Minerva dental and oral science最新文献

Background: Yogurt, due to its rich casein phosphopeptide (CPP) content could promote remineralization of enamel. Contrary to the age-old usage of animal milk based yogurt, vegan dairy products are gaining momentum due to multiple reasons. Considering this change, the aim of the present study was to assess the in vitro effect of animal and plant-based yogurt extracts on demineralization of enamel.

Methods: Enamel windows were prepared on the crowns of sixty premolar teeth using nail paint. Teeth were divided into four groups of fifteen each and were treated with distilled water, demineralizing agent, solution with a mixture of demineralizing agent and yogurt supernatants, respectively for 96 hrs. Quantitative analysis was done using EDXRF (baseline and postexperimental calcium and phosphorus content). Additionally, confocal microscopic analysis was performed to assess the extent of demineralization.

Results: The animal-based yogurt (Group III) had the highest post experimental calcium value (mean±SD=81.15±5.02) and positive percentage of change in calcium level (15%; P=0.007) among the groups. This was followed by plant-based yogurt (Group IV) (mean calcium= 76.18±5.12; positive percentage change =8.11%; P=0.003).

Conclusions: Animal based yogurt could provide higher protection against enamel demineralization when compared to plant-based yogurt.

Background: Primary stability of dental implant is an important prerequisite for achieving osseointegration. This study was conducted to evaluate the effects of photobiomodulation therapy on bone formation-around implants by measuring the implant removal torque and implant stability quotient.

Methods: This study was conducted in six adult male sheep. Four implants were placed on each side of the lower border of the mandible. The implant beds were prepared to a size of 10 mm in length and 4.8 mm in width, to receive an implant of 8 mm in length and 4 mm in width. Laser application to the socket was performed just before implant placement, and was immediately administered to the surface of the implant and the peri-implant bone before suturing of the wound. The therapy was continued twice daily for the next seven consecutive days. The animals were sacrificed at 4, 8, and 12 weeks, with two animals per time point. The implant-removal torque was determined with an electronic wrench, and the implant stability quotient (ISQ) was assessed with an Ostell device.

Results: The laser treated sides showed significantly higher removal torque and ISQ, at the three-time points (P<0.05). At 4 weeks, the ISQ was 61.44 (±10.4) in the laser group and 48.2 (±16.7) in the control group. At 8 weeks, the ISQ increased to 62.2 (±5.5) in the laser group and 56.1 (±4.3) in the control group. At 12 weeks, the ISQ was 67 (±4.5) in the laser group and 61.875 (±6.3) in the control group. The removal torque at 4 weeks was 218.6 (±62.6) in the laser group and 147.6 (±40.9) in the control group. At 8 weeks, the removal torque increased to 370.5 (±33.3) in the laser group and 250.2 (±25.0) in the control group. At 12 weeks, the removal torque increased to 912.6 (±177.2) in the laser group and 512.1 (±122.6) in the control group.

Conclusions: Photobiomodulation enhances bone formation and improves implant stability in implants with overzealously prepared oversized implant beds.

Background: During the debonding phase every clinician has to take care of preserving the enamel structure and tooth temperature. The objective of this study was to analyze in vitro the increase of the pulp chamber temperature and the wearing of enamel surface, during adhesive removal after debonding.

Methods: Sixty extracted human teeth were selected. An orthodontic bracket was bonded on each tooth and after bracket removal, intraoral scanner pictures were used to evaluate ARI for each tooth. Three different burs were tested: tungsten-carbide multiple blades, arkansas stone and ceramic bur. A mechanical arm controlled by a dedicated software was used to reproduce a repeatable act of composite removal. To analyze in vitro the pulp chamber temperature during the composite removal procedure, teeth were treated endodontically placing a thermocouple through the root canal from the apex. A software registered temperature changes in a continuous manner. The enamel surface of every tooth was tested after the removal of composite with an optical stereoscopic microscope.

Results: An association existed between maximum internal pulp chamber temperature variation and irrigation (P<0.0001) and between maximum internal pulp chamber temperature variation and bur type (P=0.0133), with a significantly lower temperature increase produced by the arkansas bur. A significant difference among groups was detected for ESI and EDI assessment (P=0.002, P=0.010).

Conclusions: Considering the initial setup, temperature variation analysis showed more conservative results using the arkansas burs with irrigation. ESI and EDI indexes showed significant enamel surface damage using tungsten-carbide burs.

