From Volume 7, Issue 4, October 2014 | Pages 118-120
Tooth reshaping is becoming an integral part of orthodontic treatment to maximize the aesthetic outcome. The removal of incisor mamelons with Sof-Lex™ discs is a straightforward, easy and minimally invasive way of dramatically improving the appearance of previously unworn incisors. This method can be used during the finishing stages of orthodontic treatment.
Teeth may be reshaped for various reasons as a part of orthodontic treatment. Common examples of tooth reduction include removal of mamelons where lack of tooth contact has prevented significant abrasion and recontouring fractured, uneven incisal edges. Following trauma, central incisors may end up with an unfavourable width-to-length ratio, and this was discussed in a case involving ankylosed central incisors following avulsion and re-implantation.1 Other examples where teeth need reshaping include patients with congenitally missing lateral incisors where treatment results in canine substitution for the laterals.2 Tooth reshaping may also be required as mesial and distal enamel reduction (interdental stripping) as an alternative to the extraction of permanent units. It is a popular method for gaining space which allows alignment of irregularly positioned teeth.3,4
Excluding third molars, maxillary lateral incisors are the most commonly congenitally missing teeth with a reported incidence of 2%.5 When patients present with missing lateral incisors, historically the space was often opened up for placement of adhesive bridges or single-toothed implants. Recently, with the improvement of bleaching techniques, canine substitution increasingly forms part of the treatment plan. Contouring the canine appropriately and ensuring that the canine cusps are sympathetically reduced can give the illusion that they are lateral incisors.2
Reshaping enamel and tooth reduction can be carried out using a variety of techniques. Tuverson, in 1970, documented the possibility of recontouring a canine to an almost ideal lateral incisor shape with the use of diamond instruments.6 More recently, the use of abrasive discs, such as the Sof-Lex™ discs, mounted on a contra-angled handpiece, is recommended as the procedure of choice for routine enamel reduction. This technique was first described by Tuverson in the 1980s.7
Mamelons are morphological traits, present on the incisal tip of an incisor tooth when it first erupts through the gingivae.8 These developmental tubercules usually present as three rounded protuberances, which in most cases are worn down quickly with function. If an anterior open bite is present, however, mamelons can sometimes remain into adulthood. Prominent incisal mamelons are considered aesthetically unacceptable by some patients.
This article aims to show an example of using Sof-Lex™ discs to create a final aesthetic result at the end of orthodontic treatment.
A medically fit and well 12-year-old Caucasian female was assessed on the joint restorative/orthodontic clinic at Chesterfield Royal Hospital. She complained that her upper front teeth were ‘sticking out’ and that, particularly, she did not like the ‘bumps’ on the tips of these teeth as all of her friends had straight edges to their teeth.
The patient presented with a Class II division 1 incisor relationship on a Class I skeletal base with average vertical proportions (Figure 1 a–e). Her problem list included:
Because of the absence of incisor contact, there had been no wear of the upper central incisors whatsoever and, as a result, they had particularly prominent mamelons. The patient was of the opinion that these ‘bumpy edges’ to her front teeth were extremely unsightly.
The treatment plan formulated was:
The first stage of the treatment involved upper and lower fixed appliances to align the arches and to open up the space adjacent to LR3 for placement of a resin-retained bridge LR2 (Figure 2).
Once the orthodontic treatment was almost complete, due consideration was given to reshaping the anterior teeth.
The amount of tooth reduction was planned by initially marking the incisal edges with a permanent marker pen. This gave a clear demonstration of the new level of the incisal edges (Figure 3a). A discussion was then held with the patient and her parents showing them the proposed amount of tooth removal and checking that this would be to their satisfaction. Using a matt black background behind the upper front teeth when taking the photograph, the final appearance following tooth reduction can be simulated with reasonable accuracy (Figure 3b).
The Sof-Lex™ discs are supplied in two different sizes9 with four grades of abrasive surface for both the large and the small sizes (Figure 4). The discs clip on to a mandrel and are used sequentially, usually starting with the largest, coarsest disc to remove the bulk of the enamel. Both the wide bore aspirator and the air syringe are used simultaneously to keep the enamel cool during reduction. The second grade of disc is used for the final part of mamelon removal, and the final two discs (Figure 5a and b) are used to polish the enamel to regain the highly polished, smooth surface with which the patient is familiar. Digital images of the result can be taken and immediately shared with the patient during the procedure, to ensure that he/she is completely happy with the final size and shape of the teeth (Figure 6). Figure 7 a–e shows the final result and completed orthodontic treatment.
Sof-Lex™ discs are flexible polishing discs, with an aluminium oxide coating, designed to be used with a mandrel drilling system.9 Discs are available with different abrasive grades from coarse to superfine. In addition to Sof-Lex™ discs, stones such as greenstone, typically composed of silicon carbide,10 can be used for contouring and finishing surfaces where maximum abrasion is required, ie the occlusal surface or incisal edges. It can be difficult, however, to create a perfectly smooth finish and challenging to achieve refined tooth anatomy with these burs.10 Ultimately Sof-Lex™ discs are required to create the most superior aesthetic result.
Tooth recontouring and polishing may result in iatrogenic damage, such as increased sensitivity to hot and cold, pulp and dentine reactions, discoloration and caries,8 therefore the patient should always be warned about this in advance. In patients with large mamelons, carrying out this procedure over a number of visits may be advisable, to minimize post-operative sensitivity. The placement of a desensitizer or fluoride varnish, such as Duraphat®, to relieve dentine hypersensitivity11 after treatment, may be useful. By ensuring that abundant water and air cooling is employed, extensive enamel recontouring can be achieved with minimal pulpal or dentine reactions.8
Using the marker pen to allow patients (and their parents) to visualize the new incisal height can be beneficial in a number of clinical situations. In this case, the patient was shown the intended incisal edge by masking the mamelons so that approval could be sought. This allowed truly informed consent to be given for the procedure. In other instances it may be necessary to show patients with shorter incisors, as a result of excessive incisal wear due to bruxism or developmental abnormalities, the desired increase of incisal edge required to improve aesthetics. In this case, diagnostic wax-ups, marking this increased incisal length, can help simulate the orthodontic and restorative treatment plans.12
This paper has briefly reviewed the literature on tooth and enamel recontouring and has discussed some of the aesthetic challenges that can be overcome with tooth reshaping. The result achieved in this case was part of a planned multidisciplinary approach. A simple method using Sof-Lex™ discs to reduce the mamelons has enabled an excellent final aesthetic result to be achieved.
This case shows the importance of involving the patient throughout treatment. It also illustrates the use of minimally invasive techniques to provide aesthetic results and highlights the value of multidisciplinary care when treating patients.
