Your Best Smile

The Bellevue Center for Cosmetic Dentistry

The Art of Matching Select Porcelain Restorations to Anterior Teeth in Bellevue,WA

November 9th, 2007

Introduction

Matching a single central incisor is challenging but possible if the dentist and ceramist understand the principles of natural oral esthetics; good tissue health and perfectly reflected tooth contours at the midline are just as important as the actual color of the teeth. If the teeth are rotated or the roots are misaligned, the match can become far more challenging because the ideal contours of the porcelain must, by necessity, be transitioned into the poorly aligned contours of the malpositioned tooth. Some of our color-matching illusions stem not just from matching a color, but also from where that color reflects light. Just by changing the position, of a tooth it is possible to alter the
appearance of a color. Sometimes it is necessary to alter the color of a tooth to match its position, in order to change how that color is perceived by the eye and then interpreted by the brain.

Just by changing the position of a tooth it is possible to alter the appearance of a color.

Ocular Perception and Brain Interpretation

Most experienced cosmetic dentists are familiar with the basic three dimensions of color: Hue, value, and chroma (saturation). In addition to the three dimensions of color, there are other factors that must be managed for a successful shade-matching experience. One significant factor is the color property of metamerism (in which either of two colors of different spectral composition appear identical to the eye of a single observer under some lighting conditions but different under others; or that, under constant lighting conditions, they appear identical to some observers and different to others).1,2 Metamerism occurs when two objects are the same color but are molecularly different in structure. As with two different fabrics, for example, wool and silk, dyed with exactly the same dye—the two colors may match in natural daylight, but may not match in a different type of light (e.g., incandescent).

figure1.jpg

Figure 1: Your mind is probably telling you that the green dot in the middle of the board is brighter than the green dot at the top of the board. Is it really? (Hint: Your brain will interpret a color based upon its surroundings.)

Interpreting Color Based on Context

Other factors that influence color are the effects perceived by the eye and interpreted by the brain. One example is the way that the brain interprets a color based on its context. In Figure 1, the light gray square in the shadow cast by the cylinder is exactly the same color as the dark gray square in direct light, but our mind probably refuses to “believe� it.3 This is because we have learned to interpret colors based upon their context. A color that is perceived to be in the shade will appear to be much brighter than the exact same color if it appears to be in direct light. Because of this perception, brighter teeth will generally appear to be larger and closer.4,5 Conversely, a prominent tooth that is the same shade as its neighbors that are in the shadows will appear to be darker.

Metamerism occurs when two objects are the same color but are molecularly different in structure.

This fact is significant when matching the central incisors, especially if they happen to be prominent. In Figure 2, the two central incisors appear to be lower in value than the lateral incisors. When the lateral incisor is digitally cut and pasted directly onto the adjacent central incisor, teeth #9 and #10 appear to be the same color (Fig 3). The reason for this discrepancy is that our eyes interpret the central incisors as being prominently placed in the light, and the surrounding teeth as being more lingually placed back in the shadows. The brain then interprets the central incisors as being lower in value based upon their context, just as in the example of the gray shadow in Figure 1.

figure2.jpg

Figure 2: The new all-porcelain restorations are an improvement over the porcelain-fused-to-metal crowns. The hard and soft tissue contours, margins, and translucency look healthy and realistic.

figure3.jpg

Figure 3: When the left lateral is digitally positioned over the central incisor, the value of the two teeth appears to be the same. This is similar to Figure 1, in which the color of the green dot is affected by its context. The color of these teeth is being influenced by context, not by value of the porcelain. We expect the more prominent central incisors to appear lighter than the lateral incisors.

figure4.jpg

Figure 4: The color of the porcelain on these central incisors is actually lighter than the adjacent lateral incisors. In spite of this fact, the restorations appear to match because of the inherent expectation that these two teeth will appear slightly lighter than the lateral incisors.

The porcelain restorations on the two centrals shown in Figure 4 appear to match better than the previous set of veneers. In this case, the central incisors are slightly lighter than the adjacent teeth. To achieve the greatest colormatching accuracy with photographic color communication, it is important to place the shade tab in the same plane as the tooth being matched. In my experience, the most ideal shade tab position for color matching is sitting adjacent to and in the same plane as the tooth being matched (just like a bridge pontic). This ideal shade tab position also can be recreated using image manipulation software. This can be done by photographing the shade tab placed in a position incisal-edge-to-incisal-edge in the ex-act same plane with the tooth that is being matched. The photograph of the shade tab can then be digitally manipulated to place that shade tab into the “pontic� position adjacent to the tooth being matched for more precise color comparison (Fig 5). This enables the laboratory to visualize the subtle differences between the shade tab and the actual tooth, and to modify the color of the porcelain accordingly.

figure5.jpg

Figure 5: Trial shade tabs photographed and manipulated with software to position the shade tabs in the same plane and position as the adjacent tooth.

