Dentures: Then and Now
Over 18 million Americans are missing all their natural teeth. Another staggering 44 million Americans are missing quadrants of molars and bicuspids. Denture wearers face a number of compromises, however; the advances in dentistry allow better solutions. In this segment, subjects involving dentures and improved treatment options will be discussed and wonderfully illustrated.
- Everything you ever wanted to know about Dentures
- Overdentures supported by natural teeth abutments
- Overdentures supported by implants
- Overdenture Abutments: Bar and Ball Designs
- The Science of Proper-Fitting Dentures
- What is Tissue Conditioning and Softliners
- How to clean your Dentures
The Evolution of Dentures
There has been an evolution in denture technology in the past 200 years. The following pictorial will show how far we have come.
Revolutionary Dentures
This was state of the art in 1790. People need teeth. Teeth represent us in how we smile, speak, and socially share meals. Teeth are the initial stage of digestion. To eat a proper diet, teeth need to function. The above set of dentures reflects the brave journey to replace what is missing.
Today’s dentures are made from polished acrylic and use beautiful porcelain or acrylic teeth. Due to the public’s demand for more sensible tooth replacement, research has made it possible for improved designs and better retention.
Modern Dentures
Overdentures Supported by Natural Teeth Abutments
Overdentures is a term that describes a full denture that is anchored in some way to the bone ridge. Natural tooth roots, when fitted with attachments, can act as anchors. The important issue is bone. Bone, covered by soft tissue, is the foundation for which the denture rests on. Following initial extractions, the bone surrounding the extracted teeth resorb or shrink about 25%. That is a big change. The bone ridge continues to shrink about .5 mm in width and heigth, every year. This results in an ill-fitting denture.
When there is a root or implant in the bone, the bone gets the signal to grow around it. By tensile and compressive forces delivered to the bone and resulting bone growth, the denture wearer is able to retain supporting bone. This bone level is referred to as vertical dimension, more commonly, the space between your nose and chin. Viewing the mouth without a denture in place, can illustrate closed vertical dimension or lack of facial bone support.
This is an upper arch restored using gold copings with o-rings on the roots of the canines and first molars.
This is a lower arch restored with gold copings and dalboa attachments. Note the increase of bone surrounding the abutment root structures.
This picture shows the actual denture of the above patient which is without a palate and has metal reinforcement to prevent fracture.
This lower arch was restored by saving the canine roots and placing 2 zaag attachments. Canine roots make good abutments due to long, tapering root structure.
This bar is supported by 2 upper canine teeth.
This patient was restored with 2 different types of attachments using all of the 4 remaining canines.
This patient was restored using the same attachment design in all teeth. Notice the difference in the upper bone ridge from the less amount of bone in the lower arch.
Overdentures Supported By Implants
This cut-away view illustrates the mechanics of an implant supported overdenture.
By use of the miracle of modern implantology dentures can be non-removable or clipped on the jaw via a series of implants to increase the chewing power of the patient up to 300%.
There are a variety of ways in which a patient’s comfort, chewing efficiency, and lifestyle can be changed by fastening or anchoring the teeth to the jawbone.
Benefits of Overdentures:
• prevent bone loss
• maintain facial esthetics
• eliminate soft tissue abrasions
• improve chewing efficiency
• improve prosthesis stability and retention or eliminate prosthesis movement
• improve speech compared with full dentures
• create reproducible centric relation occlusion
• reduce or eliminate denture size and flanges
• remove easily at night to control nocturnal parafunction
• require fewer implants, which reduces overall cost.
Misch, Carl E. Contemporary Implant Dentistry.2nd Edition.
The Subperiosteal Implant Supported Overdenture
The Subperiosteal Implant framework structure sits on top of the bone instead of inside the bone and is usually limited to the lower arch. It can be the ultimate overdenture system for the lower arch especially for people with very compromised bone levels. It’s amazing the difference it makes in their lives.
The above photos demonstrate different types of lower arch subperiosteal implant designs.
For more information on Dental Implants click on the Implant section of this website.
Overdenture Attachments: Bar and Ball type Designs
This diagram from Dolder’s book on overdentures illustrates how a bar between two teeth or implants can prevent movement in 6 different directions.
This diagram alone sums up many of the benefits of a bar retained denture.
Dentures have been supported by bars between tooth roots or implants for a long time. Bars support dentures better than individual tooth roots or individual implants. There are many kinds of attachments and types of bars available.
In the 1940’s and 1950’s, a Swiss doctor named Eugene Dolder who worked out of the University of Zurich wrote many of the definitive articles about the benfits of bar-retained dentures. All of his bars were made on top of tooth roots. A typical example of his type of reconstructions is shown below.
Photograph illustrates preserved bone even in presence of diseased teeth.
