Aesthetic Dentistry

Sir could veneer be successful treatment for this case?

Regards.

Regards.

case selection is very important for veneers. if there is less support for the veneers than they may come out very soon. From the images I feel that endo , followed by post and core ( at least for the patients left central) followed by a crown would be required.

regards,

veerendra

BRIEF HISTORICAL BACKGROUND
For more than 250 years, clinicians have written about the placement of posts in the roots of teeth to retain restorations.1 As early as 1728, Pierre Fauchard described the use of “tenons,” which were metal posts screwed into the roots of teeth to retain bridges.1 In the mid-1800s, wood replaced metal as the post material, and the “pivot crown,” a wooden post fitted to an artificial crown and to the canal of the root, was popular among dentists.1 Often, these wooden posts would absorb fluids and expand, frequently causing root fractures.2 In the late 19th century, the “Richmond crown,” a single-piece post-retained crown with a porcelain facing, was engineered to function as a bridge retainer.2 During the 1930s, the custom cast post-and-core was developed to replace the one-piece post crowns. This procedure required casting a post-and-core as a separate component from the crown.2 This 2-step technique improved marginal adaptation and allowed for a variation in the path of insertion of the crown.1

CAUSES OF POST-RETAINED CROWN FAILURE
The failure of post-retained crowns has been documented in several clinical studies (Figure 1).3 Many of these studies indicate that the failure rate of restorations on pulpless teeth with post-and-cores is higher than that for restorations of vital teeth.3

 Restorative failure of an all-ceramic crown on the maxillary right central occurring after endodontic treatment. A minimum of a 1 mm collar on sound tooth structure is required for a ferrule design.

 After determining the desired post channel length (one half to two thirds length of canal), the gutta-percha was removed with a series of pre-shaping instruments (Gates Glidden [SybronEndo]) (Rebilda post reamer [VOCO]).
Several main causes of failure of post-retained restorations have been identified, including: recurrent caries, endodontic failure, periodontal disease, post dislodgement, cement failure, post-core separation, crown-core separation, loss of post retention, core fracture, loss of crown retention, post distortion, post fracture, tooth fracture, and root fracture.4-6 Also, corrosion of metallic posts has been proposed as a cause of root fracture.7

A COMPARISON OF CURRENT POST SYSTEMS

. The channel preparation for a prefabricated fiber-reinforced post was performed using a color-coded drill (Rebilda post drill [VOCO]), establishing the desired intraradicular length and size for the selected post.

The pre-selected fiber-reinforced composite post (Rebilda post [VOCO]) was placed into the channel space. The coronal height was measured and marked with a diamond disc to the desired length. The post is cleaned with alcohol, silanated (Ceramic Primer [VOCO]) for 60 seconds, and then air-dried.

Today, the clinician can choose from a variety of post-and-core systems for different endodontic and restorative requirements. These systems and methods are well-documented in the literature.8-10 However, no single system provides the perfect restorative solution for every clinical circumstance, and each situation requires an individual evaluation.

Custom Cast Posts
The traditional custom-cast dowel core provides a better geometric adaptation to excessively flared or elliptical canals, and almost always requires minimum tooth structure removal.1 Custom cast post-and-cores adapt well to canals with extremely tapered canals or those with a noncircular cross section and/or irregular shape, and roots with minimal remaining coronal tooth structure.9 Patterns for custom cast posts can be formed either directly in the mouth or indirectly in the laboratory. Regardless, this method requires 2 appointment visits and a laboratory fee.

 A dual-curing, self-etch adhesive (Futurabond DC [VOCO]) was applied with an applicator (Endo Tim [VOCO]) to the base of the post space and air-dried. Any excess adhesive was absorbed with an endodontic paper point using a rapid
intermittent movement. A dual-cure, resin cement (Bifix QM [VOCO]) was injected into the post channel using an angled tip (Intraoral Tip Type 1 [VOCO]). It is important to remove the tip slowly while injecting, to prevent incorporation of air bubbles.

 The fiber post was immediately inserted into the post hole to the base of the prepared channel and light-cured from different positions for 2 minutes (7a). After polymerization, the fiber post was cut with a diamond bur to the predetermined length. Never use a serrated instrument or shears because this can damage the integrity of the post (7b).
Also, because it is cast in an alloy with a modulus of elasticity that can be as high as 10 times greater than natural dentin,11 this possible incompatibility can create stress concentrations in the less rigid root, resulting in post separation and failure. Additionally, the transmission of occlusal forces through the metal core can focus stresses at specific regions of the root, causing root fracture.11 Furthermore, upon aesthetic consideration, the cast metallic post can result in discoloration and shadowing of the gingiva and the cervical aspect of the tooth.