Successfully matching central incisors involves more than simply choosing the correct hue, value, and chroma.

Conclusion

Successfully matching central incisors involves more than simply choosing the correct hue, value, and chroma in order to match a porcelain restoration to a natural tooth. It requires an understanding of other factors, such as tooth contours and tissue health. It also requires an understanding
of other dimensions of color such as metamerism, visual context, and lighting. Understanding and managing these properties of color, lighting, and perception can help to increase the success of color-selecting appointments and assist with identifying and trouble shooting particularly challenging shade-matching situations.

References

    1. MedlinePlus. Merriam-Webster Medical Dictionary.
    Definition of metamerism. Accessed
    August 23, 2007, at http://www2.
    merriam-webster.com

    2. Magne P, Belser U. Bonded Porcelain Restorations
    in the Anterior Dentition: A Biomimetic
    Approach (p. 230). Hanover Park, IL: Quintessence
    Pub.; 2002.

    3. Adelson E. Checkershadow illusion. Accessed
    August 22, 2007, at http://web.mit.edu/
    persci/people/adelson/checkershadow_illusion.
    html

    4. Magne and Belser, op cit., p. 84.

    5. Chiche G, Pinault A. Esthetics of Anterior
    Fixed Prosthodontics (p. 31). Hanover Park,
    IL: Quintessence Pub.; 1994.

Reprinted by Permission, The Journal of Cosmetic Dentistry Fall 2007, Volume 23, Number 3.

Bellevue Dentist Supports Domestic Violence Awarness Program through Give Back A Smile

October 31st, 2007

October 4, 2007 Bellevue, Washington – Help heal the effects of domestic violence by participating in the whitening program hosted by local dentist Dr. Lynn Jones. During Domestic Violence Awareness Month Dr. Lynn Jones will perform whitening treatments for a direct donation to Give Back A Smile (GBAS), a program designed to help survivors of domestic violence.

Radio Interview with Dr. Jones

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The American Academy of Cosmetic Dentistry (AACD) Charitable Foundation’s primary program, GBAS, provides cosmetic dental care to survivors of domestic violence who have suffered damage to, or lost, their smiles at the hands of someone they loved. With the support of Discus Dental and Ultradent Products, Inc. AACD member volunteers provide whitening treatments to patients in support of GBAS.

“The GBAS whitening program is a collaborative way for dentists and patients to make a difference in the lives of survivors of domestic violence. It is a win, win, win situation for everyone involved,” commented Dr. Jones.

How the GBAS Whitening Program Works

  • Discus Dental and Ultradent Products, Inc. donate whitening kits to participating AACD member volunteers.
  • Patients who undergo whitening treatments as part of the program make their payment directly to GBAS.
  • Contact Dr Lynn Jones’s office at (425) 688-1345 to ask how you can participate in the whitening program.
  • About Give Back A Smile
    The GBAS program was launched May 27, 1999. Since then, more than 6,000 AACD volunteer dentists, dental laboratories and other dental professionals have volunteered their time and expertise pro bono for the GBAS program. Since its inception, over 550 domestic abuse cases have been completed for a total dollar value of over $4.3 million. Currently, 300 applicants are being treated throughout the United States.
    Domestic violence survivors who have suffered dental injuries from abuse from a former intimate partner or spouse can learn more about GBAS online at: www.givebackasmile.com or contact GBAS toll-free at: 800.773.GBAS (4227) . Survivors must make an appointment with a counselor, domestic violence advocate, social worker or therapist to complete the advocate section of the GBAS application. GBAS conducts the initial review of the application however the dentist has the final say as to the eligibility of the applicant. If eligible, the AACD connects the survivor with a local GBAS volunteer who provides treatment at no charge to the recipient. Donations for the GBAS program can be made to the AACD Charitable Foundation, 5401 World Dairy Drive, Madison, WI 53718-3900.