Natural root structures support gold dolder bar and lower gold clip.
Upper denture which clips into upper dolder bar.
Photos taken from Dolder/Durrer The Bar-Joint Denture: A Practical Study
Dental Implants are more often used because implants are more bacterial resistant than natural teeth and roots. The amount of implants used to support a bar depends on available bone and also how much financial resource a person is willing to use. Not always, but usually, the more implants, the more retentive the bar. It is always better to over-engineer areas of compromise. Bars on the upper arch always require more implants than bars on the lower arch due to less dense bone in the maxilla and stress distribution over the system. When properly maintained, an implant supported bar system can last over 20 years.
These illustrations depict how the denture can clip onto the bar and pivot about the bar.
How hard a person bites down can be measured in pounds per square inch (psi). People who are restored with a bar and overdenture, can bite significantly harder and thus reduce food particles (bolus) more effectively. When the transfer of force is evenly distributed, there is less impingement (pinching) of the soft gum tissue.
This is a lower implant supported bar using o-rings and a clip.
This is another example of lower implant supported bar design.
The following photos depict restored with a vertical milled bar and a special milled over bar which is set inside her upper denture.
This bar is tripoded on top of 3 implants and 3 zaag attachments.
Note how important the relationship of an experienced lab technician is to the restoring doctor. An available in-house lab service is very valuable to satisfying the patient’s expectations.
This is an example of ball type designs that utilize the same concept discussed on natural tooth abutments. More examples above under Over dentures supported by natural teeth.
The Science of Proper Fitting Dentures
The best way to ensure a continued proper fit, is to be evaluated when dentures break or pivot too much. Because the bone ridge is in constant change due to re-absorption or shrinkage, more predictable options like over dentures should be discussed.
The process for making a new dentures begins with impressions.
The doctor may use your existing denture to make a custom impression taking extra measures to get information in the vestibule and any extension areas necessary. At the next appointment, a bite or jaw relation is taken which measures the relationship of the upper arch to the lower arch. Space is allowed for speech and the rest position of the mouth. From this information, the lab technician and the doctor fabricate a base in wax and set the choice of teeth in the base for the patient to view and check the fit. Upon approval, the denture is then processed and acrylic replaces the wax base. The patient can now be scheduled for the delivery of the denture. Any adjustments are down at this appointment.
To ensure the denture is esthetically pleasing to the patient, the doctor uses suggestions from the patient as well as selecting compatible teeth based on facial characteristics. The selection of denture teeth is also reliant on shape of the face, whether the patient is male or female, age, and skin color sense the gum tissue varies in different ethnic groups. Custom shading and characterizing dentures is a detail that our patients appreciate. In other words, if you want to retain the gap in between two teeth, the doctor can do so. Some of our patients have asked for gold outlines on teeth. Unique requests are accomplished with our in-house lab, state of the art equipment and some of the best lab technicians in the field. View our Before and After Gallery to see for yourself.
What is Tissue Conditioning and Softliners?
A tissue conditioner is a liner of soft pliable material which may be used to aid in the healing of sore spots in the mouth. When dentures become ill-fitting and rub or press unevenly on soft tissue, a sore spot can develop which can be very uncomfortable and even make it too painful to wear the denture at all. Soft liners allow a cushion between the denture and the gum tissue to aid in healing. A tissue conditioner is also prescribed a week or so before a patient is to have an acrylic laboratory reline (hard reline). This allows the tender gum tissue to get used to a proper fitting denture, which usually reduces sore areas from occurring after delivery of the hard reline.
How to properly clean your Dentures and Softliners?
Full and Partial Dentures should be cleaned daily to keep them in presentable and odor-free condition. Dentures can be brushed with a denture brush over a sink with water or towel to prevent breaks should the denture be dropped. The best cleaning solution is one teaspoon Clorox and two teaspoons Calgon in a half glass of water or in a plastic container, soaked overnight. During the day, the dentures should be brushed after each meal with a soft toothbrush and ordinary face soap. All tissues should be brushed as well as the tongue. Plaque can form on dentures just as it does on natural teeth. After meals, if brushing cannot be done, the dentures should be rinsed in water. Periodic soreness of the mouth can be alleviated by removing the dentures from the mouth for short periods of time. Finger massage of the sore areas is sometimes helpful. Rinsing the mouth with warm salt water (one teaspoon to a glass of water) three times daily is also helpful. Also inform your dentist of any sore that is not healing. If you wear a denture, you need to have your mouth evaluated at least once per year by your dentist. Softliners: If your denture has a softliner, avoid abrasive cleaning actions. Clean your softliner with wet cotton and cold tap water. At night soak in Mersene (sold in Drug Stores). Avoid effervescent cleaning products as they may change the surface of the liner