. Mesial surfaces were demineralized for 24 h and distal surfaces were subjected to interchanging demineralization and remineralization cycles of 24 h each for 18 days. The analysis was carried out by profilometry, scanning electron microscopy, and polarization microscopy.
RESULTS
After IPR and polishing, enamel roughness was reduced for all systems tested except for the Essix Safe-Tipped Bur Kit. Subsequent demineralization increased enamel roughness in all groups except controls beyond the original level prior to IPR except for IPR with New Metal Strips or Ortho-Strips and subsequent polishing. Cyclic demineralization and remineralization for 18 days yielded a reduction in acid penetration depth and an increase in surface smoothness, which correlated with each other only for controls and treatment with New Metal Strips or Ortho-Strips.
CONCLUSIONS
Manual IPR, using New Metal Strips and, even more, the oscillating IPR system Ortho-Strips, yielded smoother interproximal enamel surfaces and less acid penetration depth than the IPR systems with OS discs and the Safe-Tipped Bur Kit after polishing and 18 days of cyclic demineralization and remineralization. Irrespective of the IPR procedure, proper remineralization of IPR-treated surfaces is advisable to reduce caries susceptibility.
Topics: Dental Enamel; Dental Etching; Humans; Microscopy, Electron, Scanning; Microscopy, Polarization; Surface Properties; Tooth
PubMed: 32119700
DOI: 10.1371/journal.pone.0229595 -
International Journal of Dentistry 2022The use of technology in bulk-fill composites (BCs) has reduced the stresses caused by polymerization shrinkage, debonding, microleakage, or posttreatment sensitivity in...
INTRODUCTION
The use of technology in bulk-fill composites (BCs) has reduced the stresses caused by polymerization shrinkage, debonding, microleakage, or posttreatment sensitivity in them. This study was conducted to determine whether bleaching affects the microleakage of class II restoration with bulk-fill material.
MATERIALS AND METHODS
This laboratory study was performed on 40 normal human premolars in 4 groups ( = 20). Class II cavities were prepared in mesial and distal surfaces of the teeth with dimensions of 2 × 2 × 4 mm. Then, based on the bleaching process by 20% carbamide peroxide gel and using two types of composites, the restored cavities were randomly divided into 4 groups: (1) CC without bleaching (CC group), (2) BC without bleaching (BC group), (3) CC with bleaching (CCB group), and (4) BC with bleaching (BCB group). Then, the samples were thermocycled for 1000 cycles at a temperature range of 5-55°C, and they were immersed in 0.6% alkaline fuchsine in order to penetrate into the pigment for 24 h. After cutting, the samples were placed under a stereomicroscope (40%) to determine microleakage. The data were analyzed using one-way analysis of variance (ANOVA), and a value <0.05 was considered as statistically significant.
RESULTS
Microleakage was determined in the CC group (0.97 ± 0.42), BC group (1.08 ± 0.54), CCB group (1.19 ± 0.37), and BCB group (0.30 ± 0.47). There were also no significant differences in the mean microleakage between the groups. No cases with zero microleakage (no microleakage) and grade 3 of microleakage (pigment penetration into the axial wall) were observed in the samples. Also, a two-by-two comparison of significant differences between CC and BC groups (=0.89), CC and CCB groups (=0.45), CC and BCB groups (=0.11), BC and CCB groups (=0.87), BC and BCB groups (=0.41), and CCB and BCB groups (=0.86) showed that the difference was not statistically significant.
CONCLUSION
Results showed no difference between microleakage of BC and CC with and without bleaching, and bleaching had the same effect on microleakage of these two types of composites.
PubMed: 35035487
DOI: 10.1155/2022/9924553 -
The Angle Orthodontist May 2016To develop a method to quickly estimate the location of center of resistance (CR) in mesial-distal (MD) and buccal-lingual (BL) directions from the tooth's image.
OBJECTIVE
To develop a method to quickly estimate the location of center of resistance (CR) in mesial-distal (MD) and buccal-lingual (BL) directions from the tooth's image.
MATERIALS AND METHODS
The maxillary cone-beam computed tomography (CBCT) scans of 18 patients were used. Finite element (FE) models of the canines and their surrounding tissues were built based on their CBCT scans to calculate the locations of CR. Root length, centroid of the contact surface (CCS), and centroid of projection of the contact surface (CPCS) were also obtained from the images. The CCS and CPCS locations were projected on the tooth's long axis, which were represented as percentages of the root length measured from the root's apex.
