December 1, 2017
Five new hybrid tooth forms take shape
There is no correlation between the shapes of teeth and sex of patients. The highest percentage of tooth shapes in the studied population was hybrid forms such as triangular oval, square oval with scalloped lateral incisors, and oval rectangular. The findings are from a study published online September 27 in Journal of Esthetic and Restorative Dentistry.
Researchers designed the study to evaluate different tooth shapes and suggest hybrid shapes for clinicians to use to restore function, esthetics, or both for male and female patients.
Researchers randomly chose 460 students (285 female, 175 male) from the University of Los Andes, Chile, for the study. They obtained 920 digital photos (2 from each patient) with a camera positioned perpendicular to the floor at a distance of 40 centimeters from the patients’ noses. Photos were evaluated by 3 calibrated operators.
Tooth shapes were split into 2 groups: pure basic forms and combined hybrid forms. Pure basic forms comprised oval (0), triangular (T), square (S), and rectangular (R). Combined hybrid forms consisted of oval rectangular (OR), triangular rectangular (TR), triangular oval (TO), square oval with flat lateral incisors (SOF), and square oval with scalloped lateral incisors (SOS).
Researchers measured correct sex identification among laypeople, dentists, and dental students. They used the same photos to measure correct responses from 10 dentists, 10 dental students, and 10 laypeople. They used a 1-way analysis of variance to analyze the data.
Researchers found the greatest percentage of tooth shapes observed in the population were hybrid forms. As a result, they proposed 5 new hybrid tooth shapes: TO, SOS, OR, SOF, and TR.
The percentage of tooth shapes in hybrid forms was 20.87% (TO), 20.65%(SOS), 19.57% (OR), 16.96% (SOF), and 30% (TR). Within pure basic forms the percentages were 6.52% (O), 3.48% (S), 3.26% (T), and 2.39% (R). Tooth sex selection among different evaluators was not statistically significant.
Researchers also found that hybrid forms TO, SOS, and OR showed similar percentages among one another and when comparing males and females, while SOF showed a higher percentage for females and TR showed a higher percentage for males.
“These results might also reflect the idea that not only experts believe that there is a specific form for woman and man,” the authors noted, “but the society in general has also the same erroneous perception, which is not observed in reality, as seen in this study.”
Read the original article here.
Consulting Editor: Luiz Meirelles DDS, MS, PhD
Survival rates and patient-reported outcomes of zirconia-based fixed implants
Two-layered fixed dental prostheses (FDPs) made from zirconia/fluorapatite bridges may be highly satisfying to patients, but they also are vulnerable to technical problems like occlusal roughness and chipping. The findings are from a study published online September 21 in Clinical Oral Implants Research.
Researchers designed the study to measure the success rate and patient-reported outcome measures (PROM) of all ceramic FDPs by applying modified criteria from the U.S. Public Health Service and the preparation of Kaplan-Meier plots.
Researchers recruited 13 patients (7 men, 6 women) for bone level measurements. They fabricated a zirconia framework with a minimal thickness of 0.5 millimeters to 0.7 millimeters for 3-unit bridges using computer-aided design and computer-aided manufacturing. Unsupported veneering ceramic did not exceed 2.5 mm. All FDPs were cemented with a dual-curing Lucite composite.
Researchers scheduled all follow-up appointments up to 5 years after implant installation. All appointments included an intraoral visual and tactile control of the restoration’s surface. Researchers measured changes in interproximal bone levels by recording the distance from the abutment shoulder to the first visible bone to implant contact at the mesial and distal aspect of each implant.
Researchers used visual analog scales (VAS) to record patients’ satisfaction before implant installation, after the final restoration and at the 1-, 3-, and 5-year follow-up appointments. VAS data included patients’ perception of function, esthetics, sense, speech, and self-esteem.
Patients’ satisfaction ratings within Alpha and Bravo ranges were considered a success. A Charlie rating absent any Delta rating was considered a nonsuccess but survival. The presence of any Delta rating constituted a failure.
None of the restorations required replacement. Researchers noted 7 FDPs with obvious roughness and 3 others with extended veneer chipping, for a calculated success rate of 38.5%. The occurrence of veneer chipping and occlusal roughness was found to be statistically significant.
The mean (standard deviation [SD] pocket probing death (PPD) was 3.0 (0.7) mm at the time of prosthetic delivery, and 3.5 (0.7) mm at the 5-year follow-up. The modified bleeding index score (SD) increased from 0.5 mm (0.3) mm at the time of prosthetic delivery to 1.1 (0.5) mm at the 5-year follow-up. The modified plaque index score (SD) increased from 0.5 (0.4) mm at the time of prosthetic delivery to 0.7 (0.5) mm at the 5-year follow-up.
