BDS 11080 single denture.pdf

BDS11080 Single Denture Date : / / Definition A Single Denture is A complete denture that occludes against some or all natural teeth, a fixed restoration, or previously constructed removable partial denture or complete denture A single complete denture is a complete denture that occludes against...

BDS11080 Single Denture Date : / / Definition A Single Denture is A complete denture that occludes against some or all natural teeth, a fixed restoration, or previously constructed removable partial denture or complete denture A single complete denture is a complete denture that occludes against some or all natural teeth, a fixed restoration or a previously constructed removable partial denture or a complete denture (GPT-1) Indications • It is indicated when it is to oppose one of the following: • Natural teeth that are sufficient in number not to necessitate a fixed or removable partial denture • A partially edentulous arch in which missing teeth has been or will be replaced by removable partial denture • A partially edentulous arch in which missing teeth have been or will be replaced by fixed partial denture Various Combinations of Single Denture Edentulous mandible opposing dentate maxilla Completely edentulous maxillary arch opposing a partially edentulous arch and a removable partial denture Single maxillary complete denture opposing natural dentition Single complete denture opposing an existing complete denture Edentulous mandible opposing dentate maxilla •Conventional single mandibular dentures are contraindicated because they cause severe ridge resorption. In the past years many prosthodontists recommended extraction of the remaining maxillary teeth but this was an aggressive decision!!!!!!! Today other options are available as using Soft liner to reduce the stresses from the opposing natural teeth on the edentulous ridge or constructing an Implants supported mandibular overdenture Factors that make the mandibular single denture a challenging situation are • The excessive force of the natural teeth on the lower ridge which may lead to severe mandibular ridge resorption • Poor stability of the lower denture due to tongue movement • Minimal availability of mucosa with tightly attached submucosa which leads to stress concentration, so the tissues become less tolerable to the forces exerted by the denture Edentulous maxilla opposing a partially edentulous mandible and a removable partial denture The following should be considered in this case • Remaining mandibular teeth should be healthy • The partial denture should meet the minimal acceptance requirements • The occlusal plane, tooth arrangement, esthetic and material composition of the RPD should be suitable to oppose a complete denture • Its always wise to construct both dentures together at the same time Single complete denture opposing an existing complete denture You have to ask the following questions: 1. How long have this existing denture been in use? 2. Was it an immediate denture? 3. does the existing denture meet the requirements of an acceptable denture? Edentulous maxilla opposing natural dentition ➢ Malposed, tipped or super-erupted teeth interfere with balanced occlusion ➢ The imbalance may produce soreness of the mucosa and ridge resorption as the single denture will tend to get displaced The complications and difficulties related to single denture cases 1- Great force generated by the natural teeth resulting in ridge resorption and hyperplastic tissues. 2- Mallposed, tipped, or super erupted teeth in the lower arch make it difficult to achieve a harmonious balanced occlusion. 3- The presence of the mandibular anterior teeth makes the esthetic and phonetic placement difficult. 4- Combination syndrome and associated changes. 5- Abrasion of the artificial teeth if teeth if porcelain is used. acrylic is used or the abrasion of natural 6- Increase the tendency of fracture of maxillary denture due to occlusal stresses exerted by natural teeth. How to overcome the problems of single denture??? The main problem that faces any prosthodontist is the occlusal disharmony of the teeth opposing the complete single denture Common occlusal disharmonies include Overeruption Tilting Rotation Spacing • 1. Missing molar or premolar leading to tilted tooth with distal half super-erupted • Treatment : • Mild: Re-contour • Moderate: orthodontic treatment, root canal treatment or Crowning • Severe: Extract 2. Natural lower cuspids or canines are super-erupted • Selective grinding aiming at providing a definite distal slope on the lower canine so as to allow for free passage of the upper artificial canine between the lower canine and the first premolar in lateral movement Techniques to determine the necessary teeth modification before denture construction I- Swenson’s Technique II-Yurkstas’ Technique III- Bruce Technique IV- Boucher’s Technique I- Swenson’s Technique • Denture teeth are set and