Cosmetic dentistry is a science. Like any other science, it never reaches a final state of wisdom. Whether it is a smile design, extreme makeover, or a smile makeover, new dental techniques and dental materials are continuously being introduced, tested, and discussed in the dental literature. Cosmetic dentists do not test new dental products or dental techniques on their patients. They study and verify the quality and applicability of a "new" technique in peer-reviewed scientific publications in dental journals. Cosmetic dentists often struggle to weed out the unimportant from the important when reading scientific literature. However, it is necessary to continuously review the latest dental techniques and materials critically to ensure that cosmetic dental practices provides the best possible care for their patients.
While the information you find on this page is still valuable information, we will now start updating our news about all aspects of cosmetic dentistry on our blog. There you will have the opportunity to ask questions or comment about any topic.
Most recent updates:
- Studies about the Longevity of Porcelain Veneers
- Have you ever heard of “Vertical Dimension of Occlusion?”
- How does nature establish and maintain VDO?
- Great News for Cosmetic Dentists - Streptococcus A12
- Cosmetic Dentistry has some Risks
- Blood Lead Levels Associated with Dental Caries
- Four to Nine Pounds of Lipstick in a Lifetime
- Obesity Related To Periodontal Disease
- Bad Breath - There Is Effective Help Now
- Black Tea May Help Fight Oral Disease
- Dentists Yield on Mercury in Fillings
- Smoking During Pregnancy Increases Risk Of Cleft Lip & Palate
- True Regeneration Of Diseased Gums?
- Cosmetic Dentistry Changes Lives
- Worn teeth
- Lumineers - What are they?
- Restoring Teeth Back to a Healthy State - With "Intensive Care" for the Dental Pulp
- The Gingival Smile Line?
- True Periodontal Rehabilitation - A Future Pillar of Cosmetic Dentistry
Great News for Cosmetic Dentists - Streptococcus A12
A microbiological natural enemy of Streptococcus Mutans, the dental-caries producing strain of oral bacteria, has been discovered. A12 neutralizes an oral acidic environment by metabolizing arginine. It also competes with and kills Streptococcus Mutans when placed together on biofilms. This is great news also for cosmetic dentists, because a healthy oral environment is a prime prerequisite for any smile rejuvenation.
References:
Xuelian Huang et al. Characterization of a highly arginolytic Streptococcus species that potently antagonizes Streptococcus mutans. Appl Environ Microbiol 2016 Jan 29; 82(7): 2187-201.
Cosmetic dentistry has some risks
Cosmetic dentistry cannot be compared with a simple haircut, a manicure, or a make-up.
Most of the procedures that a cosmetic dentist performs are irreversible and have a large impact on the function of your mouth. The outcome is not just aesthetic, it also needs to be fully integrated into the several functions that your mouth fulfills.
One of them is the chewing function. Among cosmetic dentists, it is called 'dental occlusion.' It deals with the way your teeth meet when biting or chewing. Cosmetic dentistry has become so complex that it cannot be delivered anymore without addressing the subtleties of occlusal function. Porcelain veneers or porcelain crowns that have been fully integrated into the basic functions of your mouth will be long-lasting and give you an improved quality of life. Just a shoe that fits is comfortable, right?
Cosmetic dentistry includes varying elementary aspects, such as marginal integrity, surface glaze, envelope of function, anterior guidance, lip-closure path, centric relationship of the jaws, and much more. You just have been given a multitude of dental terms that you may not be familiar with, to underscore the fact that your cosmetic dentist has to establish a variety of prerequisites prior to placing porcelain veneers or other cosmetic dental solutions.
If you have any questions regarding these, please feel free to contact Dr. Rabanus via e-mail at peter.rabanus@gmail.com. He will gladly give you a private consultation in any aspect of cosmetic dentistry to make your choice regarding your own teeth more educated and more predictable to you. Nothing is worse than unrealistic expectations and disappointing outcomes. You deserve a beautiful smile that is based on sound functional axioms and technologies. Only then will you be able to enjoy your new smile for many years to come.
Blood Lead Levels Associated with Dental Caries Children exposed to environmental lead may be more likely to develop caries than children who are not.
The Journal of the American Medical Association published a study that examined the relationship between blood levels and dental caries in more than 24,000 children.
The study revealed that for every 5 micrograms-per-deciliter increase in blood lead levels the rate of caries increased by 80%.