RESULTS
Using the FE results as the standards, the errors of using CCS or CPCS to estimate CR were calculated. The average location of CR calculated using the FE method was 60.2% measured from the root's apex in the MD direction and 58.4% in the BL direction. The location of the CCS was 60.9%. The difference in CR was 0.7% in the MD direction and 2.5% in the BL direction. The location of CPCS was 60.2% in the MD direction and 59.1% in the BL direction, which resulted in a 0.1% and 0.8% difference with the reference CR, respectively. The average difference of CR in the MD and BL directions was small but statistically significant (P < .05).
CONCLUSION
The locations of the CR of a human canine in the MD and BL directions can be estimated by finding the CPCSs in those directions.
Topics: Cone-Beam Computed Tomography; Cuspid; Humans; Incisor; Tooth Root; Tooth, Impacted
PubMed: 26401827
DOI: 10.2319/051215-322.1 -
Quantitative Imaging in Medicine and... Apr 2015Currently, a relevant proportion of all histopathologically proven focal cortical dysplasia (FCD) escape visual detection; this shows the need for additional... (Review)
Review
Currently, a relevant proportion of all histopathologically proven focal cortical dysplasia (FCD) escape visual detection; this shows the need for additional improvements in analyzing MRI data. A positive MRI is still the strongest prognostic factor for postoperative freedom of seizures. Among several post-processing methods voxel-based morphometry (VBM) of T1- and T2-weighted sequences and T2 relaxometry are routinely applied in pre-surgical diagnostics of cryptogenic epilepsy in epilepsy centers. VBM is superior to conventional visual analysis with 9-15% more identified epileptogenic foci, while T2 relaxometry has its main application in (mesial) temporal lobe epilepsy. Further methods such as surface-based morphometry (SBM) or diffusion tensor imaging are promising but there is a lack of current studies comparing their individual diagnostic value. Post-processing methods represent an important addition to conventional visual analysis but need to be interpreted with expertise and experience so that they should be apprehended as a complementary tool within the context of the multi-modal evaluation of epilepsy patients. This review will give an overview of existing post-processing methods of structural MRI and outline their clinical relevance in detection of epileptogenic structural changes.
PubMed: 25853079
DOI: 10.3978/j.issn.2223-4292.2015.01.10 -
Clinical Oral Investigations Apr 2022To evaluate re-osseointegration after electrolytic cleaning and regenerative therapy of dental implants with peri-implantitis in humans.
OBJECTIVE
To evaluate re-osseointegration after electrolytic cleaning and regenerative therapy of dental implants with peri-implantitis in humans.
MATERIAL AND METHODS
Four dental implants that developed peri-implantitis underwent electrolytic cleaning followed by regenerative therapy with guided bone regeneration. All four implants developed recurrent peri-implantitis and were therefore explanted 6 to 13 months later. Radiographic bone level, probing depth, and bleeding on probing were determined at the time of surgery, 6 months later, and before implant retrieval. The peri-implant tissues were histologically and histomorphometrically analyzed.
RESULTS
All four implants demonstrated radiographic and histological bone gain, reduced probing depth, and bleeding on probing. Radiographic bone gain was 5.8 mm mesially and 4.8 mm distally for implant #1, 3.3 mm and 2.3 mm for implant #2, 3.1 mm and 0.5 mm for implant #3, and 3.5 mm and 2.8 mm for implant #4. The histometric mean and maximum vertical bone gain for implant #1 to #4 was 1.65 mm and 2.54 mm, 3.04 mm and 3.47 mm, 0.43 mm and 1.27 mm, and 4.16 mm and 5.22 mm, respectively. The percentage of re-osseointegration for implant #1 to #4 was 21.0%, 36.9%, 5.7%, and 39.0%, respectively. In one implant, the newly formed bone was deposited directly onto calculus on the implant surface.
CONCLUSIONS
We found that (1) re-osseointegration is possible on a formerly contaminated implant surface and (2) the electrolytic cleaning process seems to be effective enough at sites with calculus residues.
CLINICAL RELEVANCE
Since re-osseointegration can be achieved by electrolytic cleaning, this decontamination technique may be considered as a future treatment concept.
Topics: Bone Regeneration; Dental Implants; Humans; Osseointegration; Peri-Implantitis
PubMed: 35244779
DOI: 10.1007/s00784-021-04345-1 -
Journal of Fish Biology Oct 2022Teeth are an integral component of feeding ecology, with a clear link between tooth morphology and diet, as without suitable dentition prey cannot be captured nor broken...
