DISCUSSION
The interest of a multidisciplinary care is to limit the dental
biological cost: the riziform tooth has a reduced dental support, the
orthodontic treatment and the analysis of the situation beforehand make
it possible to limit to the maximum the dental preparations, but also to
limit the periodontal biological cost, since the orthodontic treatment
can in certain cases avoid an useless periodontal surgery (35). We are
however aware that the realization of an impression on a multi-attach
appliance makes the reading of the plaster models difficult. Moreover,
it is important to note that the notion of ”beautiful smile” remains a
subjective notion depending on each individual. A study has shown that
the appreciation of a smile varies according to the age of the
evaluator. Older people are less fussy about black triangles than
younger people, as is the uncovering of teeth by the lips when smiling
(18). Some studies show an inter-sex difference on the judgment of a
smile, women seem more critical than men (37) while other studies show
that there are no inter-sex differences, especially concerning the
appreciation of the mesio-distal diameter of the maxillary lateral
incisors (38). In addition, overall, orthodontists seem more critical
(39) towards a smile than a general practitioner. And people in the
general population seem less critical than a general practitioner
(24,40). However, in another study, the notion of “smile arc” seems to
be evaluated identically between orthodontists, general practitioners
and the general population (41). For this, from an esthetic point of
view, it is important to focus more on the patient’s appreciation than
on our own personal appreciation as a practitioner, and to take into
account the differences in inter-individual appreciation (sex, age,
origin, etc) and especially to clearly define the objectives of the
protocol. The most conservative approach to correcting tooth shape is
direct resin composite bonding because it can be achieved without
removal of tooth structure. Recent esthetic composite resin materials
have similar physical and mechanical properties to that of the natural
tooth and possess an appearance like natural dentin and enamel. They
offer an expanded range of shades and varying opacities designed
specifically for layering technique whereas early brands of composite
resins offered only “body” shades and appeared dull and dense.
Treatment is usually completed in one appointment. In addition, direct
resin composite bonding treatment is less expensive compared with
ceramic veneers. In this case, we decided to set up a veneer on the left
lateral because of its shape and the high inter-proximal space to fill,
and to establish a direct resin composite on the right lateral because
of the low inter-proximal space. If a veneer was set up, it would have
led to unnecessary deterioration of the enamel.
Adhesive ceramic veneers constitute a minimally invasive therapeutic
approach and are able to replace defective natural enamel with a more or
less dandruff ceramic facet. This conservative technique, is very
suitable to treat many clinical situations while preserving the vitality
of the teeth. However the diagnosis and the indication have to be well
defined, and the protocol has to be strictly followed.
DSD and mock up play a crucial role in our protocol. Not only do they
facilitate the orthodontic finishing process (determination of the
position of the tooth concerned, provision of a better bonding surface
for the bracket), but they also guarantee an optimal final result and
help with the preparation of the tooth (36). In our clinical situation,
the M-D diameter of the laterals was within the norm compared to the MD
diameters of the centrals, therefore the DSD provided little additional
information. It is of particular interest in the case of severe dental
dysmorphoses that result in excessively high MD diameters of the
laterals, which inevitably lead to diastemas.
Furthermore, no study has dealt with the unsightly appearance of a
diastema between a canine and maxillary first premolar in comparison
with a diastema between a lateral incisor and maxillary canine. Despite
the efforts made to limit diastema, in some situations diastema is
unfortunately unavoidable, which can make the patient’s smile look
unsightly (26). Several indices have been developed to determine the
ideal mesio-distal diameters of the 6 maxillary anterior teeth, such as
the Mavroskousfis index, which states that the sum of the mesio-distal
diameters of the 6 maxillary anterior teeth is equal to the inter-alar
distance + 7mm. The Lee index states that the mesio-distal diameter of
the maxillary central incisor is equal to one quarter of the intercalar
distance. In our clinical case, the inter-alar distance is 46mm and the
sum of the maxillary inter-canal mesio-distal diameters is 44.6mm. If we
applied the Mavroskousfis index, this would result in an overly palatal
position of the maxillary sector and consequently a sub-nasal profile in
retro-position. The Lee index was not applicable in our clinical case
because the diameter of the central incisor was 8.2mm and the quarter of
the inter-alar distance is 11.2mm. For these reasons, we therefore
applied the rule of German et al. cited above.