The study helps explain the disproportionately high rate of caries among inner-city children. The researchers conclude that changing diets may not be enough to prevent dental caries to occur. Improving oral hygiene habits and increasing fluoride exposure of inner-city children may be necessary.
Four to nine pounds of lipstick in a lifetime. According to a report in Glamour magazine, the average woman consumes four to nine pounds of lipstick in her lifetime.
A lipstick is an inexpensive luxury that anyone can indulge in. Even at times of economic crisis, a lipstick is an indispensable item. When food and other daily necessities were difficult to find, women still found money to color their lips to boost their morale. Just the shopping for a lipstick in a luxurious atmosphere allowed them to daydream and to feel pampered. Feelings of confidence and security were nourished by spending a little more than for a drugstore brand and gaining ownership of the crown jewel of lipsticks. High-end brands can cost more than $25.
Even women who don't wear makeup wear lipstick. More than mascara and eye shadow, lipstick is loaded with meaning and steeped in symbolism. The colors and shapes of painted lips make their own statement. At times it seems that the scrumptious emollient of women's lips carries their words to a different dimension. The darker varieties may even create the illusion of whiter teeth.
Obesity Related To Periodontal Disease A study found that overweight people with high insulin resistance were more likely to have severe periodontal disease.
Bacteria from gum disease may interfere with fat metabolism, leading to elevated low-density lipoprotein cholesterol and total cholesterol.
Obesity is related to gum disease through the pathway of insulin resistance, which is a condition in which the body does not respond well to the action of insulin.
We see a relationship between obesity, insulin resistance, and periodontal disease in a large population. This relationship is important because obesity is an important risk factor for Type 2 diabetes and heart disease. It is possible that periodontal disease increases the likelihood of their manifestation.
Bad Breath - There Is Effective Help Now. Zinc Chloride Based Mouth Rinses reduce malodor through elimination of volatile sulfur compounds.
Halitosis is defined as offensive odors emitting from the mouth. About 40 million Americans suffer from chronic oral malodor. Oral malodor is caused in over 90% of patients by retained foods, which are high in sulfur containing amino acids (i.e. meat and fish). Odors from volatile sulfur compounds (VSC's) are produced through a putrefactive action of microorganisms on tissue.
Oral malodor can be physiological or pathological. Physiological halitosis is temporary and may be associated with age, hunger, morning breath, menstrual cycle, or drug use. However, halitosis may have more than just social consequences. It may reflect serious local or systemic conditions including diabetes, gastric ulcer, hepatic failure, or tumors of the respiratory tract. Additionally, medications can contribute to halitosis by causing dry mouth. This eliminates the natural moisturizing function of saliva in the mouth.
Most commercial mouth rinses have only masked odors and offered short-term relief. However, recently developed mouth rinse containing zinc chloride have been shown to be very effective against malodor. Zinc rinses are found to reduce oral VSC's for over three hours significantly. The zinc ion functions as an odor inhibitor by preventing disulfide group reduction to thiols and by reacting with the thiol groups in VSC's. This converts them to non-odorous substances.
Ask your dentist.
Black Tea May Help Fight Oral Disease. Drinking black tea may help prevent caries and periodontal disease, said researchers at the American Society for Microbiology.
Chemical components in black tea called polyphenols suppressed the growth of caries-causing bacteria in plaque and reduced acid production levels. The polyphenols also inhibited glucosyltransferase (an enzyme produced by bacteria) and prevented the formation of the matrix material that dental plaque uses to adhere to tooth surfaces. Researchers also found that the size and stickiness of dental plaque were reduced because certain bacteria lost their ability to form aggregates with other bacteria when they were exposed to black.
Dentists yield on mercury in fillings State board agrees to cite experts' concerns
Kelly St. John, Chronicle Staff Writer
(August 4, 2001)
Oakland - In a surprise turnaround, a skittish California Dental Board shied away last night from a controversial fact sheet playing down the risk of mercury in dental fillings.
The board, under pressure from state lawmakers, instead asked its staff to revise the document to note that some experts think "silver" fillings pose risks to consumers. Silver fillings are about 50 percent mercury by weight. "Basically, we're saying there's some difference of opinion," Dr. Kit Neacy, president of the board, said after the meeting in Oakland. The session drew two dozen speakers, most of them adamant that asthma.
The board's unexpected move was made after intense pressure from state legislators who want to dissolve the dental board for a host of reasons, including not drafting for nearly a decade an acceptable mercury warning sheet.
