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JADA Specialty Scan - Cosmetic/Esthetic
Cosmetic/Esthetic - A Quarterly Newsletter on Dental SpecialtiesJADA

Patient perception and results of chamfer or feather-edge subgingival tooth preparations

Bleeding on probing is present around feather-edge margins, and more gingival recession is present around deep chamfer margins. Subgingival margins are technique sensitive, especially when dentists choose a feather-edge margin.

Those 2 conclusions are from a study published in the January/February issue of International Journal of Periodontics and Restorative Dentistry.

Researchers conducted a randomized clinical study with a 2-fold purpose: to measure the effect of a deep chamfer intrasulcular margin design on the periodontal soft-tissue parameters and compare it with a feather-edge subgingival tooth preparation and intrasulcular margin, and to see whether patients perceive any difference between the 2 in terms of esthetics and functional comfort.

Researchers prepared deep chamfer and feather-edge preparations for 58 patients randomly divided into 2 groups. Patients were nearly equally divided between men and women and ranged in age from 30 to 64 years. A total of 106 restorations were included in group 1 (deep chamfer margins) and 94 for group 2 (feather-edge margins). Clinical follow-up was conducted at 6 months.

Rounded shoulder and feather-edge burs were used for groups 1 and 2, respectively. In group 1, the facial restorative margin was first prepared equigingivally and then placed 0.5 millimeters below the gingival margin. Palatal margins were left equigingival and gradually deepend interproximally to 0.5 mm below the gingival margin.

In group 2, long flame-shaped diamond burs identified a flat subgingival area without a defined finishing line. The restorative margin was then finalized more coronally and positioned intrasulcularly 0.5 mm below the gingival margin. Patients were instructed to use a 0.2% chlorhexidine gluconate solution for 7 days until they could perform regular oral hygiene and returned 12 weeks later for the impression procedures.

At 6 months, patients answered a questionnaire using a visual analog scale (VAS) to measure satisfaction about esthetic and functional aspects of the restorations. They made a cross on a straight 100-mm line in which the left end read “not satisfied at all” and the right end read “completely satisfied.” The restorative margin position in relation to the gingival margin was classified as subgingival (not visible), equigingival (slightly visible), or supragingival (visible).

Researchers observed that 12.6% of the sites presented dental plaque, compared with 0 at baseline. Patients at baseline showed no gingival inflammation or bleeding on probing, while at 6 months 43.4% scored from 1 through 3 in the gingival index and about 39% had bleeding. Periodontal probing depth increased at mesial and distal sites and decreased at facial sites. Significantly more sites in group 2 had bleeding on probing (48.4%) than those in group 1 (30.5%).

Group 1 showed more recession with higher frequency of restorations with equagingival or supragingival margin position compared with group 2. The median VAS values for esthetic and functional satisfaction were 96.5 and 98, respectively. Statistically significant differences were present between the 2 groups in terms of patient perception of the esthetic result and function, with higher VAS median values for group 1.

“Potential difficulties might be related to subgingival feather-edge technique,” the authors noted, “as clinicians might not be able to see the finish line.” Therefore, they observed, “communication between clinicians and technicians must be clear to overcome the technician’s inability to visualize the exact position of the intrasulcular margin in the finishing area.”

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Consulting Editor: Luiz Meirelles DDS, MS, PhD
Director, Professional Products and Standards
ADA Science Institute

Patients’ esthetic expectations, satisfaction with complete dentures

Patient satisfaction exceeds expectations with regard to denture esthetics, and age and sex are not related to patient satisfaction. Men’s expectations are higher than women’s regarding denture esthetics and correlate positively with their satisfaction.

Those 2 findings are from a study published online January 31 in Journal of Prosthetic Dentistry.

Researchers designed the study to measure relationships between esthetic satisfaction of complete denture therapy and the factors of sex, age and esthetic expectations. They integrated data from 283 patients in 4 previous studies of complete denture satisfaction and performed a secondary data analysis. All of the studies recorded patients’ esthetic expectation and satisfaction scores using a 0 to 10 visual analog scale. They used the sign test to measure the difference between patient satisfaction and expectation. They used Spearman rank correlation to assess relationships among ordinal and quantitative variables. Differences among specified groups were analyzed using the Fisher exact test for nominal categorical outcomes, the Wilcoxon rank sum and Kruskal-Wallis tests for quantitative outcomes, and the Cochran-Mantel-Haenszel tests for ordinal outcomes.