Background: The aim of the current study was to propose a classification of impacted cuspids, and bicuspids based on their spatial position in the maxillary and mandibular arches and their radiological appearance.

Methods: This prospective study was conducted including all the patients who reported to our center for extractions, orthodontic treatment, missing permanent cuspids/bicuspids, removal of third molar teeth. All patients who reported within a time frame of 6 months were enrolled in the study. Orthopantomogram was advised for all the patients as a part of diagnostic work up. The panoramic radiographs and clinical data were reviewed and patients with evidence of impacted bicuspids and cuspids were included in the study and were advised to undergo a cone beam computed tomography to evaluate the 3-dimensional position of the impacted teeth. Treatment plan was decided based on the position of the impacted teeth and feasibility for orthodontic movement. Standard surgical protocol was followed for all the patients. The duration of the procedure from the time of incision till the suturing were tabulated and the difficulty of extraction was correlated with the current Difficulty Index to validate the same.

Results: A total number of 4165 patients were enrolled in the study and based on the inclusion and exclusion criteria, 3680 patients were excluded and 487 patients with impacted cuspids/bicuspids were included in the study. A total number of 231 patients had impacted maxillary cuspids and bicuspids and 256 cases had impacted mandibular cuspids/bicuspids. Amongst the 256 mandibular cuspid and bicuspid that were impacted, 62% were in position C while the rest of 38% were in position B. More than ⅓ of the teeth which were in position C had transmigrated (35%). Seventy-three percent of the maxillary teeth were in position C and 69% of these teeth were either transmigrated (29%), or were horizontally (38%) placed in the alveolus or inverted (2%). The rest of the 31% were found to be either mesially inclined or vertical. The average Difficulty Index for maxillary teeth was 8 and mandibular teeth was 9. Mandibular cuspids and bicuspids in position B and C took longer time for surgical removal compared to the maxillary teeth and this was statistically significant.

Conclusions: The proposed clinical classification on impacted mandibular cuspids and bicuspids provides a structured approach to plan the treatment based on the 3-dimensional position of the teeth in the arch.

Introduction: Ossification disorders can affect the stylohyoid ligament as well the stylomandibular ligament. The symptomathology between those syndromes and other pathologies it has been a problem because there is not a guideline.

Evidence acquisition: With the aim to establish prevalence, diagnosis and etiopathogenesis of Eagle and Ernest syndromes, a scoping review was performed base on PRISMA criteria.

Evidence synthesis: To review stylohyoid ligament and Eagle Syndrome 93 articles were selected. Three articles regarding the stylomandibular ligament and Ernest Syndrome were founded and selected.

Conclusions: Both syndromes should be clinically diagnosed and corroborate with imaging (2D or 3D), although imaging in Ernest Syndrome is not clear as well in Eagle Syndrome. A decisional algorithm for diagnosis of Eagle Syndrome and Ernest Syndrome is presented.

Background: Mandibular fractures are universal in distribution, but its etiologies and presentation patterns differ from one country to another because of varying socioeconomic, cultural and geographical factors. We analyzed the etiological factors and presentation patterns of mandibular fractures in a tertiary hospital at Nigeria's second largest city.

Methods: Patients with isolated mandibular fractures at Aminu Kano Teaching Hospital, Kano were prospectively reviewed over a 12-months period. Patients' demographic information and fracture characteristics (etiology, site, pattern and number of fracture) were recorded and analyzed.

Results: One hundred and forty-eight patients presented with 180 mandibular fractures. There were eight-fold higher men with mandibular fractures than women (M: F =8.3:1) with highest incidence in third decade of life. Road traffic accidents (84.46%) was the major etiology while iatrogenic fracture (0.68%) was found in one patient. Mandibular body was the most fractured site (41.11%) with parasymphyseal and angle regions accounting for 27.78% and 23.89% of total recorded fractures respectively.

Conclusions: Mandibular fractures in Kano, Northwest Nigeria occurred predominantly in men in the third decade and are mostly caused by road traffic accidents. The majority of these fractures involved the mandibular body.

Background: The purpose of this study was to compare the color stability and marginal adaption of lithium disilicate veneers before and after thermocycling using various resin composite materials employed as cement.