    Dr. Lynn Jones is a GBAS volunteer and whitening program provider in the Washington area.

    Since its founding in 1984, the American Academy of Cosmetic Dentistry (AACD) has been dedicated to advancing excellence in the art and science of cosmetic dentistry and encouraging the highest standards of ethical conduct and responsible patient care among cosmetic dentists. The AACD and its more than 7,600 members focus on creating beautiful smiles through services like teeth whitening, lifelike porcelain veneers, and natural-colored restorations, as well as providing trends, statistics and information to the public. The AACD Charitable Foundation’s primary program, Give Back A Smile is dedicated to providing cosmetic dental care at no cost to survivors of domestic violence. Give Back A Smile raises awareness of domestic violence and gives survivors of domestic violence hope for a better tomorrow truly something to smile about.

    Local Bellevue Dentist goes to the Emmy’s to whiten celebrities teeth for charity

    October 5th, 2007

    This year, the official Emmy pre-party put on for the enjoyment for celebrities was held on the Penthouse Floor of the Beverly Hills Wilshire Hotel made famous from the movie Pretty Woman. The Awards Show Pre-Party has become almost as famous as the ceremony itself, held every year at a different location, celebrities come in their day clothes and they come prepared to be pampered by some of the Worlds Wealthiest companies. This year only Less than 20 companies were invited to attend, including General Motors, Perry Ellis, Heineken, Joico, Dove; and each corporate sponsor comes ready to gift the celebrities with more than a thousand dollars worth of product and services each.

    But this year, also invited to be a sponsor was local Bellevue dentist Lynn Jones on behalf of her eastside dental practice as well as representing the national non-profit organization Give Back a Smile which is made possible by the American Academy of Cosmetic Dentistry to which Lynn is the 2007-2008 Chair of the Board of Trustees. In an effort to bring more attention to Give Back a Smile which has been seen on Oprah, CNN, and Dateline; our city’s very own Dr. Lynn Jones teamed up with the famous TV personality dentist Bill Dorfman from ABC’s Extreme Makeover. In the make shift dental operatory which looked like something more from a scene in I LOVE LUCY; waiters and waitresses carrying bottles of Heineken and designer entrées silently catered to the celebrities who sat back in the dentist chair, and had a pretty hysterical time with Dr. Lynn Jones and Dr. Dorfman. As the primary program for the AACDCF, Give Back a Smile shines through as the pride and joy of the AACD’s philanthropic efforts. Since the inception of GBAS more than 500 survivors have moved from devastation to rejuvenation with the aid of AACD dentists. This year the AACDCF volunteer dentists with the support of the labs completed 112 cases in 33 states totaling 1,072878.00! With national coverage, support from the AACD and generosity of volunteer members, GBAS is sure to continue on this wonder path of restoring the smiles and lives of domestic violence victims by restoring their smiles. All of the celebrities who had dental models made for their whitening appliances agreed to allow GBAS to auction of their models to support the organization at its annual fundraiser in New Orleans this year.

    Dr. Lynn Jones first felt her calling to become a dentist in 1968, the year she graduated from high school, and coincidentally in a time when the guidance counselors at her high school (as well as the men of the dental industry) advised her that women did not go to dental school, because it was a career too demanding for women who needed time to raise children. Instead she was advised to become a dental hygienist. When she graduated from the University of Washington hygiene school in 1972 with a BS degree in dental hygiene, to her disappointment the equal rights amendment for women had not passed, however something significant for women did Title IX. Title IX basically said that if a school program accepts federal money, it must give equal opportunities to women. Out of the 100 students that were accepted that year, only 18 were women, including Lynn Jones. At a time when the school had not yet made proper adjustments; they shared a locker room with the male classmates, the female restroom was in the patient waiting area, many instructors refused to speak to them, as well as male students who constantly told them they did not belong there. As a result the women in Lynn’s class banded together and became very close. They all felt a great responsibility to future woman students to do well for fear that privilege would be taken away from them. Amazingly, all of the women graduated in the top half of their class. Since then, Lynn formed the summit AACD affiliate chapter of cosmetic dentistry where they combine high-quality lectures with hands-on experience and patient treatment for comprehensive care. She also teaches microscope hands-on courses for dental meetings and for the Newport Coast Oral Facial Institute.

