Replacing Existing Veneers and Crowns in Dubai

Restorations are reassessed for a small number of recurring reasons, and nearly all of them are biological or mechanical rather than mysterious. Decay appears where a margin meets the tooth. A margin that used to seal no longer does, and the join can be felt with a probe or seen on a radiograph. Ceramic chips or fractures. A restoration debonds and comes away. The gum recedes and a margin line that used to sit hidden becomes visible. The bite loads some units harder than others. In an analysis of the reasons recorded for replacing 9,805 restorations in general dental practice, the clinical diagnosis of decay next to an existing restoration was the most common reason, followed by fracture of the restoration, with discolouration third for tooth-coloured materials in adults.^[1] Those were fillings rather than ceramic work, so the figures do not transfer across, but the three headings are the same ones that bring a veneer or a crown up for review.

Crowns have been surveyed the same way. When 92 general dental practitioners in the United Kingdom recorded the reason for every crown they provided over a twelve week period, 712 of the 2,164 crowns, a third of the total, were replacements of a crown already in place, and the most commonly recorded reason for replacing one was failure of the crown itself, at 27 percent.^[2] Replacement, in other words, is a normal part of the working life of a restoration rather than an unusual event.

For veneers, the longest published clinical series comes from a university clinic in Innsbruck, which followed 318 porcelain laminate veneers in 84 patients for a mean of just under ten years. Estimated survival was 94.4 percent at five years, 93.5 percent at ten years and 82.9 percent at twenty years. The most common single reason a veneer failed was fracture of the ceramic, which accounted for just under 45 percent of the failures recorded. Veneers on teeth that had lost their nerve failed significantly more often, an established clenching or grinding habit carried a 7.7 times greater risk of failure, and marginal discolouration was significantly worse among smokers.^[3] Those three findings are the ones that matter most at a reassessment, because they say that what the ceramic is bonded to, and what it is asked to withstand, shape the outcome at least as much as the ceramic does.

Gum recession deserves separate mention, because it changes how a restoration looks without anything happening to the restoration at all. A review of cross-sectional surveys reported that around 50 percent of adults aged 18 to 64, and 88 percent of people aged 65 and over, have at least one site with gum recession, that more than half the population has at least one site of a millimetre or more, and that both the presence and the extent increase with age.^[4] When the gum margin moves, a join that was designed to sit beneath it becomes a visible line. That is a change in the gum rather than a change in the ceramic, and what follows is often treatment of the gum rather than of the restoration.

Some people arrive with a clear clinical finding. Others arrive with something harder to say out loud: the teeth are technically sound, and they have never felt like theirs. The shade is brighter or flatter than expected. The shape is squarer, or longer, or more uniform than the face behind it. They look right in a photograph and wrong in a mirror. That is a legitimate reason to be assessed, and it does not need a medical justification attached to it.

It is worth being clear about what an assessment can and cannot settle. Some of what people dislike can be addressed in small ways: a contour reduced and repolished, an edge reshaped, gum inflammation treated so the tissue sits differently, or the natural teeth around a restoration whitened so the match reads better. Some of it needs the restorations remade, because shade and shape are built into the ceramic and cannot be argued with afterwards. And some of it turns out not to be about the teeth at all, which is worth knowing before anything is removed. Working out which of those you are dealing with is the purpose of the first appointment.

Nobody is asked to justify how they feel about their own smile, and nothing in the appointment is a judgement on the decision to have the work done in the first place. The subject is what is in your mouth now and what can sensibly be done with it.

A finding is not an instruction to remake something. Writing about the diagnosis of decay next to existing restorations, Mjör noted that these lesions are usually localised and limited, most often sitting at the gum-side margin, and that polishing may be sufficient where the defect is small. Where it is not, the defect can often be repaired instead of the whole restoration being replaced, which saves tooth structure and can extend the working life of what is already there.^[5] The same logic applies to a chipped edge that can be smoothed or built back, and to a margin that is stained rather than open.

Honesty requires a caveat. A Cochrane review that set out to compare repairing a defective resin composite restoration against replacing it searched the literature thoroughly and found no randomised controlled trials that answered the question at all.^[6] So the choice between repair and replacement is a clinical judgement made case by case rather than a matter settled by trial evidence. What it rests on is a straightforward biological principle: the option that removes less leaves more available later, which is a good reason to consider it first rather than last.

There is also a category that regularly gets missed, which is doing nothing. If the margins seal, the gum is healthy, the radiographs are clear, the bite is shared and the teeth beneath are comfortable, then well made restorations you are not especially fond of can reasonably be monitored rather than replaced, with a review interval and something specific to compare against next time. That is a real option, and it is sometimes the honest recommendation.

Every replacement cycle asks the same question of the tooth: how much of it comes away this time. The evidence on that is uncomfortable and useful. In a study of 1,337 decisions to replace existing restorations in back teeth, 70 percent of the recommendations resulted in a restoration covering a greater number of tooth surfaces than the one it replaced.^[7] Restorations tend to get larger each time they are redone. That is why a revision is planned around the smallest intervention that answers the actual finding, and why the question of whether something needs replacing at all is asked before the question of what it should be replaced with.

Where the margin sits matters for the same reason. A 26 year longitudinal study of a group of men with good to moderate oral hygiene compared surfaces whose restoration margins stayed more than a millimetre clear of the gum against surfaces whose margins ended up below it. It confirmed that margins placed below the gum margin are detrimental to gum and periodontal health, and found that the additional loss of attachment began slowly and became clinically detectable one to three years after the restorations were placed.^[8] In a revision, that is an argument for keeping a new margin at or above the gum wherever the case allows it, and for settling gum inflammation before anything definitive is made rather than afterwards.

The bonding matters as much as the shape. When an old restoration is removed, freshly cut dentine is exposed, and the biomimetic protocol is to seal that surface at the same appointment rather than leave it bare until the definitive restoration is fitted. A meta-analysis of 21 laboratory studies reported higher bond strengths to dentine when the sealing was done at preparation rather than delayed, both when tested straight away and after artificial ageing.^[9] That is bench evidence rather than a clinical outcome trial, so it is a reason for how the work is sequenced, not a claim about how long anything will last.

There is a limit to all of this, and it needs saying plainly. Sometimes the sound tooth left under a restoration is too little for a conservative option to be predictable, and sometimes that is not fully known until the old restoration is off. When that is the finding, you will be told, along with what the remaining alternatives are, including ones more involved than the one you came in expecting. Where those involve gum surgery or orthodontic movement, that part of the treatment is carried out by the specialist colleagues Dr. Khalid works with, while he plans the case, coordinates it, and carries out the restorative work himself.