Direct or Indirect?

Veneers are procedures sought for aesthetic reasons most of the time, not because they are necessary, so their prescription by the dentist should be carefully considered since the patient would be entering a lifelong cycle of treatments.

Regardless of whether a direct or indirect technique is chosen, it is important to keep in mind that when referring to veneers, one should always be referring to a minimally invasive treatment.

Here are some guidelines that the dentist should consider when deciding on the approach to a veneer case:

-Direct veneers require considerable skill from the dentist. In cases where the goal is to improve aesthetics (which is most of the case), skills such as mastering shape, color, and texture will determine whether the case is considered a success or a failure.

-If the dentist does not consider themselves to have a good tooth preparation technique, it may be preferable to opt for a direct technique to maintain adhesion to the enamel.

If a tooth is aggressively prepared and the restoration fails due to microleakage or debonding, there will not be many options available to the patient. If a porcelain veneer detaches continuously over a short period of time, the suggested treatment would be a full crown.

-In cases of dark teeth, dentists are tempted to make deeper preparations to create enough space for the material (porcelain/composite) to mask the color.

When a tooth involved in the aesthetic area is darker than the others, dentists should first attempt to whiten it to match the color with the other teeth before considering a more invasive preparation. If the tooth resists whitening, the recommended treatment in most cases is ceramic veneers.

- If the teeth to be treated have reduced enamel thickness, it is prudent to consider the direct, no-preparation technique. Veneers cemented to dentin are more prone to failure.

- Although dentin bonding is better than ever, enamel bonding remains the gold standard for all adhesive restorations. The best long-term retention for porcelain veneers occurs when at least 50% of the supporting tooth structure is enamel and all finish lines are on enamel.

- Less invasive preparation is indicated in cases where strength is a critical requirement. In fact, in cases where strength is a critical requirement, no preparation (direct) is the best option.

- Some authors have reported high failure rates when porcelain veneers are cemented onto teeth with resin restorations. The direct technique would be preferable due to its ease of repair.

- Stress in the orocervical area can cause microleakage fractures in cases where dentin is exposed. Pigmentation of the margins also increases where the preparation margin is located over dentin. Therefore, in similar cases, the direct technique may be preferable due to its ease of repair and resealing.

- The margins of restorations should be placed supragingivally whenever possible.

When veneers are placed on a patient, the volume of crevicular fluid production increases because the soft tissues have a defensive reaction to equigingival and supragingival margins, causing increased bleeding on probing. Furthermore, gingival recession is highly related to the latter two margins mentioned.

- Thin periodontal biotypes tend to migrate apically easily over time. Sometimes, even a single impression can cause gingival migration. This friability of the thin tissue results in an unattractive transition between the restoration and the tooth. Therefore, in patients with a thin biotype, direct restorations can be beneficial for the long-term success of the restoration, as direct restorations are easier to repair in the marginal area.

- Ceramics have shown less bacterial adhesion than other restorative materials. This is important for patients with less than optimal oral hygiene or those undergoing periodontal treatment, who are at high risk of relapse.

- Porcelain veneers excel at maintaining color and polish over time, making them suitable for patients with diets high in pigments, wine drinkers, etc.

- Direct restorations have good clinical performance and a good long-term success rate; however, due to their high maintenance requirements (polishing, adjustments), they should be indicated for patients with good oral hygiene habits and regular dental visits.

- Dentists must have a thorough understanding of the direct restoration materials they use, including proper polishing techniques. It is proven that there is a direct relationship between surface roughness and the amount of bacteria adhering to the material's surface. Furthermore, a well-polished resin is more aesthetically pleasing and less abrasive to the opposing tooth.

- An important point to consider is that micro-hybrid resins showed better marginal integrity than composite resins in a scientific study. Nano-filled veneers.

- We must never forget that porcelain is more abrasive to the opposing tooth than composite resin, an important factor to consider in young patients.

- In patients with malocclusions, it is wise to consider direct restorations due to their ease of repair, since it is said that occlusal forces increase microleakage and the formation of spaces in the cervical area, and can weaken the retention of the restoration.

- The flexural, fracture, compressive, and tensile strength of some composite resins are similar to porcelain veneers, but these, in turn, are less strong than "high-strength" ceramic systems.

- Because aesthetics are dynamic and constantly evolving, the direct technique should be considered in young patients due to its ability to be easily modified in the future.

- The cost of treatment should not be the deciding factor when prescribing the type of veneer. However, it can be a factor for the patient in making their decision.

If achieving the patient's expectations requires deep tooth preparation (dentin), it's best to consider orthodontic treatment before proceeding with aesthetic rehabilitation. Sometimes, the most ethical option is to forgo treatment altogether.

In conclusion, today we have access to a wealth of information, videos, and literature on materials, techniques, and protocols. We see cases daily on social media, cases that evoke a range of emotions, from "Wow, this doctor is amazing!" to "Wow, I still have so much to learn!"

Whatever your reaction, my advice today is, "Don't compare yourself to anyone." We are all experiencing a unique professional moment, and each process unfolds at its own pace.

My recommendation is to be consistent and resilient to setbacks. Don't hesitate to seek the opinions of ethical colleagues if you encounter difficulties with a case. Know your limitations, and if you choose to take risks, be prepared for failure.

I hope you find this information useful, best regards!

Dr. Marvin