A total of 52% of the sample was female. The average age was 58.4 years, the average esthetic expectation score was 9.0, the esthetic satisfaction score was 9.4, and the difference between the scores (satisfaction minus expectation) was 0.4. Researchers found a statistically significant difference in the numbers of male and female participants among the 4 studies. In the overall sample, satisfaction scores were significantly higher than expectation scores, although expectation and satisfaction were high.

Age and sex did not correlate with expectation or satisfaction score or with their differences for either men or women. The esthetic expectation score correlated positively with the satisfaction score for men but not for women. These bivariate relationships persisted after multivariable modeling of the esthetic expectation score.

Satisfaction scores after treatment did not show strong relationships with these factors. No significant difference in the distribution of esthetic satisfaction scores was found among studies after controlling for sex, and no significant findings for age, sex, or study were identified by means of multivariable modeling. These patterns emphasized the potential importance of covariate effects on the difference score, expressed as the esthetic satisfaction score minus the esthetic expectation score.

Study limitations included limited sample size restricted to a single region (southeast Brazil). The visual analog scale and methods of data acquisition may lead to patient confusion or pressure to provide higher scores. Data acquisition was not blinded, so the effect that the dentist-patient relationship had on the outcome or with patient responses on the survey remains uncertain. All measured variables relied on patients’ inherent characteristics and subjective interpretation of esthetics. In addition, researchers did not explore the effects of therapy choice and oral conditions.

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Since the introduction of IPS e.max, dentists and dental technicians worldwide rely on the highly resistant and highly esthetic lithium disilicate glass ceramic IPS e.max. Eleven years of consistent quality tests prove this ceramic has an average biaxial flexural strength of 500 MPa. Learn More.


Simple formulas for optimal tooth sizes

Simple formulas can determine optimal tooth sizes and create an esthetic guide worksheet to use with collaborating dentists and a sample written communication to accompany the completed esthetic guide worksheet. There is a method that allows for easy memorization of the formulas and determination of the best dimensions for teeth without using a calculator.

Research published in the December issue of American Journal of Orthodontics and Dentofacial Orthopedics addressed the challenges of designing esthetic and occlusally sound dentition. Factors include the frequency of anomalous and missing maxillary lateral incisors, attrition, trauma, transposition, erosion, and caries. Optimal esthetics and occlusion require correctly sized teeth that are in proportion to themselves and the other teeth.

Researchers found that roughly 80% of the population has anterior tooth widths that are within 0.5 millimeters of the research sample mean. Researchers further showed a significant correlation among the widths of the central incisors, lateral incisors, and canines. They rounded up the widths of the teeth to the nearest 0.5 mm, stating that smaller differences in tooth width size may become clinically undetectable to the human eye.

With these correlations, dentists can determine the optimal width of a missing or anomalous tooth. For the maxillary anterior teeth, given the width of the central incisor, the lateral incisor is 2 mm smaller and the canine is 1 mm smaller than the central incisor. This can be expressed with the following formulas:
            •     Maxillary central incisor (in mm) = Y
            •     Maxillary lateral incisor = Y – 2 mm
            •     Maxillary canine = Y – 1 mm

For the mandibular teeth, given the width of the central incisor, the lateral incisor is 0.5 mm larger and the canine is 1 mm larger than the central incisor. The following equations apply:
            •      Mandibular central incisor (in mm) = X
            •      Mandibular lateral incisor = X + 0.5 mm
            •      Mandibular canine = X + 1 mm

When several anterior teeth are anomalous, missing, or not ideally sized, the width of the mandibular central incisor can be used to calculate the ideal sizes of the other teeth because it is the least variable tooth of the 12 anterior teeth. Its width can be measured to establish ideal maxillary incisor widths. This is accomplished by recognizing that the maxillary central incisor is typically 3 mm wider than the mandibular central incisor. The formula is as follows: Y = X + 3 mm

Researchers noted that the mean size of a maxillary central incisor is 8.5 mm x 11 mm. “If you commit the average size of the maxillary central incisor to memory,” the researchers note, “all of the other widths are easy to calculate using the equations provided.”

The researchers also propose that a letter accompany the patient’s records, which reads in part, “When teeth require buildups, we open excessive space mesially and distally around the affected crowns … . The teeth can be built up to what you deem an optimal size in respect to the contralateral incisor or the adjacent teeth … . We have attached an esthetic guide tooth chart with our patient's widths recorded. This also includes research-based formulae to help calculate optimal widths of incisors and canines.”