With the exception of speech, patients reported much higher VAS scores with respect to function, esthetics, sense, and self-esteem right after the final restoration was cemented. Patients’ VAS scores related to function, esthetics, and self-esteem stayed stable over the course of the 5-year follow-up, while scores related to sense and speech increased.
“From a patient’s point of view, the applied treatment met the expectations even if the dentist’s claims are different,” the researchers noted.
“Prospectively, this may change if the occurrence of chip-off fractures grows in the further observation period, potentially resulting in clinically unacceptable situations that cannot be repaired without replacement.”
Read the original article here.
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Clinical report: direct composite resins to restore large class IV fractures
Using direct composite resins to restore large class IV fractures is a good option that requires detailed treatment planning and artistic skills to achieve optimal results, according to a clinical report published in the October 2017 issue of The Journal of Prosthetic Dentistry.
The report details a step-by-step process for using a layered, multichromatic composite resin restoration to restore a fractured maxillary lateral incisor in a 38-year-old male patient. The man’s history revealed trauma to his maxillary left lateral incisor 6 to 8 months before his dental appointment and mild tooth sensitivity on stimuli.
The authors evaluated existing tooth integrity by noting that the maxillary left central incisor and canine responded within normal limits to cold pulp testing and that the maxillary left lateral incisor responded with nonlingering tooth hypersensitivity. They further observed that a full 360 degrees of enamel favored a direct restorative procedure.
Esthetically, the authors observed a combination of white hypocalcified and brown stains with stained craze lines on the maxillary right lateral incisor and both central incisors. They also noted the presence of scalloped gingival architecture with short and thick papillae with symmetrical axial inclination.
The authors began treatment with at-home bleaching using a 10% carbamide peroxide gel combined with a nonreservoir, nonscalloped, nightguard bleaching tray for 4 weeks. They recorded the final shade as C1, based on the Vita classical shade guide.
Authors made a definitive cast and diagnostic waxing, then fabricated a polyvinyl siloxane lingual matrix before the restoration. They prepared a 1.5-millimeter, 75-degree functional esthetic enamel bevel with a fine flame diamond rotary instrument on the facial surface, then placed a 45-degree lingual functional bevel. A coarse disk was then used to extend the bevels interproximally and the facial bevel apically. They also placed polytetrafluoroethylene tape on the maxillary left central incisor and canine to prevent bonding to adjacent teeth.
Next, authors placed a layer of C2 body shade microhybrid composite resin in the matrix and seated it. The composite resin was then sculpted against the lingual bevel and polymerized for 20 seconds. Then they placed a thin layer of opaque white composite resin and ensured it stayed 1 mm short of the incisal edge. They shaped the C2 body shade composite resin to replace the dentin layer, and reproduced the hypocalcified white spots with a flowable opaque white composite resin.
The authors extended the increment over the beveled facial surface, then placed a final increment of enamel white composite resin on the facial surface that extended from the beveled area toward the incisal edge. They lubricated the composite resin placement instrument with wetting resin to ease the handling of the composite resin.
For the finishing process, the authors used coarse and medium-coarse disks to reproduce the contours of the contralateral tooth, followed by a fine flame and an extra-fine needle diamond rotary instrument for texture and microanatomy. They used finishing strips interproximally to eliminate flash and aluminum oxide polishing points on the lingual surface after functional occlusal adjustment. They conducted a final evaluation of shade and texture 7 days postoperatively. Functional evaluation was completed at 6, 12, and 24 months postoperatively.
Despite the need for extensive treatment planning and technical skill, the authors noted that the procedure in this clinical report was executed by a junior dental student under faculty supervision and guidance.
“Teaching the fundamentals of direct highly esthetic restorative procedures at the pre-doctoral level in combination with complex preclinical simulation laboratory exercises,” they concluded, “will help in the early development of the skills needed to achieve good results.”
Read the original article here.
Implants with guided bone regeneration stand the test of time
The early placement of implants with contour augmentation through guided bone regeneration produced effective long-term results, according to a study published online October 26 in Journal of Dental Research.
Researchers designed the study with a 2-fold purpose: to judge the long-term integrity of early implant placement with simultaneous contour augmentation through guided bone regeneration (GBR) after 10 years and to identify factors that affected the regenerative outcomes of facial bone dimensions after 10 years.