The fact sheet was required by a 1992 law but never implemented to the satisfaction of state officials. It is designed for dentists to use when they speak with patients about what materials are used in fillings, including amalgam -- which refers to alloys of mercury, porcelain and resin.
Advocates were pleased by the results of the meeting, which at one point became so heated that nervous state officials summoned a dozen police and California Highway Patrol officers to stand by.
"We've made a huge step in recognizing the toxicity of mercury," said Charles Brown, a Washington, D.C., lawyer who is suing the and California dental associations. "At last, the board seems willing to say the M word." On its own, critics say, mercury is a toxic poison that may cause developmental and neurological problems, especially in children and pregnant women.
But the American Dental Association contends that the fillings are safe because mercury is combined chemically with other elements to form an alloy.
Some dentists compare it to chloride and sodium, both elements that harm humans on their own but form benign sodium chloride -- salt -- when combined.
Mercury vapors do escape during normal chewing and brushing, but not at a harmful level, according to the American Dental Association.
"There is no sound scientific evidence supporting a link between amalgam fillings and systemic diseases or chronic illness," ADA President Dr. Robert M. Anderton said in a written statement.
Others aren't convinced.
"If you have amalgam left over (after filling a cavity), there's only two things you can do," said Dr. S. Ward Eccles, a dentist from Livermore. "You can put it in a toxic waste dump, or you can put it in the next tooth. Something's wrong when those are the only two choices."
Consumers for Dental Choice have sued the American Dental Association, saying it is deceiving the public by supporting the use of mercury in fillings when mercury's use is being limited in other products, such as thermometers and blood pressure gauges.
After the state dental board canceled a June meeting that would have dealt with the mercury issue, state Sen. Liz Figueroa, D-Fremont, initiated a drive to purge the 12-member board, which licenses and disciplines the state's 30, 000 dentists.
"I don't think they take the whole responsibility seriously," she said. "They've delayed the process for over 11 years."
Smoking During Pregnancy Increases Risk Of Cleft Lip And Palate
A study on data by the Centers for Disease Control and Prevention's National Center for Health Statistics found that women who smoke during pregnancy are 50 to 78 percent more likely than non-smokers to give birth to babies with cleft lips and palates.
Cleft lips and palates are the fourth most common congenital birth defect and affect about one in 700 newborns.
Mothers who smoke 10 or fewer cigarettes per day increase the risk of their babies' developing cleft lip or palate by 50%. Those who smoked 11 to 20 cigarettes per day increased the risk by 55%. Mothers who smoked more than one pack per day raised the risk by 78%.
These findings reinforce the importance of educating women to not smoke while they are pregnant.
True Regeneration Of Diseased Gums?
Periodontal disease is an infectious disease affecting tooth-supporting structures. It results in color changes of the gingiva, periodontal pocket formation, bleeding, loss of attachment between the root surface of a tooth and the surrounding tissue, increased tooth mobility, and - of course - bad breath.
Until today, the attachment loss caused by the disease could only be halted. A reversal to its natively healthy state has practically been unsuccessful. In addition, even when healthy periodontal tissue is established, the results are often non-aesthetic. The healed tissue frequently displays visible defects due to the removal of infected and inflamed tissue. Therefore, a true regeneration of periodontal tissues has remained unsuccessful.
Recent research instills some hope that in the near future dentistry will be able to fully reestablish lost periodontal structures as they were initially formed during tooth development in children.
How is this possible?
The embryological development and differentiation of human tissue, such as our liver, brain, and teeth with their surrounding structures is directed by a complex exchange of messenger molecules between different cell populations. These molecules, produced by one cell, are recognized by another cell and in turn induce a functional change and the production and release of new messenger molecules. All this is very complex and fascinating and research is discovering new interactions every day.
One of the messenger molecules directing tissue formation during tooth development is called "Enamel Matrix Protein". It is one of many. However, research has demonstrated that this protein by itself sets in motion a series of events that lead to true periodontal regeneration. More clinical research is needed to optimize the procedures that will help establish an environment that mimics natural tooth development as it takes place during childhood.