    Today, Dr. Jones’ patients are given a red carpet treatment of their own, at her practice located in Downtown Bellevue in the Hyatt Building of the Bellevue Collection. “The amenities at our dentist are great, but its her kind heart that have kept us loving her all these years. She really is living proof that if you want to believe in something, all you need to do is believe in yourself first. Hey not to mention Dr Jones and I love chatting about Yoga together!” patient Mary Bridgeforth says with a laugh. “She’s so cool ya know.”

    For Press Inquiries, Please Contact Lori Pacchiano (206) 856-8369

    Ultreo Ultrasonic Tooth Brush

    July 25th, 2007

    The new Ultreo ultrasonic toothbrush takes power brushing where it’s never gone before. Invented at the University of Washington in association with former scientists, engineers and executives of Optiva Corporation (developers of the Sonicare toothbrush), Ultreo is the first power toothbrush to combine ultrasound waveguide technology with precisely tuned sonic bristle action. Ultreo’s bristles create microbubbles that are powerfully activated by nearly 4 million cycles of ultrasound energy per brushing channeled by a proprietary ultrasound waveguide.

    ultreo tooth brush

    Recent studies have shown the Ultreo toothbrush to remove 95% of plaque from hard-to-reach areas during the first minute of brushing. The Ultreo’s use of ultrasonic waves also signigicantly removes biofilms on the teath and mouth without bristle contact. Biofilms are the leading causes of harden plaque, tooth decay and bad breath. People who have begun using the Ultreo have noticed a sharp decrease in gingivitis in less than 30 days and an overal decrease of gum bleeding. The Ultreo has also been found to reduce extrinsic stains on the teeth after 2 to 4 weeks of use.

    The Bellevue Center for Cosmetic Dentistry is proud to be one of the first dental practices to be an authorized dealer for this incredible tooth brush. Please contact us today to purchase yours. The Ultreo toothbrush is not available in stores. (425) 688-1345

    Seattle Dental Cosmetic Composite Techniques

    June 10th, 2007

    With the new generation of composites, it’s possible to build beautiful veneers and restorations that blend invisibly with the natural teeth. Composites allow for the maximum artistic expression on the part of the dentist and are a perfect way to develop excellent color matching and smile design. A well-designed composite veneer can rival its porcelain counterpart in esthetics and longevity. Patients often prefer composites because tooth reduction can be minimized for a composite restoration. Composites are fast; patients love the same day service, and when used in the right place composites can be quite durable.

    There are many factors used to provide the proper restoration of teeth with dental composites. They include the following:

    Smile Design
    Tooth Color
    Tooth Shape
    Position of Teeth
    Esthetics
    Composite Selection
    Tooth Preparation
    Bonding Techniques
    Composite Placement Techniques
    Composite Sculpture
    Composite Polishing

    In this dental video tutorial, Dr. Lynn A. Jones, of the Bellevue Center for Cosmetic Dentistry, performs a composite dental repair of the upper left front tooth. She takes into account tooth preparation, tooth contouring, color and texture through this hands-on experience. Dr. Lynn A. Jones is an expert in the use of microscope dentistry and is only woman dentist accredited by the American Academy of Cosmetic Dentistry in the state of Washington.

    Quicktime 7.0 or greater required. Get Quicktime. It’s FREE!

    Call Dr. Lynn A. Jones, One of Seattle’s Best Cosmetic Dentist , today for a consultation. (425) 688-1345

    Beautify your Smile with a Gum Lift by Bellevue Cosmetic Dentist Lynn A. Jones DDS

    May 12th, 2007

    Being too embarrassed to smile is often the case with many patients that come to the Bellevue Center for Cosmetic Dentistry. Often times a persons smile exposes too much of their gums making them self conscious of their appearance. Dr. Lynn A. Jones is a pioneer in the process of advanced gum lift dentistry and is a nationally recognized leader and teacher in this procedure. This video show her attention to detail, precision and expertise in this technique.

    Warning this surgical dental video shows graphic visuals of a gum lift dental procedure

    Quicktime 7.0 or greater required. Get Quicktime. It’s FREE!

    Call Dr. Lynn A. Jones, Bellevue top Cosmetic Dentist , today for a consultation. (425) 688-1345

    Ask Bellevue Cosmetic Dentist, Dr. Lynn a. Jones

    May 8th, 2007

    Many patients come to the Bellevue Center for Cosmetic Dentistry and ask a very basic question. Is there is a way to hide or cover up the old style metal fillings currently in my mouth now? Dr. Jones answers this question in this video.