Researchers recruited 20 patients (5 men and 15 women) for the study. Thirteen patients were healthy, and 7 had preexisting conditions such as cardiovascular disease, osteoporosis, diabetes, and brain tumor. Treatment sites included 14 central incisors, 3 lateral incisors, 1 canine, and 2 first premolars.
Researchers began by performing a flapless tooth extraction without ridge preservation. After an 8-week healing period, researchers placed a bone-level implant and performed a simultaneous contour augmentation with GBR using a 2-layer composite graft. The graft was composed of locally harvested autogenous bone chips combined with a thin layer of deproteinized bovine mineral and covered with a collagen membrane.
The cast analysis monitored peri-implant mucosa levels over time. Researchers based the pink esthetic score on the respective casts and intraoral pictures. They used cone-beam computed tomography (CBCT) to conduct a 3-dimensional radiographic analysis of the surgical site and 2 follow-up examinations at 6 and 10 years. Preoperative analysis included facial soft-tissue and socket wall thickness, facial wall height, and crest width proximal to the extraction site. Researchers defined the peak of facial bone wall height as the distance from the facial bone crest to the implant shoulder.
Researchers focused on 5 parameters for their analysis: peri-implant suppuration, modified plaque index (mPLI), modified sulcus bleeding index (mBLI), probing depth, DIMfacial (distance from the implant shoulder to the mucosal margin in the facial aspect), and width of the keratinized mucosa.
No patients had suppuration at the 10-year examination. Median probing depth showed a significant decrease over the 10-year period, from 4.5 to 4.0 millimeters. The remaining parameters revealed no significant changes over time.
Researchers noted significant changes in peri-implant bone levels during the 10-year period, but none of the implants demonstrated a continuous peri-implant radiolucency. Values at 6 and 10 years were much greater than those at 3 months, 1 year, and 3 years. The median peri-implant bone loss between the 1- and 10-year examinations was 0.35 mm.
Researchers found that 19 of the 20 implants (95%) had a detectable facial socket wall. Twelve sites revealed no facial socket wall at the future implant shoulder site, while the remaining 8 sites revealed a median thickness of 0.43 mm. The median facial socket wall thickness increased significantly from 0 mm at surgery to 1.67 mm at the 10-year examination.
Of the 19 implants, 15 (79%) had a positive facial bone wall value, with the peak of the bone wall being located coronally to the implant shoulder. The facial vertical bone loss of the facial bone wall was 0.02 mm between 6 and 10 years. The median peri-implant bone loss was 0.35 mm between the 1-year and 10-year examination.
Read the original article here.
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Tips for winning the battle against stress
Dr. Bill doesn’t want to go to work today. Things keep going wrong. The practice is always running behind. Patients get upset or walk out. One of his best employees left last month for another practice. She said she couldn’t take it anymore. Draining the last of his coffee, he hops in his car. He pulls into the parking lot and stares at his practice. He wishes he could go back home. Instead, he walks toward the entrance. Gripping the doorknob, he steels himself for another day. “Who knows? Maybe it’ll be a good one,” he thinks, ever the optimist.
This might sound like an exaggerated example, but nearly one-third of dentists (29 percent) are experiencing high or extremely high stress, according to the latest Dental Economics – Levin Group Annual Practice Survey.
“Dealing with high stress day in day out takes a physical, psychological and emotional toll” said Dr. Roger P. Levin in his Dental Practice Success article Winning the Battle Against Stress. “Fortunately, there are things you can do that can greatly reduce stress.” Read this article and more at ADA.org/DPS.
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Are your patients experiencing debonds, sensitivity or esthetic challenges? Are you really using the right cement for the right clinical case? If you are overwhelmed by all the cement choices available today, then visit www.cementationanxiety.com to get all of your cement questions answered and a cure for your cementation anxiety.
JADA+ Specialty Scans and JADA+ Scans
JADA+ Specialty Scans and JADA+ Scans are quarterly newsletters updating dentists on the latest research in selected specialties and disciplines in dentistry. ADA Publishing and the consulting editors from the represented specialties and disciplines aggregate and summarize research from previously published materials, each item attributed to its publication of origin. JADA+ Scan specialties and disciplines include endodontics, oral pathology, orthodontics, pediatric dentistry, periodontics, prosthodontics, radiology, cosmetic/esthetic and osseointegration. The ADA has engaged the specialty organizations in these areas as well as its own Science Institute and Division of Legal Affairs to assist with these newsletters. View past issues here.
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