Methods: Laminate veneer preparation was done on an acrylic tooth according to standardized procedures. The veneer preparations were duplicated into twenty-one dies. The veneers were fabricated from lithium disilicate using the CEREC in Lab system. According to the cement type, the twenty-one die specimens were randomly divided into three equal groups: group I, with light cured adhesive resin cement (N.=7), group II, with flowable light cured composite, and group III, with preheated nano filled composite. The cemented specimens underwent 5000 thermocycling cycles. Color was assessed using a reflective spectrophotometer. The vertical marginal gap, following cementation and thermocycling, was measured using a digital microscope. One-way ANOVA followed by Tukey's post-hoc test was used to statistically assess the data.

Results: After thermocycling, there was no statistically significant difference in ΔE among cement type groups for color stability (P=0.369). However, the preheated composite showed the lowest ΔE mean values. Within adhesive resin cement and flowable composite groups, marginal gap means values recorded after thermocycling were significantly higher than those after cementation (P=0.013 and P<0.001, respectively).

Conclusions: Although preheated composite cement showed the highest marginal discrepancy, it would be the best choice regarding color stability.

Background: The treatments with clear aligners (CA) showed an exponential higher percentage in the last years being almost invisible with major patient acceptability and a resulting improvement in quality of life. CA are composed of thermoplastic polyurethane not inert but subjected to changes due to heating and humidity, chewing forces, and prolonged exposure to enzymes in saliva in the oral cavity and external factors. Cigarette smoke (CS) and the aerosol produced by tobacco products with reduced health risks may be considered among the external factors affecting CA. The purpose of this study was the assessment of optical properties (absorbance and transmittance) and roughness of CA after in vitro aging due to exposition to CS and THS2.2, compared to controls. The secondary objective will be the investigation of CS and THS2.2 effects on resin composite inside aligners used for attachments during treatment with CA.

Methods: A total number of 60 CA units will be used and equally divided in three different groups (20 in each): CS group exposed to reference cigarettes smoking, THS2.2 group exposed to aerosol from 20 heat-not-burn sticks, and control group, CG to pure air only. The aligners will present ten introflection for the attachments on the anterior part. In accordance with ISO standard 3402, 3R4F cigarettes and THS2.2 tobacco sticks must undergo conditioning for a minimum of 48 hours and a maximum of 21 days at a temperature of 22±1 °C and a relative humidity of 60±3%.

Results: Using spectrophotometry, the optical characteristics (absorbance and transmittance) of each aligner will be evaluated after aging (Jasco UV-vis V630PC, Tokyo, Japan). Each aligner will be cut with a rotating saw from canine to canine prior to the measurements in order to lop off the lingual region and displaying the labial barrier. The absorbance and transmittance measurements will be collected and statistically analyzed with a significance of P<0.05.

Conclusions: Surface roughness of the aligners and attachments inside them will be assessed by 3D scanning microscopy (Infinite Focus G4h). Color of resin composite will be assessed using the (CIE Lab) Commission Internationale de l'Eclairage L*a*b* color space by means of Olympus CrystalEyef dental spectrophotometer. Clinicians should advise patients to refrain from smoking and drinking coffee or tea while wearing aligners for two reasons: first, the color change is unacceptably noticeable when wearing aligners, and second, the material's chemical composition may be slightly altered, which could affect the intended dental movements.

Background: The purpose of the current study was to evaluate the effect of Diode LLLT 650 nm, TEMPO oxidized Nano-fibrillated cellulose mixed with Nano-Amorphous calcium phosphate, and their combination on bone healing in rabbit tibia using H&E staining and computed tomography.

Methods: Eighteen adult male New Zealand rabbits were selected, two circular bone defects were created in each tibia, resulting in four bony defects in each rabbit, representing the four tested groups; group A (negative control), group B (filled with mineralized nano-cellulose), group C (combination), group D (laser). Animals were euthanized after two weeks and one month, defects were assessed by CT for bone density, then histological samples were examined by H&E stain.

Results: In both evaluation periods, group D recorded the greatest mean area percent of new bone formation and bone density, followed by group A, while group C recorded the lowest value. Groups A and D showed full closure of the defects, while groups B and C showed partial defect closure with retained bone graft material. H&E and CT showed that Laser group had the best results of defects healing, bone density and new bone formation, followed by the negative control group.

Conclusions: Diode laser 650nm photobiomodulation significantly improved bone defects healing. Mineralized nano-cellulose experimental bone substitute material showed a delayed effect in bone healing and graft material resorption. The combination of LLLT with the graft material had no positive outcome on bone defect healing.