Effect of Increasing RVD on the smile
N.K. Mohindra BDS Edin 1969 – 22nd July 2021
ABSTRACT
In the 21st century, as dentists we should not just be concerned with the hard tissues of the smile as the smile is a dynamic three dimensional composition with a start, middle and an end. The most important elements of the composition are not just the teeth, but also include the lips, eyes and skin of the face. There is also a fourth dimension involved, which is the effect of ageing on the smile. As dentists, not only the hard tissues can be controlled, but with the use of the Oralift appliance [1], we can also affect the soft tissues.
Introduction.
The importance of the smile has been well documented not only from the perspective of attractiveness, but smiling is known to produce a wide range of health and emotional benefits [2]. If someone is seeking to achieve an improvement in their smile, their first thought would be to visit their dentist. Traditional methods to improve the smile included widening the arch with orthodontics [3] or veneers to reduce the buccal corridors. The maxillary incisor edges would be changed to follow the curvature of the lower lip. The size of the teeth would be changed with crowning to adhere to the rules of Golden Proportion [4,5,6]. The space between the upper and lower lip i.e. the smile window, could not however be changed. For example, if a patient had a very thin smile window, tooth display could not be increased. Ageing also affects the smile window. Maxillary tooth display reduces as we age and mandibular tooth display increases [7]. This can be partially explained by the downward migration of the soft tissues of the face, and the bony changes which occur on the face with ageing [8,9].
Recent work has shown that the soft tissues of the face can be changed by what we do in dentistry. Changing the vertical dimension can influence facial aesthetics and the lip position [10]. This would involve a full mouth reconstruction [11] or a lengthy orthodontic treatment, which are an invasive procedure. There is now a non-invasive method available to affect the soft tissues of the face. It involves wearing an appliance called the Oralift appliance. The appliance can be used to determine the correct occlusal vertical dimension when a permanent increase in OVD is needed. It can also be used when OVD is increased temporarily i.e. only when the appliance is in the mouth, in order to have an anti-ageing effect on the face and the smile window.
When the OVD is going to be increased permanently, the appliance must be worn at least 16 hours daily until new dentures have been fitted in the case of edentulous patients, or in the case of dentate patients, until full mouth reconstruction has been completed. When only the anti-ageing effect is required, the appliance is only worn for a maximum of two one hour sessions every third day and never at night. A lifetime regime of two months wear followed by four months rest is followed.
The Oralift appliance.
The Oralift appliance is based on the pivot appliance [12,13] which has been used in dentistry since the 1940’s. It evolved from the work done on edentulous and dentate patients where the OVD was increased permanently [14,15]. The appliance is composed of two materials, a thermoplastic material which when heated can be moulded to the patient’s lower teeth. The second part (the pivots ) which is made of a hard nylon material, is positioned on the lower posterior teeth. The pivots come in three sizes: 3mm, 5mm, 7mm thickness.
How it works.
When the appliance is moulded on to the lower teeth, the patient is encouraged to keep their lips together and not allow the top teeth to touch the top of the pivots. When the patient has the appliance in the mouth, the facial muscles need to adapt to let the jaw rest in a new position. This deprogramming of the muscles starts to occur as soon as the patient has the appliance in their mouth.
The muscles of the head and neck also adapt to the new position of the lower jaw. There is increased circulation, oxygenation and release of growth factors. This process of adaptation is similar to but not the same as exercise. As the volume inside the mouth changes, the breathing and swallowing muscles are also involved.
When the appliance is taken out of the mouth, the patient will experience an increase in freeway space, showing that the muscles have altered and adapted to let the jaw rest in a new position.
There is a paper which concludes that placing an appliance in the mouth does not change the freeway space[16]. The standard method of using the dots on the tips of the nose and chin method may not show this change in freeway space. However, if the patient is taught the principle of Oralift, which is that teeth should never touch the appliance, it will be apparent that the freeway space does change. This change in freeway space is a 3 dimensional change.
As the muscles adjust it is believed that tiny wounds occur in the muscle fibre followed by healing. The healing process continues for almost a year after the initial trauma [17]. Further research needs to be done to establish the exact mechanism of the changes taking place.
The Smile Window.
When looking at smiles, it should be remembered that smiles can be posed or spontaneous. There are differences between the two: in spontaneous smiles, the maxillary lip line is higher and premolar tooth display is increased by about 30% compared to the posed smile [18,19]. The posed smile can be a half or full smile. Both posed and spontaneous smiles are reliably repeatable.
The smile window is usually regarded as a classic oval or complex. In the classic smile, the upper lip is straight and the lower lip concave [20,21]. The incisal edges of the maxillary teeth follow the concavity of the lower lip. In the oval window, the upper lip is convex and the lower lip is concave. In the complex smile window. (check definitions in papers), the lips follow irregular lines.
When looking at pictures of the smile window, one should take into account the fact of head posture. If the head is tilted slightly backwards, the picture will show more gingivae than if the head is straight.
As dentists in the 21st century, we are able to control all elements of the composition: teeth, lips, skin, eyes and the shape of the smile window. We can also improve asymmetries of the face and reverse some of the effects of ageing on the face.
Teeth: we can change the shape, colour and the amount of gingival display. Changing the shape is usually done with veneers or crowns following the golden proportion rules. The teeth can be bleached to make them lighter. The gingival display is usually changed by periodontal surgery or by using Botox in the upper lip [22]. The Oralift appliance can also change the gingival display. This is illustrated in the photographs below. This change in the gingival display is due to the improvement in the facial muscles.
Skin: the skin plays an important part in the smile. The smile looks more attractive if the skin on the face is smooth and radiant. Many therapies purport to achieve this and nowadays dentists offer these: peels, Botox, dermal fillers. The skin is affected when the OVD is permanently increased or when using only the Oralift appliance. Photographs illustrate examples of lightening of the skin and reduction of pores and wrinkles.
Eyes: eyes form a crucial part of the overall composition of the smile. Oralift widens the eyes and improves the aged sunken look. Eyes look more vibrant.
Lips: lips can be enhanced with fillers but the vermilion show is increased when lip support is increased either with a wider arch size or through muscle hypertrophy which occurs when using Oralift.
Shape of the smile window: one of the problems with the smile is when a patient has a very narrow smile window and there is not much tooth display. The only way to increase the tooth display is to increase the size of the smile window and this can only be done by increasing OVD. but the appliance can be used to establish the new ovd and used to establish the centric relationship.
Asymmetries of the face: a smile will always look most attractive in a classic oval shaped face. Faces tend not to be symmetrical and when designing a smile, it is important to balance the asymmetries of the face. Oralift can reduce the asymmetries on the face.
Ageing and the Smile: As we age, tooth display changes when talking and smiling. Corners of the mouth do not lift as much when smiling. The eyes are more sunken in and appear duller. After using the Oralift appliance, these aspects are reversed by the improved tone of the facial muscles. The eyes will look bigger and the lower lip follows the curvature of the upper incisors. Lower tooth display will also decrease. Before carrying out irreversible changes to the teeth with crowns or veneers, it is essential to tone up the facial muscles with the use of the Oralift appliance.
The Oralift appliance does not need to be a stand alone treatment but can be used in conjunction with other modalities.
This is what can be achieved through dentistry.
This patient initially had her ovd increased. She gained so much confidence that she was prepared to undergo a makeover and now eleven years later, with regular use of the Oralift appliance, she still looks good for her age.
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