Dent-Line of Canada Inc. Toll Free 1-800-896-6544 (for Canada only) 416-858-9865 or Fax No. 416-858-9899

Spring 2003


Inside This Issue
1. Bridge Sectioning Attachment
2. Successful Overdenture Therapy
3. New From Bredent: Master-Sep
4. The Anatomy of Aesthetics
5. Trade News: DNA Test of Dentures Left at Crime Scene Aids Police

Bridge Sectioning Attachment

The bridge sectioning attachment from Bredent can be utilized to anticipate future complications if a retaining abutments fails. During the treatment planning phase of restorative dentistry a positive case can be made for the use of one attachment with two objectives. One, the bridge sectioning attachment is made of a gold alloy male attachment that comes with a closing ring and a titanium screw that enables the dental technologist to assemble a multiple unit segmented bridge. Two, if in the future the abutment distal to the attachment fails and has to be extracted, then the bridge sectioning attachment from the original bridge can be utilized to accept a Vario Soft 3 female attachment that is incorporated in a new removable cast partial. Therefore forward thinking can help in salvaging existing crown and bridge work which can save time and which will not burden the patient financially or cause the inconvenience of excessive appointments. The dental technologist will prepare the master models and dies from an accurate full arch impression, then determine the path of insertion. This attachment compensates for non-paralellism of abutment retainers as well as segmenting bridges. Wax the crown patterns and then place the male in a surveyor with paralleling instrument and position it on the master model. Males should follow the path of insertion and should be positioned over the crest of the ridge. Following the standards of practice, cast and trim the crowns and check proper seating of the crown attachment assembly. After applying the porcelain,the bridge sectioning attachment is polished to a high lustre. Next, fix the closing ring with the titanium screw and cover with modeling resin. The rest of the bridge is waxed up around the modeling resin in order to incorporate the pontic and molar abutments. Using a screwdriver, the titanium screw is removed and set aside for final assembly. The wax up is sprued, cast and finished to the standards of practice. Then, the segmented bridge is assembled, cemented and fixed in place with the titanium screw. After many years, if the molar abutment fails, the bridge can be disassembled and the molar extracted. When the ridge is healed, the existing crowns and attachment will be suitable for a new cast partial utilizing the Vario Soft 3 inserts. Bredent’s extra coronal friction grip slide attachments are adjustable by three different plastic inserts. There is no need for a milled bracing arm support since the stress breaker is already integrated into the overall attachment design, providing the opportunity for the patient to practice good oral hygiene. Patients that have limited manual dexterity when removing and inserting the prosthesis will find that the insertion and removal of extracoronal precision attachments are easier to handle. Also, extracoronal precision attachments are normally resilient and allow for free movement of the prosthesis in order to distribute potentially destructive forces or loads away from abutments to supportive bone and tissue. Three characteristic movements are defined as functional; (i) Hinge; (ii) Vertical and (iii) Rotational. The female retention sleeve can easily be removed with a pointed instrument and a new one replaced effortlessly with the insertion tool. The cast partial can also be rebased utilizing standard techniques. This scenario indicates that the bridge sectioning attachment is an acceptable option for forward thinking treatment planning. Source; Peter T. Pontsa RDT. For further information contact us at 1-800-859-7589 or e-mail us at [email protected]

Successful Overdenture Therapy

It is difficult to over emphasize the significance of dentures to the wearer since they are one of the most challenging aspects of modern dentistry. Where patient satisfaction is concerned, the studies from the University of Florida, College of Dentistry, indicate that psycho social variables, such as pre-treatment, expectations, satisfaction with the dental care received and positive mental health showed a strong relationship to a successful outcome. Patients are looking for a well made complete denture with stability and retention. Rapid deterioration of the alveolar ridge is the source of the problem for retention loss. Using existing roots as anchors for an over denture is a low cost treatment option over implant therapy. Implant treatment can be ruled out if there is only inter occlusal space for bar placement which leads to significant increases in denture thickness, a factor which can adversely affect function and speech. Proper candidates should be selected for implant bar therapy. Root supported over dentures can solve the problems of retention, stability and dislodgement while preventing bone loss and preserving the alveolar ridge. Only those candidates with a healthy periodontal environment should be selected for this type of therapy. Endodontic treatment is indicated in the preparation of an overdenture abutment while a healthy periodontal ligament is essential. Requirements of position may be predetermined as to what is available to proceed with. Two cuspids are usually the most common, however there can be other variations when considering cross arch stablization of the overdenture. One attachment that is most readily used is the VKS-OC stud type that is retained directly on the free standing roots. It has a hinging motion that allows the denture to rotate over the stud and permits contact of the gingiva mucosa. This action distributes the force or load over the mucosa and away from the root borne abutment. As wear increases on both plastic and metal parts, the retention sequence allows longer attachment life. The VKS-OC attachment studs come in two sizes, the standard is 2.2 mm in diameter and the mini, which is 1.7 mm in diameter. The mini can fit into very small lateral or central incisor root abutments or in areas with limited vertical dimension. Over all advantages of improved stability, retention and preservation of the aveolar bone make attachment treatment a successful overdenture therapy. Source; Peter T. Pontsa RDT