when the natural teeth interfere with teeth placement, stone teeth are adjusted and marked on the cast with pencil • The natural teeth are modified using the diagnostic cast as a guide • Disadvantages: • Time consuming as it needs several impressions and mounting before occlusion is finalized II-Yurkstas’ Technique • • • Uses a U-shaped metal occlusal template that is slightly convex on the lower surface The template is placed on the occlusal surfaces of the remaining teeth on the stone cast and cusps are adjusted accordingly and the reduced areas are marked with a pencil The necessary alteration are done on the natural teeth using the cast as a guide III- Bruce Technique • The upper and lower diagnostic casts are mounted in the centric relation record • Modifications are made on the stone cast • A Clear Acrylic Resin Template Is Fabricated Over the Modified Stone Cast. • Check the template in the patient’s mouth for interference on seating and adjust the teeth accordingly • The process is repeated until the template seats properly intraorally IV- Boucher’s Technique 1.Casts are mounted on a programed articulator 2. Teeth are arranged to obtain the best balancing contacts 3.If interferences are present, they are removed by movement of the maxillary porcelain teeth over the mandibular stone teeth and these areas are marked with a pencil 4.Prematurities are identified and removed by grinding the natural teeth. 5.The procedure is repeated for right and lateral excursions until a harmonious balanced occlusion is established. Artificial Tooth Selection 1. Acrylic 2. Porcelain 3. Metal – Amalgam – Cast metal 1- Porcelain teeth : -Wear very slowly and therefore the occlusal vertical dimension is maintained. -Cause rapid wear of opposing natural teeth and may be exposed. -Easily fractured 2. Acrylic resin teeth : -No wear of the opposing natural teeth. - They are the teeth of choice. The major disadvantage of resin teeth is their wear, which results in loss of vertical dimension. 3-Metal Occlusal Surfaces 1. Gold occlusals: can be used to minimize wear of the occlusal surfaces. But expensive and time consuming 2. Amalgam stops: can be inserted into the occlusal surfaces of the acrylic resin denture teeth. Kelly's Combination Syndrome • A series of destructive changes occurs in the jaws of the patient wearing a complete maxillary denture opposed by a mandibular distal extension partial denture • It has been described as “Combination Syndrome” by Kelly in 1972 Maxillary complete denture + Mandibular distal extension RPD Kelly’s syndrome Kelly's syndrome is characterized by 1- Loss of bone from the maxillary anterior edentulous ridge 2- Down growth of the maxillary tuberosities 3- Papillary hyperplasia of the tissues of the hard palate 4- Extrusion of the lower anterior teeth 5- Loss of bone beneath the removable partial denture bases • It usually has other associated changes: 1- Loss of vertical dimension of occlusion 2- occlusal plane discrepancy 3- Development of epulis fissuratum. 4- Poor adaptation of the prosthesis 5- Periodontal changes. The premaxilla undergoes severe resorption and is usually accompanied by the development of fibrous hyperplasia of the maxillary tuberosity. The labial flange of the denture produces a low grade irritation in the surrounding soft tissues, resulting in development of epulis fissuratum, and cause an associated overgrowth of fibrous tissue covering the maxillary tuberosities. Single denture fracture and its management Single denture fracture is common due to ❖Heavy anterior occlusal contact ❖Deep labial frenal notch ❖High occlusal forces due to strong mandibular elevator muscles ❖Flexure of the denture base • The problem of fracture could be overcome by: ➢ Use acrylic resin base reinforced with glass fibers (Frankin P 2005) ➢ Use acrylic resin base reinforced with polyethylene fibers (Ladizesky NH 1994) Reinforcement with metal mesh or glass fiber mesh Cast metal reinforcement Summary • The patient who requires a single denture opposing natural teeth or previously restored arch is a challenging condition for both the patient and the clinician more than a completely edentulous patient. This is due to the biomechanical differences in the supporting structures of the opposing arches • A proper evaluation, correction of the existing factors and proper sequence of denture construction is necessary to give a more stable prosthesis • Care should be taken to guard against singe denture fracture by reinforcing • Implants should be used whenever possible to avoid problems of single denture Reading material: • Students are advised to read details at: • 1. Clinical and laboratory manual of implant overdentures, Hamid R. Shafie. • 2. Prosthodontic treatment of edentulous patients, 13th edition. Zarb, Hobkirk, Eckert and Jacob. (chapter 13) • 3. Textbook of complete dentures, 6th edition. Arthur Orahn, John R. Ivanhoe and Kevin D. Plummer, 2009. (chapter 16)