PREFABRICATED POST-AND-CORE SYSTEMS
An alternative consideration is the prefabricated post-and-core system. Prefabricated post-and-core systems are classified according to their geometry (shape and configuration) and method of retention. The methods of retention are designated as active or passive. Active posts engage the dentinal walls of the preparation upon insertion, whereas passive posts do not engage the dentin, relying instead on cement for retention.1 The basic post shapes and surface configuration are tapered, serrated; tapered, smooth-sided; tapered, threaded; parallel, serrated; parallel, smooth-sided; and parallel, threaded. While active or threaded posts are more retentive than the passive posts, the active posts create high stress during placement and increase the susceptibility of root fracture when occlusal forces are applied. Parallel-sided serrated posts are the most retentive of the passive prefabricated posts, and the tapered smooth-sided posts are the least retentive of all designs.2

Prefabricated Metal Posts
Traditional prefabricated metal posts are made of platinum-gold-palladium, brass, nickel-chromium (stainless steel), pure titanium, titanium alloys, and chromium alloys.2,4 Although stainless steel is stronger, the potential for adverse tissue responses to the nickel has motivated the use of titanium alloy.12 Also, contributing factors to root fracture such as excessive stiffness (modulus of elasticity)13 and post corrosion2 from many of these metal posts have stimulated concerns about their use.

Prefabricated Nonmetallic Posts

The nonmetallic prefabricated posts have been developed as alternatives, including ceramic (white zirconium oxide) and fiber-reinforced resin posts. Zirconium oxide posts have a high flexural strength, are biocompatible, and are corrosion resistant. However, this material is difficult to cut intraorally with a diamond, and to remove from the canal for retreatment.4 The fiber-reinforced composite resin post-and-core system offers several advantages: a one appointment technique, no laboratory fees, no corrosion, negligible root fracture, no designated orifice size, increased retention resulting from surface irregularities, conserved tooth structure, and no negative effect on aesthetics.

THE FERRULE EFFECT

The successful rehabilitation of any endodontically treated tooth using the post-retained system requires the consideration of one specific structural design characteristic: the ferrule effect. The stability of the crown is influenced by the preparation design for endodontically treated teeth. Preserving tooth structure during preparation is paramount in preventing stress concentrations at the cementoenamel junction of the endodontically restored tooth and provides resistance to tooth fracture. The completed crown preparation should have a ferrule design that encapsulates the endodontically re-stored tooth complex. This collar effect provides an antirotational feature for the stability of the crown. Clinical studies have demonstrated and confirmed the importance of this coronal tooth “collar” on the mechanical resistance and retention form of the endodontically restored tooth complex.14 The general guideline is a 1.0 to 2.0 mm preparation on sound tooth structure. Procedures that provide a shoulder on tooth structure, and an axial preparation on the core buildup, will have an insufficient ferrule design. In cases where there is insufficient sound tooth structure for a ferrule design, it is necessary to obtain this dimension through periodontal crown lengthening and/or forced-tooth-eruption procedures.

A team of German researchers has identified seven quantifiable parameters that can be used for the assessment of dentofacial aesthetics, according to a literature review that looked at how aesthetics can be evaluated in restorative dentistry (Journal of the American Dental Association [JADA], May 2012, Vol. 143:5, pp. 461-466).

Researchers from the Ruprecht Karls University School of Dental Medicine searched the Cochrane Library and Medline from January 1, 1975, to December 31, 2010, and selected 35 studies that focused on assessment strategies for dental professionals.

They were interested in doing this research because they were performing a number of aesthetic corrections on sound anterior teeth in the upper and lower jaw with direct resin composite buildups and wanted to measure the treatment outcome before and after the aesthetic correction, lead study author Cornelia Frese, DMD, told DrBicuspid.com.

"But we could not find a suitable tool for it," she said. "This is why I started to look over the literature, to find some quantifiable parameters."

A more systematic approach

The primary inclusion criteria for the studies in the review were intraoral and extraoral aesthetic assessment methods and indexes or rating scales evaluating aesthetics in restorative dentistry.

The researchers’ goal was to classify the different methods and extract quantifiable clinical parameters that might help in developing an index to be used for diagnosis, treatment planning, and outcome assessment.

“It is no surprise that not all the studies are in agreement.”
— Ronald Goldstein DDS
After reading the qualifying articles, the study authors sorted and grouped the studies into six categories according to their aesthetic assessment topic: golden proportion, soft-tissue measurement, smile and smile line assessment, orofacial indexes and scales, incisor proportion and angulation, and facial aesthetics. These categories included various aesthetic parameters.

