Single Complete Dentures Flashcards
What are types of s.c.d?
- SCD (single complete denture) opposing natural teeth
- SCD opposing a (preexisting) complete denture
- SCD opposing a removable partial denture
- SCD opposing an overdenture
- SCD opposing an implant supported denture
What are PROBLEMS WITH THE SINGLE COMPLETE DENTURE?
- The remaining natural teeth are often tipped, supraerupted or malposed. This results in an uneven occlusal plane which makes it difficult to obtain a harmonious balanced occlusion. Unfavorable occlusal forces can destabilize the denture causing soreness and ultimately ridge resorption.
- Supraerupted teeth can reduce the space available, making setting of artificial teeth a laborious process.
- A mandibular SCD opposing upper natural teeth is extremely complicated. The reduced surface area of the lower ridge results in excessive forces on the ridge resulting in rapid resorption. The lower SCD is therefore rarely indicated.
- The upper SCD opposing lower natural anterior teeth often results in the combination syndrome (fig. 22-2).
- Occlusal wear is another problem. Acrylic wears quickly when opposing natural teeth. On the other hand, if one uses porcelain teeth to counter this, the porcelain teeth results in the wear of the natural teeth.
- The fixed position of lower anterior natural teeth gives us less flexibility for esthetic placement of upper natural teeth.
- The fixed position of lower natural teeth coupled with the marked resorption of upper natural teeth often places teeth in cross bite relationships as well as other functionally compromised positions.
Talk about Diagnosis and treatment planning and Diagnostic casts
Diagnosis and treatment planning
Mounted diagnostic casts are essential because of the peculiar circumstances of the SCD, especially if natural teeth are present. As mentioned before, a SCD opposing natural teeth often requires modification by grinding with a bur before teeth can be arranged. This requires the construction of diagnostic casts mounted on an articulator with a facebow transfer.
Diagnostic casts In order to avoid mounting twice (diagnostic cast and master cast), the master cast is used for the mounting. A final impression is made of the used to obtain jaw relations and a centric relation record. The cast is edentulous jaw. An occlusion rim fabricated on the master cast is then mounted using a facebow record. The lower dentulous cast is mounted using the centric record. Eccentric records are also made to program the articulator. The mounted casts are used to study and plan the occlusion. It helps us to decide which teeth need modification or even extraction.
What are treatment options in single denture?
§
§
§
§
Extraction - hopeless teeth are extracted. This also includes extremely tilted or supraerupted teeth or third molars or other malpositioned teeth which can cause instability of the denture.
Modification - Almost always some kind of modification is required to harmonize the occlusion. This improved the stability as well as reduces soreness and resorption.
Crowns, inlays, bridges - If more than a moderate amount of modification is required one can consider onlays (to restore tilted molars) or crowns.
Missing teeth can be replaced with bridges with a corrected occlusal plane.
Root canal treatment - Sometimes teeth are so extremely supraerupted that reducing their level would certainly lead to sensitivity or even pulp exposure. In such a case RCT is advised followed by a crown at the new occlusal level (fig. 22-3).
Enumerate tooth modifications methods
Swenson’s method
The Yurkstas
Bruce’s method
Boucher’s method
What are functional chew in techniques?
Stansbury’s technique
Vig’s technique
Sharry’s technique
Rudd’s technique
What is Swanson’s method?
Swenson’s method The maxillary and mandibular casts are mounted on the articulator in centric relation. The denture teeth are set. Any opposing natural teeth which interfere are ground and the area marked by a pencil.
The natural teeth are then modified using the cast as guide. After completion of the modifications, a new cast is made and mounted. If more adjustments are needed the procedure is repeated. Once the operator is satisfied, the denture teeth are reset and prepared for try-in. This technique is simple but it can be time consuming especially if several impressions have to be made.
What’s The Yurkstas technique?
The Yurkstas method He used a metal U-shaped occlusal template (fig. 22-3) which was slightly convex on the lower surface. When placed on the occlusal surfaces of the remaining teeth, the high cusps are easily identified . These are reduced on the stone cast, marked with a pencilMand later reduced in the mouth.