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Conservative technique to repair class IV composite restorations

A new technique for repairing the facial surface of class IV composite resin restorations is similar to one used to replace the restorations and repair class IV composite resin restorations with unsatisfactory color. This technique is a viable alternative that preserves tooth structure, restores function and esthetics.

The findings are from a study published in the January/February 2017 issue of Operative Dentistry. The authors report a clinical case of a 22-year-old patient dissatisfied with the color of a right maxillary central incisor and left maxillary central incisor.

The palatal surface of the restoration in tooth no. 8 was discontinuous and featured marginal leakage. The restoration on the palatal surface of tooth no. 9 was complete and had adequate marginal adaptation. The replacement of class IV restoration in tooth no. 8 and the restoration repair in tooth no. 9 were proposed to the patient.

The authors removed the restoration in tooth no. 8 and obtained an elastomeric impression of the maxilla and mandible to make diagnostic wax-ups of tooth no. 8. They used a tapered diamond bur to remove the restoration in tooth no. 8 and prepare the facial surface of the restoration in tooth no. 9. They prepared the mesial surface to create space for the insertion of proximal artificial enamel. A design of the mamelons was made in the incisal region to create space to reproduce an opaque and opalescent halo. The authors prepared a mock-up to verify the correct composite resin color selection and was left in for 1 week as a temporary restoration.

Next, the surface of the old resin was sandblasted with aluminum oxide, and the enamel and resin were etched with phosphoric acid at 37% for 30 seconds. Silane was applied with a disposable brush and air-dried for 60 seconds. Adhesive was applied with a disposable brush. Care was taken to ensure adequate solvent evaporation before light curing for 20 seconds.

The stratification of the composite resin on tooth no. 8 included the use of high translucent resin EB1 to reproduce the palatal enamel, using a silicone guide obtained from the waxing. The incisal halo was reproduced with low translucent resin DB1. Low translucent resin DA1 was used to reproduce mesial third dentin, and low translucent resin DB1 was used to reproduce incisal third dentin and dentin mamelons. A translucent resin was used to reproduce the opalescent halo, which was lightly applied to the dentin mamelons. The facial enamel was finished with a thin layer of high translucent resin EB1. The restoration in tooth no. 9 was performed with low translucent resin DB1 to reproduce the dentin body and a translucent resin to reproduce an opalescent halo. The facial enamel was reproduced with a thin layer of high translucent resin EB1. Coarse removal of excess material from both restorations was done using a no. 12 sharp curved blade.

The finishing and polishing procedure was initiated with abrasive strips on the proximal surfaces. The facial surfaces were finished with sequential polishing disks of decreasing grit size. A carbide bur was used to remove excess resin from the preparation margin and to reproduce vertical texture. A felt disk with diamond polishing paste was used to perform the final polishing.

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‘See clearly now’ with OptraGate

OptraGate retracts the lips and cheeks evenly and gently, allowing more effective, relative isolation of the treatment field. The soft, flexible material adapts to the movements of the mouth in a controlled manner and is comfortable to wear for patients during the occlusion check or X-ray imaging of the teeth.

Watch video.

It’s time for spring whitening

During the winter months, many of us drink more stain-inducing beverages such as black tea and red wine. As springtime beckons, it’s the perfect time of year to offer your patients whiter, brighter smiles. The ADA’s brochure, “Tooth Whitening for a Better Smile” is the ideal aid to explain whitening toothpastes, home-use whiteners and in-office whitening. The brochure discusses if whitening is right for you, side effects, and the dangers of too much whitening. 

“Tooth Whitening” also includes dramatic before-and-after photos. The 6-panel brochure is available in packs of 50 from the ADA Catalog. A sample can be viewed here. To order, call 1-800-947-4746 or go to The title is available personalized as well. Readers who use the code 17406E before Sept. 30 can save 15 percent on all ADA Catalog products.


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Any statements of opinion or fact are those of the authors and do not necessarily reflect the views of the American Dental Association. Neither the ADA nor any of its subsidiaries have any financial interest in any products mentioned in this publication. Any reference to a product or service, whether in advertisements or otherwise, is not intended as an endorsement or as approval by the ADA or any of its affiliated organizations unless accompanied by an authorized statement that such approval or endorsement has been granted.

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