    Quicktime 7.0 or greater required. Get Quicktime. It’s FREE!

    Seattle Dentist Neuromuscular Smile Training

    April 11th, 2007

    As with any complex neuromuscular activity the smile can be trained in efficient performance and correct musculoskeletal activation. It has been well established that training exercises involving repetitive activity with visual feedback lead to improved function. These techniques have been applied to sports acting, dance, etc. and can also be applied to smiling.

    Perform the following smile exercises in front of a mirror:

    1. Move the corners of the mouth up slightly without revealing any teeth. Hold this position for ten seconds while you see and feel how the muscles move.

    2. Move to a half smile. The upper corners of the mouth move slightly more upward, the lips spread, and the cheeks move somewhat. Hold this position for ten seconds, again seeing and feeling the movement of the muscles.

    3. Advance to a full smile. The corners of the mouth move into the uppermost position, the lips are stretched taut, and the teeth become exposed. The amount of exposed dentition that constitutes a pleasing smile is determined by your personal taste and preference. Repeat in reverse sequence

    4. To strengthen the smile muscles repeat these exercises using resistance. To accomplish this place two index fingers into the corner of the mouth and use them to resist the movement of the smile muscles. Each position should be held for ten seconds and repeated ten times a day.

    For most people it is fairly easy to achieve the half smile because this is the extent of their typical smile, since minimal teeth have been bared. The importance rests in separating each of the muscle movements, giving an awareness of muscle movement as opposed to simply unconscious behavior.

    A self curing silicon can be injected into the nasal spine to hold down the lip in a gummy smile.

    Seattle Dentist Deprogrammer FAQ’s

    February 7th, 2007

    What is a dental deprogrammer?

    A deprogrammer is a removable dental appliance, similar to an orthodontic retainer that is worn over the teeth to prevent them from biting together. It is designed to diagnose the cause of problems related to the bite. It is also occasionally used to treat some bite related problems. If you are planning to restore key teeth or if you are having bite and jaw related symptoms your dentist may recommend a deprogrammer for you.

    How do I know if I have bite problems?

    Some of the most common signs of bite related problems are:

  • Worn teeth
  • Cracked and fractured teeth
  • Sensitive teeth
  • Pain or cramping in the jaw muscles
  • Pain in the jaw joint
  • Popping or locking of the jaws
  • Head aches
  • Loose teeth
  • Notching in the tooth at the gum line
  • Clenching or grinding the teeth
  • No home position for the teeth
  • Earaches or ringing
  • These problems may be caused by teeth that do not fit together properly or by habits such as clenching and grinding.

    How does the deprogrammer work?

    The way this works is the deprogrammer creates a little platform between the front teeth that prevents the back teeth from biting together. This frees up the muscles and jaw joint to relax into their physiologically ideal resting position without any influence from maximum intercuspation.

    The deprogrammer is both a diagnostic tool and a way to temporarily relax the jaw and reduce muscle tension, headaches and excess wear on the teeth.

    How should I use the deprogrammer?

    Wear the deprogrammer as much as possible and always remove it to eat or to clean the teeth. It is especially important to wear it all night prior to and the day of your scheduled evaluation. Keep the deprogrammer in until you are asked to remove it.

    Please bring your deprogrammer to every appointment.

    How long does it take to deprogram the teeth?

    Some people can deprogram in a few minutes and some take weeks or even months.

    How do you know when the teeth are deprogrammed?

    The jaw muscles will feel comfortable and relaxed and the teeth will touch on the discluding element in exactly the same place every time. It is also important to determine that this contact point is not changing over time.

    How can bite problems be fixed?

    Once the cause of the bite problem has been determined and the most stable position for the jaw has been determined, you have several treatment options.

    1. Bite appliance: You may get a night guard from your dentist or your deprogrammer can be made into a long-term appliance to use during episodes of headache and clenching

    2. Orthodontics: Sometimes the teeth may be moved with braces so that the tooth, jaw and chewing positions are in harmony.

    3. Selective filing: Sometimes the bite can be corrected by selectively filing points on the teeth that keep the jaws from functioning properly

    4. Restoring the teeth: The bite related problems may also be corrected by restoring the teeth with porcelain, gold or fillings.

    Trouble shooting

    Pain in the jaw joint: Remove the deprogrammer immediately and consult with your dentist for an evaluation.