What’s brace method?
Bruce’s method It is quite similar to the other techniques. After makingMall the necessary reductions on the stone cast an acrylic template is made.
This template is used along with a pressure indicating paste to identifyMareas needing modification. The modifications are carried out until the template seats well.
What’s Boucher method?
Boucher’s method Porcelain teeth are set on a programmed articulator to obtain the best possible balanced occlusal contacts. Interferences are removed by rubbing the maxillary porcelain teeth over the mandibular stone occlusal surfaces. The denture is processed. The stone cast is then used as a guide to modify the natural teeth until a harmonious balanced occlusion is achieved.
What’s Stansbury’s technique?
Stansbury described the first functional chew-in technique in 1928 for an upper complete denture opposing lower natural teeth. Compound maxillary rims were used. The buccal and lingual sides were trimmed away leaving a single fin like ridge along the middle (corresponding to the central fossa). Carding wax is added to replace the trimmed portions. The patient is instructed to perform lateral and protrusive movements (eccentric movements).
These movements mold the wax. The compound fin in the middle preserves the vertical height. This is known as a functionally generated occlusion. The occlusion rim is removed from the mouth and stone is vibrated into the generated pathways to obtain a positive stone cast of the generated occlusion. We now have two casts. The original cast is used to set the teeth. The second cast of the generated occlusion is then secured to the articulator after detaching the original cast. Using articulating paper all the interferences are eliminated. The occlusion thus obtained is free of lateral and protrusive interferences.
Talk about Vig’s technique, Sharry’s technique and Rudd’s technique?
Vig’s technique Vig’s technique is quite similar except that he used a resin fin contacting the central fossae instead of compound. The resin fin is used to locate interfering lower cusps. Later, the fin is built up with soft wax and the functional path is recorded (fig. 22-4. A, B & C).
Sharry’s technique He used a wax rim at a slightly higher vertical height. Eccentric movements are made to record the pathways until the correct vertical dimension is reached.
Rudd’s technique Rudd’s technique is quite similar to Stansburys. However, he advocates two maxillary rims - one for the recording the generated occlusion and the other for the try-in. This helps to reduce the number of appointments.
Talk about ARTICULATOR EQUILIBRATION TECHNIQUES
When the denture base lacks stability or the patient is unable to cooperate with the dentist, articulator equilibration techniques may be tried.
The upper cast is mounted on to an articulator using a facebow. Next the lower cast is mounted using a centric relation record. The relationship between the upper and lower casts are studied. (Sometimes it may be necessary to set the posterior teeth in a reverse relationship.) The teeth are arranged. In this technique only the functional cusps (holding cusps) are allowed to contact the central fossa. The inclines of the nonfunctional cusps are then reduced. At the try-in, eccentric records are made and the condylar inclinations are set on the articulator. The teeth are arranged to be as close as possible to balanced occlusion. The denture is processed.
At the time of the delivery a new centric record is made and the balancing is completed taking care not to reduce the holding cusps.
What are types of occlusal materials for single denture?
Acrylic resin teeth
The major disadvantage of acrylic teeth is that they wear easily leading to loss of vertical dimension. However, the wear is preferred to resorption of the ridges or damage to the natural teeth.
Gold
occlusals Gold occlusals are among the best materials to oppose natural teeth. However, they are time consuming to make and are certainly more expensive.
Acrylic resin with amalgam stops
This is a less expensive alternative to gold occlusals. After the balancing is completed, cavities are prepared in the occlusal surfaces of the posterior teeth including as much of the occlusal surface as possible. Amalgam is condensed into the cavity and the articulator closed and moved back and forth and side to side until the incisal pin reestablishes contact with the incisal table. Amalgam inserts reduce the occlusal wear.
Porcelain teeth
Porcelain teeth wear very slowly but are prone to fracture and can cause rapid wear of the natural teeth. They are also difficult to grind and modify.
