Partially Edentulous Conditions

In cases where in the mouth teeth are missing, edentulous situations are grouped in 4 categories that were defined by Dr. Edward Kennedy in his classification of partially edentulous arches.

• Class I (bilateral free ended partially edentulous)
• Class II (unilateral free ended partially edentulous)
• Class III (unilateral bounded partially edentulous)
• Class IV (bilateral bounded anterior partially edentulous)

Kennedy Class I
This type is for people who are missing some or all of their teeth on both sides in a single arch and there are no teeth posterior to the edentulous area. Class I RPD´s clasp onto the teeth are more towrds the front of the mouth, while replacing the missing more back of the mouth teeth on both sides with false denture teeth.

Class II
RPD´s are fabricated for people who are missing some or all their posterior teeth on one side in a single arch, and there are no teeth behind the edentulous area. Thus, Class II RPD´s clasp onto teeth that are more towards the mouth, as well as on teeth that are more towards the back of the mouth of the side on which teeth are not missing, while replacing the missing more back of the mouth teeth on one side with false denture teeth.


Class III
RPD´s are fabricated for people who are missing some teeth such that the edentulous area has teeth remaining both posterior and anterior to it. Unlike Class I and Class II RPD´s which are both tooth and tissue borne, Class III RPD´s are strictly tooth borne, which means they only clasp onto teeth and do not need to rest on the tissue for added support. This makes Class III RPD´s exceedingly more secure as per the three rules of removable prostheses that will be mention later namely: support, stability and retention.

However is the edentulous area described in the previous paragraph crosses the anterior midline, the RPD is classified as a Class IV RPD. By definition, a Kennedy Class IV RPD design will posses only one edentulous area.

Classes I, II and III RPD´s that have multiple edentulous areas in which replacement teeth are being placed are further classified with modifications states that were defined by Oliver C. Applegate. Kennedy classification is governed by the most posterior edentulous are that is being restored. Thus, if for example, a maxilary arch is missing teeth #1,3, 7-10 and 16, the RPD would be Kennedy Class III model 1. It would not be Class I, because missing third molars are generally not restored in an RPD (although if they were, the classification would indeed be Class I), and it would not be Class IV, because modification spaces are not allowed for Kennedy Class IV.

The Occlusal Splints (night-guard)

An occlusal splint or sometimes called night guard is mostly recommended to patients that are heavy grinders, or bruxes*.

Since most of the damage caused by teeth grinding is when we sleep, a splint ussually stops or prevent further damage.

The guard is custom made the upper or lower arch of the mouth. When the night guard is in place, the patient can not grind their teeth together and cause more damage.

The guard is worn during night maybe 4-5 nights a week and has been proved that they reduce the chance of fracture and tooth surface loss in the long run.


*Bruxism is the nocturnal unconscious grinding or gnashing of the teeth. It has been linked to stressful life events and occlusal or bite irregularities. Research shows that the maximun clench force capability during bruxism is up to 4 times the maximun conscious force in some subjects.

What is a dental attachment?

An attachment is a connector that is formed of 2 or more parts. One part is connected to a root, tooth, or implant and the other part to a prosthesis. There are certain exceptions as some attachments have only one manufactured part and the other part must be made by the dentist or the dental technician.

Attachments can be divided into two categories: Precision and Semi-Precision. We will examine both of them prior to attachment consideration.

Precision Attachments

Precision attachments are just that - "precision". Their components are machined in special metal alloys under precise tolerances. These tolerances are within 0.01 mm. Since the specific hardness of the alloys is controlled, precision attachments offer the advantage of less wear on the abutments, and standard parts which allows the components to be interchangeable, and usually easier to repair when necessary.
Semi-Precision Attachments

A semi-precision attachment is fabricated by the direct casting of plastic, wax, or refractory patterns. Most semi-precision attachment patterns are injection molded to reduce the overall cost. They are considered "semi-precision" since in their fabrication they are subject to inconsistent water/powder rations, burn out temperatures, and other variables. The resulting components therefore, vary to a small degree.

Their main advantages are: economy, easy fabrication and ability to be cast in a wide choice of alloys without the problem of co efficiency differences between the cast alloy and the machine alloy.


http://www.attachments.com/

What Are Dental Implants?

To make an exact replica of the natural function and look of the missing tooth it's a hard mission to accomplish. Throughout history, people have tried dentures or ceramic restorations as replacements, but in the end the results are not satisfactory for many. That is why dental implants came into existence, offering a more natural look and the same function as the natural tooth root. They have also been used to anchor dentures and ceramic restorations with greater success and patient satisfaction.

A dental implant is a small titanium post that works as the root structure for a natural tooth. They are placed either into your upper or lower jaw bone. When implants are integrated to the bone, they can now hold a crown, bridge or over-denture as in the case of natural roots. It is worthy of mentioning that they are very durable and can last a lifetime, with no need for special maintenance but only regular brushing, flossing and dental check ups.

3M Lava Zirconia Crowns

This revolutionary system combines CAD/CAM technology with the best translucent zirconia framework. This enables one to make a strong restoration for long span bridges with an incredible fit and bio-compatibility and the aesthetics patients expect.

In modern society beautiful teeth are important for self-esteem and a sense of well-being. They want teeth that offer value for money, a natural appearance and more durability.

Lava crowns and bridges are made from zirconium oxide (zirconia) and are suitable for anterior and posterior applications for up to 4 units in lenght without any compromise of the lifespan of the restoration. Zirconium oxide combines natural appearance with the exceptional strength. The fracture strenght of a zirconia crown is many times higher than that of the conventional ceramic materials.

Some of the benefits of 3M Lava Zirconia are these:

Higlights:

• Superior strenght of zirconia with high fracture resistance
• Excellent aesthetics and translucency
• Oustanding marginal fit

Material Composition:

• Zirconium Dioxide substructure
• Ceramic layering material

Applications:

• Anterior: crown, 3-8 unit bridge
• Posterior: crown, 3-8 unit bridge, inlay onlay, inlay bridge

Flexural Strenght:

• >1000 MPa

Cementation:

• Conventional cement
• Resin cement
• Resin-reinforced glass ionomer
  

Dental Crowns

Dental Crowns are designed for teeth that are damaged and need to be replaced for a ceramic crown. The crowns use the tooth previously prepared to receive a covering or core that can be made of metal, metal-ceramic and all ceramic.

Metal Crowns


Although they are made mostly of precious metals like gold, silver or other alloys, they have a small inconvenient... the colors of the metals and the shine of them make they very visible and obvious to other people. What is worth to mention about them is that their lifetime is long and for patients with a strong jaw they are the best.

Metal Ceramic Crowns


This crowns that fuse porcelain to metal are the second strongest crowns available and they last longer too. We have to say that because the metal being colored by a paste opaque material the reflective quality of them is poor, but when the porcelain is applied by a master in ceramic they look really good.

All Ceramic Crowns


They are made of porcelain, resins or other dental materials. What is outstanding about them is that they look 100% natural on the mouth if you compare them with the other 2 types. Dentists normally suggest this type of crown for front teeth. Although they look better on you, they are fragile and are destined to fail if the pillars where they will be placed are not properly prepared.