Composite Veneers Vs Porcelain Veneers – Which one to choose?

Direct anteriors - Indirect anteriors
3 Oct 2017

Veneer is often today the method of choice in cases of anterior tooth reconstruction, due to the excellent esthetics, function (anterior and canine guidance, phonetics) and biological integration possibilities that it offers. This technique perfectly suits the trends that have dominated dentistry in the recent few years, towards reducing the amount of tooth preparation in restorative dentistry. 

Clinical success with porcelain veneers

Clinical success with porcelain veneers relies on several factors. These include the invaluable benefits of well-designed tooth preparation, precise veneer fabrication in the laboratory, and cementation in the rubber dam in accordance with strict adhesive procedures. 

A misunderstanding of porcelain veneering philosophy, meaning capabilities too,  leads to poor clinical results and the dissemination of poor opinions about the perishability of the veneers, among both dentists and patients. That is certainly a myth that does has nothing to do with well-prepared and cemented veneers, which seem to be more durable and esthetically pleasing than prosthetic crowns. Data from long-term clinical studies show that porcelain veneers have high clinical success. In a study conducted by Friedman, the clinician’s presented his observations of porcelain veneer failure patterns over a 15-year period. In all, 3 500 porcelain veneers were evaluated and the clinical success rate was found to be 93%.

INDIRECT PORCELAIN VS DIRECT COMPOSITE VENEERS
If the above mentioned requirements (for example, access to a good laboratory) cannot be fulfilled, the clinician should think about continuous hands-on training in order to perform feasible and repeatable direct composite veneers. 

The proper indication seems to be crucial. Bilaterally balanced occlusion and reasonable oral hygiene are important in the qualification process. 

There are several advantages of composite veneers, such as:
– Minimal invasiveness (in many cases “0” preparation)
– Maintenance (it is possible to repair the composite restoration in a very short time)
– Cost effectiveness (they are much cheaper)
– It is easier to perform direct composite veneer in the event of a single central incisor that needs to be veneered
– They are definitely recommended over porcelain for youngsters

In the Author’s experience, direct composite veneers behave much better functionally than porcelain when lower anteriors need to be veneered.
However, there are also limitations to the use of composite veneers, such as when upper anterior teeth need to be elongated significantly. In these cases, porcelain should be favored. Furthermore:
– It is relatively easier to perform porcelain veneers when many restorations need to be done
(eg. six or eight upper anterior teeth)
– In cases when we could expect composite discoloration (e.g. among sommeliers)
– In cases when we need to mask severe tooth discoloration (it is generally not easy but easier to perform in the laboratory)

The indications for composite and porcelain veneers are presented in Img. 1

A 31-year-old female patient presented at our clinic in order to be treated with porcelain veneers.
She was seeking to improve her smile, along with the shape and length of her teeth, but after oral examination and dental photos we convinced her of the necessity of undergoing an orthodontic treatment first.
She went through two years of orthodontic treatment and returned hoping for beautiful porcelain veneers… But after orthodontic treatment her smile looked nice to us, and we tried to avoid porcelain and tooth preparation. The patient appeared fixated on the idea, but we managed to convince her to avoid porcelain and go for no-preparation direct composite veneers instead.
The wax-up and silicone index confirmed that elongation of the central incisor could have an extremely pleasant effect on the patient’s smile. After rubber dam placement, four direct composite veneers were made, and the final result exceeded the expectations of both the patient and dentist.

The natural appearance of the characterized composite veneers can be seen in Img. 12-17.

Five years later, the patient revisited the dental office with a definite wish to replace the composite with porcelain. Although the composite resins behaved relatively well, the surfaces were a little worn as the patient cleaned her teeth with quite abrasive whitening toothpaste bought in the supermarket. In addition, she was concerned about some margin discoloration of the composite resin.
As the patient was a ”heavy-hand tooth cleaner”, she insisted on a restoration that would be more resistant to wearing and discoloration in the long-term.

Four porcelain veneers were planned for the upper anteriors.