Cosmetic Dentistry Changes Lives
American Academy of Cosmetic Dentistry, Madison, WI
Cosmetic dentistry is the field of dentistry dedicated to the art and science of enhancing a person's smile and oral health. Trends show that cosmetic dentistry goes further than teeth whitening- it changes people's lives! "As a cosmetic dentist, I feel I am changing lives, one smile at a time. Many of my patients now have the confidence to pursue paths that seemed unreachable before," commented a doctor from Sun Valley, Idaho, who is Accredited by the AACD. The AACD and its members are committed to improving Americans' smiles and their self-esteem.
The benefits of Cosmetic Dentistry were documented on the Discovery Channel program, "The Cutting Edge," in Fall 2000. One case involved a 39-year-old, Idaho horticulturist, John Olsen, who felt hampered socially and professionally by his irregular teeth. "I had no self-confidence, and without that, you don't try to do things because you believe you can't." Four procedures that took six weeks to complete gave John a full, attractive smile.
"I cried. I thought, oh my God they are gone, the plague has finally gone," Olsen exclaimed, emotionally taken by his new lease on life.
Worn teeth
Many patients have worn teeth at various stages. They often seek a cosmetic dentist to address aesthetic concerns regarding their smile. It may not be as simple as most patients expect.
Attention has to be given to the reasons why the wear of the teeth has occurred. If this step is ignored, the prognosis of any cosmetic dentistry will be questionable and the patient may end up wearing his new teeth the same we he did his natural teeth, or he may experience discomfort of his masticatory apparatus. Porcelain restorations may break. The jaw muscles may feel tired easily. The new teeth may feel unnatural.
Every patient has different requirements when addressing a worn smile and/or chewing surface. Often, he will need a night guard to protect his newly designed teeth. However, in some cases the new tooth design itself may serve as a contact surface that relaxes the chewing muscles the same way as a nightguard would do.
Studies about the Longevity of Porcelain Veneers
Many patients have asked us how long porcelain veneers would last. This is a very important question considering the cost of a full set of porcelain veneers. Fortunately, we have a lot of data about the life expectancy of porcelain veneers. Many studies have described their survival rate over various time spans. We will publish a few of the most important articles about this aspect of cosmetic dentistry in this section.
One study reports on a 6-year experience with Empress porcelain veneers. Of a total of 83 anterior veneers that were placed in 21 patients, only one failure was recorded, resulting in a success rate of 98.8%. The study described in detail what clinical procedures and laboratory techniques through were applied. In addition, the authors presented one clinical case is presented to illustrate the results obtained with their techniques.
You can find out more about it by reading the publication: M Fradeani. Six-year follow-up with Empress veneers. Int J Perio Rest Dent, 1998; 18(3): 216-225.
Another study reports a 98.4% survival rate of laminate veneers. A total of 186 veneers were placed by a single operator in 61 patients. The author concluded that porcelain veneers are a reliable and effective method to aesthetically enhance anterior teeth.
You can find out more about it by reading the publication: GA Aristidis. Five-year clinical performance of porcelain laminate veneers. Quintessence Int, 2002; 33(3): 185-189.
The authors of a review article conclude that etched porcelain veneer restorations have proven to be a durable and aesthetic treatment modality within the 25 years prior to the study (published in 2007). The authors attribute the success to great attention to every step of this important aspect of cosmetic dentistry. They discuss possible failures due to the lack of meticulous attention to every detail and underline the need to understand every new product and method to ensure continued success of this modality.
Please read the following publication if you desire to learn more: JR Calamia. Porcelain laminate veneers: reasons for 25 years of success. Dent Clin North Am, 2007; 51(2): 399-417.
One study was evaluating the survival rate of 304 feldspathic porcelain veneers of up to 16 years. The tooth preparations were designed with chamfer margins, incisal reduction, and palatal overlap. The cumulative survival for the veneers of this study was 96% +/- 1% at 5-6 years, 93% +/- 2% at 10-11 years, 91% +/- 3% at 12-13 years, and 73% +/- 16% at 15-16 years. The drop in survival between 13 and 16 years was the result of the death of a patient and the low number of veneers in that period.
D Layton. An up to 16-year prospective study of 304 porcelain veneers. Int J Prosthodont, 2007; 20(4), 389-96.
As you can see already by this small selection of publications, porcelain veneers are a safe and permanent treatment modality of cosmetic dentistry. We will continue to publish more articles about efficiency and longevity of porcelain restorations in this section. I will alert you on my Facebook page or on my Instagram Page about any updates.
Have you ever heard of “Vertical Dimension of Occlusion?”
