Dear Curious,The reason for the failure of the new bonding could be from a multitude of factors."Bonding" is a term used in dentistry to refer to the chemical bond that takes place between a composite resin restoration material, an adhesive system, and the enamel of the tooth. Not all of these materials are created equal, and some systems give a better, longer lasting, bond than others. This could be one consideration.Another consideration is the technique of the dentist. Achieving a long lasting, and well sealed bond depends on a variety of factors from preparation of underlying enamel, curing light type and time, complete dry isolation of the tooth, amount of adhesive placed and thinned appropriately, and the dentist's skill level.Yet another factor likely involved in this case is that you mention "we decided to a longinate." By this, I assume you meant that you and your dentist decided to make the incised edge of the tooth/teeth longer to achieve better proportions and esthetics. One must be careful when doing this, so as not to leave the bonded teeth in traumatic or hard occlusion. By this, I mean that when you bite your teeth together, if you are hitting with excessive force on the bonding material, and this force is not balanced or spread out amongst other teeth surfaces, this excessive force can weaken the bond and knock the bonding material off tooth. To avoid this problem your dentist must carefully plan the case, taking your individual occlusion into account, create appropriate lingual contours of the teeth, and carefully check and adjust your bite.That said, I generally recommend that for someone who wants both the best cosmetic results and longevity, to have the restoration done in ceramic/porcelain, rather than bonded composite resin. Each case is different, and you and your dentist should have a discussion on the best material and restorative approach for you, before you make a decision.Hope I could help,Courtney Kloberdanz, DDS