    Headaches from the deprogrammer: Remove the deprogrammer and consult with your dentist immediately. The deprogrammer may need to be adjusted.

    Lower front teeth are getting loose: Remove your deprogrammer and consult your dentist immediately. The deprogrammer may need to be adjusted.

    Teeth are getting sensitive: Remove your deprogrammer and consult your dentist immediately. The deprogrammer may need to be adjusted.

    Sore spots on the gums: Consult with your dentist. The deprogrammer may need to be adjusted.

    The bite changes after wearing the deprogrammer for a while. This is normal and means that the deprogrammer is working. The sensation should go away shortly after the deprogrammer has been removed from the mouth.

    After considering your goals and specific condition the dentist will recommend one or a combination of these treatments to improve the health of your teeth and jaws.

    Our goal is to provide the highest level of comfort and esthetics. Our mission is to create smiles that look beautiful and feel wonderful. Please feel free to contact us with any questions you might have.

    Dr. Lynn A Jones
    Bellevue Center for Cosmetic Dentistry Dr. Lynn Jones DDS
    10500 NE 8th, #208
    Bellevue WA 98004
    Phone 425-688-1345

    Bellevue Evidence Based Treatment Planning: Managing Occlusal Problems – Part 2

    February 4th, 2007

    Last Month I asked you to consider how you look at occlusal problems. Hopefully this created room for some new ways seeing and thinking about some of the conditions presented by your patients. This month I am going to suggest a different approach to evaluating occlusal problems that may simplify the diagnostic process and help direct treatment in a more logical and more importantly a predictable fashion. Most of this information is based on the teachings of John Kois, Functional Occlusion I & II: Science Driven Management (Courses II & VII)

    What is disease?

    Before I define health I would like to propose a way to define disease. Webster’s first definition for disease is uneasiness distress . This is followed with any departure from health; illness in general. It goes on to say a particular destructive process in the body, with a specific cause and characteristic symptoms; specific illness; ailment; malady. We can generally place dental disease into one of four risk categories:

  • Periodontal: inflammation, bone loss, mobility and eventual tooth loss
  • Biomechanical: Decay, abscess, large restorations, break down and eventual tooth loss
  • Functional: Bruxism, occlusal dysfunction, constricted envelope of function, bite collapse, temporo-mandibular dysfunction (TMD)
  • Aesthetic: High lip line, sensitive to appearance, damaged discolored or otherwise non-esthetic teeth.
  • In each of these risk categories there are a host of symptoms including pain, anxiety, sleep loss, inability to chew, bleeding gums and many more. These symptoms are helpful in making a diagnosis but thinking of dental disease in these four categories is a useful method for evaluating the significance of the patients concerns as they relate to disease.

    The occlusion may contribute to all areas of dental disease causing restored teeth to fracture and periodontal pockets to worsen. Occlusal dysfunction also causes a common esthetic concern, short and badly worn anterior teeth. Diagnosing how occlusal dysfunction is causing damage to the oral cavity is key to properly treating the problem.

    Diagnosing Occlusal Dysfunction

    Many theories on occlusion are based in locating centric relation which has had many definitions over the years. Earlier definitions defined centric relation as the most retruded position of the condyle. Recently it has been defined as the most superior position of the condyle1 and even more recently the most superior anterior position of the condyle2.

    Centric relation is currently defined as “the maxillomandibular relationship in which the condyles articulate with the thinnest avascular portion of their respective disks with the complex in the anterior-superior position against the shapes of the articular eminences. This position is independent of tooth contact. This position is clinically discernible when the mandible is directed superiorly and anteriorly. It is restricted to a purely rotary movement about transverse horizontal axis. “3

    centric occlusion dentistry image

    Fig 1 a and b Centric Occlusion: The occlusion of opposing teeth when the mandible is in centric relation. (CR is indicated by the alignment of the pink marks) This may or may not coincide with the maximal intercuspation

    Centric relation is not a disease, nor is it a diagnosis. It is only a stable position that we can use as a point of reference when we are making a diagnosis. We can change the bite with orthodontics and prosthetics or surgery in more extreme cases. We know that muscles can change their size and shape, Think of body builders and ballerinas. It is more difficult to change the position of the condyle.