Through their review, the authors identified seven parameters that are sufficiently and reasonably quantifiable: the smile line, lip line, incisal offset, location of dental and facial midline, incisor angulations and width-to-height ratios of the maxillary anterior teeth, gingival contour, and root coverage and papilla height.

"These parameters should be considered when providing dental treatment in the anterior area, as they allow for quantification and objective judgment," the study authors noted.

They hope that these findings might increase interest in a comprehensive dental aesthetic index.

"Although aesthetic feelings and sensations are influenced by sex, race, regionalism, and people’s self-perceptions, the seven specified parameters we identified are accepted widely in the West," the authors noted. "If these guidelines are used in careful agreement with the patient’s needs and expectations, both the dentist and the patient may achieve a satisfying aesthetical rehabilitation."

Computer-aided diagnostics

This is an important study because it attempts to summarize the 35 studies dealing with assessment of dentofacial aesthetics, according to Ronald Goldstein, DDS, one of the founders and past president of the American Academy of Esthetic Dentistry and author of Change Your Smile.

"It is no surprise that not all the studies are in agreement," he said. "Nor will they ever be."

However, studies like the ones described in the JADA article can be helpful, along with various tools and techniques employed by the dental profession, in working to achieve an aesthetic result pleasing to the patient, he added.

"One missing ingredient from the studies is the psychological interaction between dentist and patient, especially the demanding and picky patient and the patient who cannot even make a positive final decision about what he or she really wants," he said. "What I see in the future and one of the most certain predictions I make is that computer-aided diagnosis and treatment planning especially for aesthetics will be the norm within a decade."

At least one of the parameters identified by the JADA review has previously been recognized as a valid parameter for aesthetic evaluation.

A systematic literature review conducted by a German team reviewed the evidence on the validity and universal applicability of the smile line (European Journal of Esthetic Dentistry, Autumn 2011, No. 3, pp. 314-327).

"The smile line is a valid tool to assess the aesthetic appearance of a smile," concluded the authors of that study. "It can be applied universally as clinicians and laypersons perceive and judge it similarly."

Other studies also have identified aesthetic guidelines and standards that can be useful to clinicians during cosmetic restorative procedures (JADA, January 2001, Vol. 132:1, pp. 39-45). The authors of that study noted that the overall aesthetic impact of a smile can be divided into four specific areas: gingival aesthetics, facial aesthetics, microaesthetics, and macroaesthetics.

Further research is needed to establish and validate a common dental aesthetic index, according to the authors of this latest JADA review.

"At the moment, we are conducting a pilot study in our department to see if the identified parameters of this review are able to measure changes and differences in facial aesthetics, and if the measurements of aesthetics are objective, reproducible, and consistent," Dr. Frese said. "If we should succeed in our pilot study, these results might be beneficial for dentists in the future."

People would rather have a great smile than be in great shape.

The American Academy of Cosmetic Dentistry conducted a study regarding this issue and found an overwhelming majority opted for the smile.

There were 80 percent of American adults who said they would spend money to fix a flaw due to aging. Among these people, 62 percent said they would choose to improve the quality of their teeth while 48 percent stated that they would devote the money toward weight loss.

About 45 percent of Americans think a smile can successfully battle the effects of aging. The second choice for defying age was a person’s eyes, and 34 percent of the people believed that option. Only 10 percent of the people surveyed thought body shape could defy age, while 6 percent said hair and 5 percent said legs.

The study also showed that 54 percent of Americans older 50 thought that a smile could thwart the effects of aging. Just 38 percent of people ages 18 to 29 believe a smile can have that impact.

“A great smile is always in style, and these results prove it,” AACD President Dr. Ron Goodlin said. “Cosmetic dental professionals can rest assured that their services will be needed.”

The research for the study was done through Kelton Global and was scheduled in September, which is Healthy Aging Month. There were 1,018 adults who were 18 and older that took part in the study.

STUDY CONDUCTED FOR SELF ETCHING ADHESIVES ON INTACT ENAMEL
. Materials and Methods: labial surfaces of 20 caries free permanent upper central and lateral incisors were cleaned, sectioned of their roots. All specimens were mounted on acrylic block and divided randomly into two groups. In one group the application of self-etch adhesive was carried as per manufacturer’s instructions, composite cylinders were built, whereas in the other group, 37% phosphoric acid was applied before the application of self-etching adhesives. Then the resin tags were analyzed using the scanning electron microscope. Results: showed that when phosphoric acid was used, there was significant increase in the depth of penetration of resin tags. Conclusion: the results indicate that out of both treatment groups, pre-etching the intact enamel with 37% phosphoric acid resulted in the formation of longer resin tags and higher depth of penetration of resin tags of the Clearfil SE bond, which might have resulted in attaining higher bond strength of the Clearfil SE bond to intact enamel.