There are terms in dentistry that may have never crossed any of the myriads of your communications in your life. However, it is a very important term in the field of dentistry. While you may not be aware of it, it very well may determine the exact outcome of your cosmetic dentistry or porcelain veneers.
What is the Vertical Dimension of Occlusion?
Occlusion is simply the relationship of the upper and lower jaw when the upper and lower dental arches touch each other. Occlusion natural occurs during chewing and swallowing.
This dental occlusion has horizontal and vertical dimensions. Together they create a three-dimensional space of function and specific jaw positions.
The vertical dimension develops during craniofacial growth in the adolescent and remains fairly stable throughout an entire lifetime. Craniofacial morphology, growth, and dental form are primarily accountable for the variations in dental occlusion (Moyers RE 1977, Laverne J 1985). However, maintenance of the VDO is related to the interaction of environmental factors and the dynamics of neuromuscular function during the aging process. When teeth are heavily worn through mechanical attrition, abrasion, or erosion (caused by acids), they either maintain the vertical dimension of occlusion or the combined height of maxilla and mandible by compensatory growth of the tooth-supporting alveolar bone and its gums and periodontal structures. This may lead to a gummy smile. In some instances, the vertical dimension is simply lost, leading to a premature aging of the face. This is more common after tooth loss.
A dentist has to determine, whether a patient seeking cosmetic dentistry has lost any of his vertical dimension of occlusion or whether there has been any compensatory growth. This is the very elementary datum that any treatment plan needs at its foundation. It is like surveying the terrain before building a house.
The determination of the state of the vertical dimension of occlusion (VDO) in a patient who seeks rehabilitation of his smile determines what can be done to restore teeth that have prematurely aged due to loss of tooth structure.
While the human face has been shown to be very adaptable to any changes of the VDO (Rivera-Morales 1992), this is not the main consideration when changing it. The cosmetic dentist simply looks at someone's smile to obtain an indication whether any changes of the VDO are required. Things like incisal-edge position in relationship to the lower lip, overjet, overbite, and the upper gingival architecture in relationship to the upper lip during a smile and speech are the prime considerations for designing a smile. One then determines how these parameters can be optimized by either increasing the VDO or by other treatment modalities such as crown lengthening and orthodontics.
(To be continued)
How does nature establish and maintain VDO?
The VDO and the vertical dimension of the face are influenced by environmental factors during cranial growth. The upper respiratory system has a role in the development of the vertical dimension of facial structures. The maxillary sinuses are part of that system and control the temperature of the inhaled air and pneumatize. Airway obstruction has been shown to interfere with normal facial skeletal growth.
Embryology is a very exciting field, because it explains how cellular subpopulations interact with each other and build structure, dimension, and form of all parts of a human body. The VDO is primarily influenced by the interaction of certain cranial cell populations that lead to the formation of teeth, the surrounding bone, and the periodontal tissues, which effects the development of vertical height of both, the maxillary and the mandibular tooth-embedding bone structure (“alveolar bone”).
Once cranial growth is complete, the VDO is determined by adaptive responses of the jaw joint (TMJ), the periodontium, and the way teeth contact. TMJ and peridontium respond to acute challenges. They respond to acute micro- and macrotraumas with reversible fluid shifts of the extracellular matrix. Continuous structural strain activates certain cell populations that lead to changes of extracellular matrix proteins and tissue morphology of cartilage and bone. Stress on body structures can go beyond their adaptive capacity, which causes them to degenerate. This may lead to a change of the VDO. However, therapeutically changed VDO has been observed to reverse to its original natural height after years of observation. This aligns with the fact that teeth adapt to the vertically positioned mandible as dictated my the musculature, not vice versa.
One study (Rickets et al) showed that lower facial height in adults stayed constant throughout life. Another study (McAndrews et al) demonstrated that in more than 1,000 orthodontically treated patients the VDO reverted back to the original dimensions within one year. This finding is very significant, because it indicates that the VDO can be opened or closed without doing any harm as long as simultaneous equal-intensity contacts are established in centric relation (CR).
References:
- Ricketts RM et al. Orthodontic Diagnosis and Planning: Their Roles in Preventive and Rehabilitative Dentistry. Denver, CO: Rocky Mountain Data Systems; 1982; 1: 15-147.
- McAndrews I. Presentation at: The Florida Prosthodontic Seminar; 1984; Miami, FL. (Referenced by Dr. Peter Dawson, St. Petersburg, Florida).