New From Bredent: Master-Sep

Master-Sep is one of the leading separating mediums in the market today. It is excellent for separating plaster from die stone. It seals the pores of the die stone, this in turn forms a tough protective coating that creates a smooth surface which gives excellent separation. The smooth flow of stone accurately duplicates every detail of the surface and gives a cleaner breakout thus making Master-Sep a perfect insulator and separator between the dental arch and the model base. For further information or pricing call us at 1-800-859-7589. Source; Dent-Line of Canada Inc. For more information and pricing call us at 1-800-859-7589 or e-mail us at [email protected]

The Anatomy of Aesthetics

The fabrication of dentures is both a science and an art form. The anatomy of aesthetics can be defined as the way in which teeth are to be replaced and is critical to any major transition from natural to artificial teeth. An average patient’s concerns about appearance, aesthetics and how they look to others is the single most important outcome when fabricating complete dentures. Ideally the basic objective is not just to restore missing teeth aesthetically, but to restore the complete person to a healthy and happy individual. There are a number of contributing factors that should be reviewed starting with “naturalness”. Elements that influence naturalness are position, dimension, alignment, form and shade.

Position: Tooth position is a bio-mechanical exercise that dictates lip support and determines the firmness of muscle tone for facial muscle activity.

Dimension: The clinical practicioner must carefully explain and guide the patient into recognizing there is a harmonious relationship between the size of anterior teeth and the size of the face. Long teeth create at toothy appearance, small teeth on the other hand shows excessive pink gingival. Scientific investigation indicates that the upper central should be one sixteenth the facial width for an optimum pleasing appearance. Individual studies indicate that stock teeth may be too uniform and it would be prudent to select central, laterals and cuspids individually rather than from the carded set provided by some tooth manufacturers.

Shade: Consider the patient’s age and complexion and select teeth with several shades to give each tooth a distinctive colour and texture. The closer an object is to the eye, the lighter it seems. Therefore, professional guidance is necessary to provide the patient with a tentative colour selection and get final acceptance at the try-in stage.

Form: There is clinical evidence to indicate that harmony between tooth form and the shape of the face is the exception and not the rule. The system of classifying faces as square tapering and avoid the corresponding carded tooth system attributed to it, may be easy to use and is widely accepted by the dental profession, however, it has no aesthetic merit or scientific basis. Since there is a lack of natural standardization and the fact the edentulous arches are changing due to tooth removal, surgery and restoration, mold selection whether square tapered or avoid cannot be selected by the from of the residual ridge. According to A. Nelson, the unchanging from of the central position of the palatal vault is the most reliable clue to the original from of the arch. Therefore, correct alignment is far more important than correct mold of tooth for the patient.

Alignment: Arrangement is the most dominating factor related to teeth and their aesthetic influence. The only correct tooth position is where teeth were in nature. Start with the maxillary centrals which are always in front of and on either side of the incisive papilla. Don’t position upper anterior teeth on top of the ridge crest since it will cause facial functional loss. Also, analyze both the vertical tooth position and the labio- lingual position while establishing phonetics. The patient’s old dentures provide a lot of information or a photograph showing the natural teeth in a smile is also welcome. Alignment in relating teeth in their long axis or breaking their alignment follow examples found in natural teeth. From studying natural dentition we can conclude there is a definite relation between the form of the maxillary arch and the alignment form of the upper anterior teeth. The arch then indicates the alignment of the natural teeth.

Final Waxing: the polished surface area of a complete denture influences retention as well as aesthetics. The wax around the teeth should indicate the form of the gingival tissues. Labial surface fullness is desirable without altering the original borders. The lower denture lingual surface should be concave to provide a resting place for the tongue. Some festooning can create a natural look. There is no fool proof formula for achieving a perfect result, however, each clinician following accepted standards of practice can ensure patient satisfaction and make this experience more enjoyable and rewarding for all concerned. Source; Peter T. Pontsa RDT, for additional information contact Dent-line of Canada Inc. at 1-800-859-7589 or 416-499-6954.

Trade News: DNA Test of Dentures Left at Crime Scene Aids Police
A British gang decided to steal an ATM machine. The plan was for the ring leader to crash his Rover 2000 through the building’s front door. Unfortunately for him, he hit the entrance way so violently that his false teeth flew out. With police hot on their heals, the villains were unable to retrieve the dentures before fleeing. The police technicians, discovered the dentures, ran a DNA test on the uppers and were able to identify the leader which led to his subsequent arrest. Source; Road & Track, January 2003