 

PREPARATION
The preparation was obtained through the previous composite veneers, which served as the mock-up. Facial depth cuts of 0.5 mm were obtained, and incisal depth cuts of 1.5 mm. Then, a medium grit, round-ended, diamond bur was used to remove a uniform thickness of facial enamel by joining the depth-cut grooves.
During the preparation of the facial surface, the drill should be positioned with respect to the tooth anatomy, which in practice means three different drill angulations: buccal, gingival and incisal. Otherwise, the dentin can easily be exposed and consequently veneer adhesion will be compromised.
It is important to control the tooth reduction depth at different horizontal levels of the preparation. This should be accomplished by sectioning the silicon index. In this case, the space for porcelain veneer ranged from between 0. 3mm to 0.5 mm, and lithium disilicate porcelain (E -max) was used as the final restoration. 
The incisal space created between tooth structure and the final incisal outline of veneer should be 1.5-2.0 mm (incisal overlap). The frequently prepared palatal “mini-chamfer” should be replaced by a simpler one, a butt margin.  The use of a butt margin actually provides the margin of the restoration with a strong bulk of porcelain, instead of creating a thin marginal extension of ceramic (as with a palatal chamfer). Magne showed that high tensile stresses may be generated in the palatal concavities during functional loading, therefore palatal extension is not recommended.

IMPRESSION
A double mix impression was used; immediately after the thicker deflection cord is removed, a light-body impression material is injected into the sulcus and a tray loaded with a more viscous material is inserted.
Facebow registration, bite registration and opposite arch impression were obtained before temporary veneers with bis-acrylic composite (fProtemp, 3M) and silicone index were made.

 

 

IN-OFFICE CONDITIONING OF THE CERAMIC SURFACE

– Cleaning with 70% alcohol.

– Lithium disilicate ceramic (IPS e.max): apply hydrofluoric acid at 5 % and reduce the time of application to 20 seconds.

– Veneer rinsing with water spray for 30 seconds. At this stage, Magne recommends eliminating the white residues that are present on the veneer after acid etching, by placing restorations in 95% alcohol in an ultrasonic bath for 4-5 minutes.

– Drying with air spray for 20 seconds

– Silanization of the veneers:  the etched ceramic surface is covered with a few coats of the active silane solution. A heat source will significantly enhance the promoting effect of the silane, for example 2 min. of hair dryer application. 

– Adhesive system application: one coat of adhesive resin should be applied to the inner surface of the veneer, followed by gentle thinning with air; the adhesive resin placed on the veneer should never be light cured!

– The veneer should be protected from strong light sources.

 

 

CONDITIONING OF THE TOOTH SURFACE

– Patient local anesthesia (should be performed only after try-in, as the patient’s lips are needed for esthetic evaluation).

– Rubber dam isolation (with for example clamp no B5, B6 by Hygienic, or Ivory 212). In cases where two central incisor restorations are cemented, two veneers should be placed at the same time, in order to avoid any asymmetry. For that reason, the teeth can be isolated with modified B5 clamps.

– Meticulous tooth surface cleansing by micro-sandblasting with the finest sand (30 µm of aluminum oxide).

– Careful blow with air spray in order to remove all sand particles from the surface of the tooth.

– Veneer try-in with rubber dam isolation. If the clamp or rubber disturb prompt veneer placement, the rubber dam isolation needs to be corrected.

– Tooth conditioning: 20 s etching with 37% phosphoric acid (such as Ultratech, Ultradent)

– Precise rinsing and delicate air drying.

– Adhesive resin application and meticulous air spray thinning of the adhesive layer.

– Light-curing.

 

LUTING MATERIAL PERPARATION

– Composite resin is applied precisely to the whole inner surface of the veneer. Special attention needs to be paid to apply the composite to the approximal, curved surfaces.

– The restoration can be initially inserted and carefully pressed by fingertip, and gross excess is removed using an Fissura Instrument (LM, Style Italiano) in a cutting motion, parallel to the margin. Fingertip pressing needs to be repeated a few times in order to place the veneer perfectly on the prepared tooth. The procedure can generally last from one to five minutes, although unlimited working time is possible due to light-curing polymerization of the material.

– The complete and passive siting of the veneer is achieved when the finger pressure does not provoke any further protrusion of composite cement at the margin; the initial light-curing is performed (5 s) in order to stabilize the restoration.

– Final removal of the excess from the interproximal areas with dental floss. The floss should be move delicately in the incisal to gingival direction, then removed buccally in order not to displace the veneer.

– All margins are covered with glycerin gel (KY Jelly Personal Lubricant, Johnson & Johnson).

– Light-curing of the luting material (60 s from each of the side: palatal and facial: mesial, distal, gingival and incisal); The lamp should have light intensity greater than 850 mW/cm 2     
in order to be effective even through the layer of ceramic material.