- Hylander WL. Morphological changes in human teeth and jaws in a high attrition environment. In: Dahlbert AA, ed. Orofacial Growth and Development. New York, NY: Walter De Gruyter Inc; 1977.
- Ramfjord SP et al. Increased occlusal vertical dimension in adult monkeys. J Prosthet Dent. 1981; 45(1): 74-83.
- Berry DC et al. Attrition: possible mechanisms of compensation. J Oral Rehabil. 1976; 3(3): 201-206.
- Crothers A et al. Vertical height differences in subjects with severe dental wear. Euro J Orthod. 1993; 15(6): 519-525.
- Rivera-Morales WC et al. Restoration of the vertical dimension of occlusion in the severely worn dentition. Dent Clin North Am 1992; 36: 651-664.
- Tanne K et al. Stress distributions in the TMJ during clenching in patients with vertical discrepancies of the craniofacial complex. J Orofacial Pain 1995; 9: 153-160.
- Nitzan DW. Intraarticular pressure in the functioning human temporomandibular joint and its alteration by uniform elevation of the occlusal plane. J Oral and Maxillofacial Surg 1994; 52: 671 -680.
- Ito T et al. Loading on the temporomandibular joints with five occlusal conditions. J Prosthet Dent 1986; 56:478-484.
- McNamara JA. The role of muscle and bone interaction in craniofacial growth. In: McNamara JA Jr (ed.). Control Mechanisms in Craniofacial Growth, Monograph 3, Craniofacial Growth Series. Ann Arbor, MI: University of Michigan Press, 1975.
- Enlow DH et al. Research on control of craniofacial morphogenesis: An NIDR state-of-the-art workshop. Am J Orthod 1977; 74: 509-530.
- Araki A et al. Effect of decreased vertical occlusion on mandibular condyle of senescence-accelerated mouse P8 [Abstract 706]. J Dent Res 1999; 78:194
It is well known in the dental community that a harmony between the intercuspal position of the teeth with the “home” position of the TMJ is less likely to be orthopedically unstable. This relationship is called “centric relation.” It is a very reproducible position of the mandible as it hinges against the base of the temporal bone, making treatment planning that includes changes of how teeth close against each other much more predictable.
We will talk about the clinical implications of this overview in a different segment.
(To be continued)
Intensive care for heavily decayed teeth
TheraCal LC (Bisco) – Product Report
Most dentists attempt to restore teeth while preserving as much tooth structure as possible. However, a lot of decay sometimes develops under exisiting restorations. Its removal may cause the dental pulp to be very close to the prepared tooth surface or even lead to a small pulp exposure.
A variety of treatment choices and materials have been offered to address such situation. Despite a direct or indirect exposure of the dental pulp, one should consider treatment methods that help avoid the need of a root canal treatment.
The dental-product company Bisco has released a new pulp-sealing product: TheraCal LC.
It is a radiopaque, light-curable composite that contains “apatite-stimulating” calcium silicates to protect and stimulate pulpal and dentin repair. It is considered to have better biological properties than the classical pulp-capping agents calcium hydroxide, GIC-based or RMGI materials.
TheraCal LC is a Resin Modified Calcium Silicate (RMCS) that has been reported to stimulate apatite formation and the formation of secondary dentin. It is an alakaline calcium silicate that is based on the chemistry of Mineral Trioxide Aggregate (MTA). It provides an early high alkalinity (pH 10-11) that is required for pulpal healing and which reverts back to a neutral pH after several weeks. It has a high calcium release, which is critical for the stimulation of calcium apatite formation and secondary dentin bridge formation while providing a hermetic seal of the exposed or non-exposed pulp.
To healthier teeth!
The Gingival Smile Line?
The smile is formed in two stages. In the first stage, the upper lip is elevated to the nasolabial fold by contracting the levator muscles that originate in the fold and insert in the upper lip. The lip gets raised by the medial muscle bundles at the anterior teeth and by the lateral muscle groups at the posterior teeth until it gets stopped by the cheek fat above the nasolabial fold. The second stage raises the nasolabial fold as well as described further below. The final stage of smiling is often accompanied by squinting. (Rubin et al. Anatomy of the nasolabial fold: the keystone of the smiling mechanism. Plast Reconstr Surg 1989; 83: 1-8.)