    For instance when the bite has been locked in behind the front teeth as in a class II occlusion with a deep overbite I have frequently observed popping TMJ and reports of headache. It appears as though the guide path pushed the condylae distal to CR In fact roughly a third of my TMD patients fall into this category. Dr. Kois has referred to this case type as a Constricted Chewing pattern. Typically they will get tired muscles and they will exhibit more wear on the anterior teeth and often practically no wear on the posterior teeth unless they are very advanced in the degree of wear. When attempting to locate CR the initial point of contact will usually appear on an anterior tooth. If CR is located with the TMJ and related muscles completely deprogrammed the initial point of contact does appear on the anterior teeth. Some other keys to identify a constricted envelope of function is mobility on the anterior teeth, spaces between the anterior teeth and a lack of mobility on the posterior teeth.

    seattle cosmetic dentistry maximal intercuspal image

    Figure 2 a and b Maximal Intercuspal Position (MIP): The complete intercuspation of the opposing teeth independent of condylar position, sometimes referred to as the best fit of the teeth regardless of the condylar position. Also called maximal intercuspation or MI

    The next level of occlusal dysfunction is the more familiar posterior interference into MIP creating avoidance patterns. These patients can be difficult to manipulate because the muscles will tighten up when any attempt is made to put them into CR. If you deprogram their TMJ and muscles of mastication they will typically have a posterior IPC. These cases can take longer to deprogram and be more difficult to treat. The bite needs to be repeatable on the deprogrammer to determine that the muscles have fully deprogrammed. If the bite wanders around on the discluding element the bite has not fully deprogrammed and the patient needs to wear it longer. .

    seattle cosmetic dentistry tss deprogramming appliance image

    Figure 3 a and b The NTI – tss Deprogramming appliance. The NTI is an effective deprogrammer but it is very bulky for daytime wear. This smaller diameter appliance might present a choking risk and should fit tightly onto the teeth.

    Bruxism can sometimes be caused by interferences and problems with the occlusion. When it is, the bruxism can be corrected by correcting the occlusion. Other times the bruxism is independent from the occlusion and the cause may be unknown. It may be a sleep disorder or some other non-dental cause. These so far unstoppable bruxers can be identified by the horizontal grooves they grind into their deprogrammer. When you see these marks on a deprogrammer, you have strong evidence that nothing can be done dentally to stop this destructive habit. The best you can do is protect the teeth from the destructive forces of grinding by covering the teeth with some kind of bite appliance. The patient needs to be advised that he / she is likely to break and damage more teeth and porcelain in the future even if they do wear a night guard.

    seattle cosmetic dentistry kois deprogrammer image

    Figure 4 The Kois deprogrammer is a Hawley bite plane with a discluding element that contacts the lower incisors on one point.

    Identifying the key elements of a healthy functional occlusion

    For the patients who have constricted chewing patterns or posterior interferences there situation can be improved by equilibrating, orthodontically moving or prosthetically rebuilding the bite into proper function.

    The anterior teeth must allow room for the mandible to move through its normal envelope of function without any constriction of the chewing pattern. If there is no bruxism, the jaw will be more comfortable with canine guidance to help it find maximum intercuspation. There needs to be bilateral simultaneous contact of at least the four corners, the canines and molars. All movements should be harmonious with the function of the TMJ as determined by a deprogramming appliance.

    Conclusion

    Many of the things being taught about the TMJ are partially correct. This leads to confusion and frustration with diagnosis and treatment. Because we don’t have all the answers there is a constant controversy about the right way to treat TMD and occlusal problems. It would be helpful if we could combine all of the information that is available on this topic and discover the best solutions for our patients. The human body is very complex, and there are so many factors involved when we are treating disease. Trying to come up with a one size fits all plan will limit our ability to provide the best treatment for every patient. I hope that this article provoked new questions and opened the door for a new way of looking at your cases. This is an invitation to examine the problems associated with treating occlusal dysfunction and to look at them from a different perspective hopefully resulting in new and better ways of treating occlusal problems.
    Lynn A. Jones, DDS, RDH

    Dr. Jones is a Graduate of the University of Washington, School of Dentistry and maintains a fulltime cosmetic dentistry practice in Bellevue and Seattle WA

    1. Evaluation, Diagnosis and Treatment of Occlusal Problems, Second Edition 1989; Dawson, PE
    2. Management of Temporomandibular Disorders and Occlusion 4rth Edition, 1998; Okeson, JP
    3. The Glossary of prosthodontic terms 7th edition



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