– Removal of polymerized composite resin with scalpel no. 12.

– Polishing of the margin with the composite polishing flame (eg, Opti1Step Polisher 8000, Kerr).

 

In the cementation of the other veneers different strategies of tooth isolation can be utilized.

The proximal contact point and insertion possibility should always be checked before subsequent veneer cementation. In the event of the approximate surface blocking appropriate sitting of the veneer, 8 µm occlusal foil should be placed between tooth and porcelain veneer during try-in. If occlusal foil is in danger of tearing during removal through the contact point, delicate correction of the porcelain veneer with diamond polishing cups should be carried out.

 

Fig. 1

Img. 1 – Parameters for direct Vs indirect veneers

Fig. 2

Img. 1 – Smile of the patient before treatment

Fig. 3

Img. 2 – The photo of the teeth before ortho treatment

Fig. 4

Img. 3 – The situation after orthodontic tretament

Fig. 5

Img. 4 – The semi-profile smile of the patient after ortho treatment

Fig. 6

Img. 5 – The semi-profile photo shows that elongation of the central incisors is possible

Fig. 7

Img. 6 – The ortho retainer is transferred into the deprogrammer

Fig. 8

Img. 7 – The isolation of the maxillary anterior incisors before fabrication of the direct composite veneers

Fig. 9

Img. 8 – The silicone index was utilized

Fig. 10

Img. 9 – Thus palatal surfaces of the central incisors were obtained

Fig. 11

Img. 10 – After finishing the direct veneers of the central incisors, the same procedures were carried out for maxillary lateral incisors

Fig. 12

Img. 12 – The situation after fabrication of 4 direct composite veneers

Fig. 13

Img. 13 – Lateral view

Fig. 14

Img. 14 – Close-up of the smile with finished direct composite veneers

Fig. 15

Img. 15 – The patient’s smile with finished direct composite veneers

Fig. 16

Img. 16 – The close-up photo of maxillary central incisors covered by composite veneers

Fig. 17

Img. 17 – The final smile of the patient is harmonious with features of the face

Fig. 18

Img. 18 – Five years later, the patient revisited the dental office with a definite wish to replace the composite with porcelain. Although the composite resins behaved relatively well, the surfaces were a little worn as the patient cleaned her teeth with quite abrasive whitening toothpaste bought at a supermarket.

Fig. 19

Img. 19 – She was concerned about some margin discoloration of the composite resin

Fig. 20

Img. 20 – As the patient was a ”heavy-hand tooth cleaner”, she insisted on a restoration that would be more resistant to wearing and discoloration in the long-term.
Four porcelain veneers were planned for the upper anteriors.

Fig. 21

Img. 21 – The preparation was obtained through the previous composite veneers, which served as a mock-up. Facial depth cuts of 0.5 mm were performed, and incisal depth cuts of 1.5 mm. Then, a medium grit, round-ended, diamond bur was used to uniformly remove the facial enamel by joining the depth-cut grooves.

Fig. 22

Img. 22 – The proximal extension in order to avoid future discoloration at the margin area

Fig. 23

Img. 23 – The control of the volume of the prepartion with the silicone index

Fig. 24

Img. 24 – Finally the four maxillary incisors prepared

Fig. 25

Img. 25 – Ready for the impression with a double cord technique

Fig. 26

Img. 26 – 4 porcelain veneers prepared in the lab

Fig. 27

Img. 27 – After isolation of the teeth

Fig. 28

Img. 28 – Adjustment of the proximal surface of the veneers

Fig. 29

Img. 29 – Tooth conditioning: 20 sec etching with 37% phosphoric acid

Fig. 30

Img. 30 – Precise rinsing and delicate air drying.

 

Conclusions

In the Author’s experience:
– Both composite and ceramic veneers can result in excellent final esthetic outcomes, as seen in this case report.
– Composite veneers are faster to obtain, more cost effective, repairable, and – in many cases – can be easier to perform with no preparation.
– Porcelain veneers can represent a better option in more complex cases (http://www.styleitaliano.org/full-mouth-composite-rehabilitation), when teeth need to be elongated significantly, and when severe discoloration needs to be covered (http://www.styleitaliano.org/contraindicated-internal-bleaching-what-to-do).

Bibliography

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Zarow M: http://www.styleitaliano.org/contraindicated-internal-bleaching-what-to-do
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Friedman M.J. A 15-year review of porcelain veneer failure–a clinician’s observations.
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