Teeth are an integral component of feeding ecology, with a clear link between tooth morphology and diet, as without suitable dentition prey cannot be captured nor broken down for consumption. Bull sharks, Carcharhinus leucas, undergo an ontogenetic niche shift from freshwater to marine habitats, which raises the question: does tooth morphology change with ontogeny? Tooth shape, surface area and thickness were measured using both morphometrics and elliptic Fourier analysis to determine if morphology varied with position in the jaw and if there was an ontogenetic change concordant with this niche shift. Significant ontogenetic differences in tooth morphology as a function of position in the jaw and shark total length were found, with upper and lower jaws of bull sharks presenting two different tooth morphologies. Tooth shape and thickness fell into two groupings, anterior and posterior, in both the upper and lower jaws. Tooth surface area, however, indicated three groupings, mesial, intermediate and distal, in both the upper and lower jaws. While tooth morphology changed significantly with size, showing an inflection at sharks of 135 cm total length, each morphological aspect retained the same tooth groupings throughout. These ontogenetic differences in tooth morphologies reflect tooth strength, prey handling and heterodonty.
Topics: Animals; Ecosystem; Jaw; Sharks; Tooth; Diet
PubMed: 35848707
DOI: 10.1111/jfb.15170 -
Molecules (Basel, Switzerland) Sep 2021Recently, translucent zirconia has become the most prevalent material used as a restorative material. This study aimed to compare the crown fracture load of the four... (Comparative Study)
Comparative Study
Recently, translucent zirconia has become the most prevalent material used as a restorative material. This study aimed to compare the crown fracture load of the four most common different translucent zirconia brands available in the market at 1.5 mm thickness. Standardized tooth preparations for a full ceramic crown were designed digitally with software (AutoCAD) by placing a 1.0 mm chamfer margin and 1.5 mm occluso-cervical curvature for the crown sample manufacturing. Stylized crowns were chosen to control the thickness of the crown. The axial and occlusal thickness were standardized to 1.5 mm thickness except at the central pit, which was 1.3 mm thick. The STL file for the tooth dies was prepared using software (3Shape TRIOS Patient Monitoring, Copenhagen, Denmark). The tooth dies were printed with a resin material (NextDent Model 2.0, Vertex-Dental B.V., Soesterberg, The Netherlands) using a 3D printing software (3D Sprint Client Version 3.0.0.2494) from a 3D printer (NextDent™ 5100, Vertex-Dental B.V., Soesterberg, The Netherlands). The printing layer thickness was 50 µm. Then, a total of twenty-eight ( = 28) stylized crowns were milled out of AmannGirrbach (Amann Girrbach GmbH, Pforzheim, Germany) ( = 7), Cercon HT (Dentsply Sirona, Bensheim, Germany) ( = 7), Cercon XT (Dentsply Sirona, Bensheim, Germany) ( = 7), and Vita YZ XT (Zahnfabrik, Bäd Sackingen, Germany) ( = 7). Following sintering the crowns, sandblasting was performed and they were bonded to the tooth dies with the resin cement (RelyX U-200, 3M ESPE, Seefeld, Germany) and permitted to self-cure under finger pressure for 6 min. The crowns were loaded on the occlusal surface in a universal testing machine (MTS Centurion) with a stainless-steel ball indenter (7 mm radius) with a loading rate of 1 mm/min to contact the stylized crowns on each of the four cusps until failure. A rubber sheet (1.5 mm thickness) was positioned between the crown and indenter, which helped with the load distribution. Statistical analysis was done using SPSS version 20 (IBM Company, Chicago, USA). The fracture loads were analyzed using Dunnett's T3 test, and the number of cracks was analyzed using the Mann-Whitney U test among the groups. The significant level was set at value = 0.05. The mean fracture loads were 3086.54 ± 441.74 N, 4804.94 ± 70.12 N, 3317.76 ± 199.80 N, and 2921.87 ± 349.67 N for AmannGirrbac, Cercon HT, Cercon XT, and Vita YZ XT, respectively. The mean fracture loads for the surfaces with the greatest number of cracks (excluding the occlusal surfaces) were on the lingual surface for AmannGirrbach and Cercon HT, on the distal and mesial for Cercon XT, and on the buccal for Vita YZ XT. We found that the AmannGirrbach had the most overall cracks. Cercon XT had the greatest number of occlusal cracks and appeared to be the most shattered. Cercon HT had the least number of cracks. In conclusion, Cercon HT presented the best strength properties, the highest fracture load, and no visible cracks. AmannGirrbach presented the lowest strength properties.
Topics: Particle Size; Zirconium
PubMed: 34500741
DOI: 10.3390/molecules26175308