A smile is not just determined by the form and proportions of upper teeth. A smile also has a "red" element, which consists of the lips and the gums. Not everyone shows his gums when smiling. In fact, there are three categories of smiles when it comes to gum exposure, which are signified by the level of the upper lip and called low, average, and high lip line.
Among these three categories, there is a sex difference. Low lip lines are more common in males at a ratio of 2.5 to 1. High lip lines are more common in female individuals at a ratio of 2 to 1.
While some people are born with low lip lines, they are often identified with an "aging" smile, because one characteristic of aging is the progressive sagging of the face, which leads to more and more pronounced facial grooves and a sagging of the mouth relative to the position of the teeth. Hence, upper teeth become less and less visible in any given patient throughout a life time, while lower teeth become increasingly exposed during speech.
A short upper lip is considered youthful. It often coincides with a high lip line and more exposed "red" of the gingiva adjacent to the upper teeth. Hence, some exposure of gingival tissues can be considered youthful. However, if it is excessive, it becomes a gummy smile, which leads to an unattractive imbalance between red and white.
A study demonstrated that the upper lip line, relative to the gingival margin of the maxillary central incisors, is positioned 1.5 mm higher in women than in men during a maximum smile (Peck at al. Some vertical lineaments of lip position. Am J Orthod Dentofacial Orthop 1992; 101(6): 519-24.). A maximum smile is characterized by maximum upper lip and nasolabial fold elevation by the levator labii superioris, zygomaticus major, and the superior fibers of the buccinator muscle.
The same authors determined that persons with gingival smile lines (high lip lines) have significantly more efficient lip-elevation muscles. (Peck et al. The gingival smile line. The Angle Orthodontist 1992; 62(2): 91-100.) They also questioned "short" lips as a reason for a high lip line. Hence, a high lip line can be attributed to the dynamic spectrum of facial muscles rather than anatomical dimensions.
This is important to know for smile designs, because one cannot automatically assume a high lip line when observing an interlabial gap at rest position. It becomes apparent why provisionals are such an important step when creating optimum smiles. The incisal-edge position of the upper central and lateral incisors is not just determined by its distance to upper and lower lip during a smile, but also by its relative position during speech and rest position.
The exposure of gingival tissue in patients with high lip lines is not always unaesthetic. In fact, it is often considered very attractive, youthful, and playful. Just look at the smiles of some supermodels. Only severely exposed gummy smiles are considered unattractive. However, the symmetry of gingival margins becomes much more critical in individuals with high lip lines where the scalloped margins of the maxillary gingiva are all visible during a maximum smile. Hence, a cosmetic dentist might consider to correct any gingival asymmetries prior to developing new smile lines in such patients.
True Periodontal Rehabilitation - A Future Pillar of Cosmetic Dentistry
Periodontal health is a prime prerequisite for cosmetic dentistry. There is no "aesthetic" smile makeover without complete oral health. Periodontal tissues carry the work of a cosmetic dentist for an entire life time. In addition, the primary purpose of a smile design is the display of youthfulness and health. Pink and firm gums are representative of a healthy person.
A recent study has discovered for the first time a biological intervention that might reverse the signs of periodontitis. This is big news since all approaches to regenerative periodontal treatment have been very limited. Loss of alveolar bone and periodontal tissues could mostly only be halted and, in reality, never be reversed to the original health of the alveolar bone as found prior to the onset of this disease.
Dr. Hajishengallis of Penn Dental Medicine with primary investigator Dr. Maekawa published is findings in the Journal of Clinical Periodontology. He described his observations when delivering the inhibitor Cp40 of C3, the third component of the complement system. The complement system is part of the immune system. It assists the ability of antibodies and phagocytic cells to eliminate microbes and damaged cells from an organism. This causes inflammation, which is a main contributing factor for gum disease. Hence, an integral aspect of periodontitis is auto-immune activity of the human body. C3 is a vital step of the cascading events that lead to full activation of the compliment system. Dr. Hajishengallis showed that the mere application of Cp40 by local injection once a week reversed the inflammatory aspect of gum disease.
This is fantastic news since cosmetic dentistry without a complete rehabilitation of diseased periodontal tissue would be severely compromised, despite the application of state-of-the-art techniques, such as alveolar ridge augmentation procedures, connective tissue grafts, and the placement of dental implants.
References:
Maekawa T et al. Genetic and intervention studies implicating complement C3 as a major target for the treatment of periodontitis. J Immunol. 2014 Jun 15; 192(12): 6020-7.