Preprosthetic Surgery PDF

Preprosthetic Surgery Dr. Manish Bhagania BDS, MDS, FICD, FIBCSOMS Clinical Associate Professor Oral and Maxillofacial Surgery Introduction Despite the improved ability of dentistry to maintain the dentition, many ind...

Preprosthetic Surgery Dr. Manish Bhagania BDS, MDS, FICD, FIBCSOMS Clinical Associate Professor Oral and Maxillofacial Surgery Introduction Despite the improved ability of dentistry to maintain the dentition, many individuals continue to require replacement of some or all of their teeth. Surgical improvement of the denture-bearing area and surrounding tissue (preprosthetic surgery) offers an interesting and demanding challenge to the dental practice. Many minor modifications of the alveolar ridge and vestibular areas can greatly improve denture stability and retention. Some patients undergo severe bone changes or soft tissue abnormalities that require extensive surgical preparation before the prosthetic appliance can be properly constructed and worn. Jaw Resorption after Tooth Loss Bone is known to be highly dynamic, as it constantly goes through a cycle of regeneration and resorption. In this latter cycle, the osteoclasts break down the body’s bones – including the jawbone – to release needed minerals, such as calcium, into the blood. Jaw bones are known to keep their structure, size, and volume through natural activities such as chewing; however, once the teeth are no longer present, the body thinks that the calcium once in the teeth is no longer needed, which then causes the bone resorption process to occur. During resorption, the bone growth and maintenance stops at the site where a tooth or several teeth are missing. A section of the jaw bone that holds the teeth in the mouth, known as the alveolar bone, will no longer receive stimuli, which then causes bone resorption Effects on Jaws following tooth loos Irregular Alveolar Ridge Undercuts Scarring Mucosal and muscular attachments Effects of Edentulism: Typical overclosed appearance. Neurosensory disturbances. Encroachment of muscle tissues leading to instability. Prolonged effects culminates in pathological fracture. General resorptive changes in an edentulous ridge 1. The ridge is wide enough at its crest to accommodate the recently extracted teeth. 2. The ridge becomes thin and pointed. 3. The pointed ridge flattens to the level of the basal bone. 4. The flattened ridge becomes concave as the basal bone resorbs. Mercier P. Residual alveolar ridge atrophy: classification and influence of facial morphology. J Prosthet Dent. 1979;8:24. Cawood and Howell classification of edentulous jaws Class I—dentate. Class II—Immediately post-extraction. Class III—well-rounded ridge form, with adequate height and width of the alveolar process. Class IV—knife-edge form with adequate height but inadequate width of the alveolar process. Class V—flat-ridge form with inadequate height and width. Class VI—depressed ridge form with evident basal bone loss. Resorption Patterns Maxilla Mandible Objectives of Preprosthetic Surgery 1. Provide a stable base through either augmentation or maintenance of the alveolar ridge at the time of surgery or alveolar ridge reconstruction after surgery. 2. Remove hard and/or soft tissue protuberances, such as frenum, tori, or hyperplastic tissue, that may interfere with either insertion, retention, or stability. 3. Establish or maintain a sufficient vestibular depth to allow for denture flange for stability and retention. Preprosthetic Surgical Procedures Ridge correction procedures Hard-tissue correction Alveoloplasty Alveolectomy Tori/Torus Reduction Reduction of Genial Tubercle/Mylohyoid Ridge/Maxillary Tuberosity Soft-tissue correction Frenotomy/Frenectomy Excision of Excess tissue Ridge extension procedures - Vestibuloplasty Ridge Augmentation Procedures Patient Evaluation and Treatment Planning No preparatory surgical procedure be undertaken without a clear understanding of the desired design of the final prosthesis Esthetic and functional goals of the patient must be assessed carefully and a determination made as to whether these expectations can be met Medical & Surgical History, Medications, Allergies, Psychological Assessment Information on success or failure with previous prosthetic appliances may be helpful in determining the patient’s attitude toward and adaptability to prosthetic treatment Intra Oral Examination Visual inspection Ridge contour Undercuts Muscle attachment Lack of adequate interarch space Soft tissue health Palpation Denture bearing areas might reveal sharp bony areas Inadequate hypermobile tissue Radiographic examination Needed to rule out bony pathology If it decided to leave retained roots, it should be notified to the patient atrophic mandibular and maxillary alveolar ridges pneumatization of the maxillary sinus CBCT: detailed cross-sectional anatomy of the mandible Recontouring of Alveolar Ridges Simple Alveoloplasty Associated With Removal of Single Toothth eliminates buccal irregularities and undercut areas by removing labiocortical bone Alveoloplasty Associated With Removal of Multiple Teeth Intraseptal Alveoloplasty (Dean technique) Removal of intraseptal bone and the repositioning of the labial cortical bone, rather than removal of excessive or irregular areas of the labial cortex. Best used in an area where the ridge is of relatively regular contour and adequate height but presents an undercut to the depth of the labial vestibule because of the configuration of the alveolar ridge Can be accomplished at the time of tooth removal or in the early initial postoperative healing period the labial prominence of the alveolar ridge can be reduced without significantly reducing the height of the ridge in this area periosteal attachment to the underlying bone can also be maintained thereby reducing postoperative bone resorption and remodeling the muscle attachments to the area of the alveolar ridge can be left undisturbed in this type of procedure main disadvantage of this technique is the decrease in ridge thickness Maxillary Tuberosity Reduction (Hard Tissue) Horizontal or vertical excess of the maxillary tuberosity area may be a result of excess bone, an increase in the thickness of soft tissue overlying the bone, or both Preoperative radiograph or selective probing with a local anesthetic needle is often useful to determine the extent to which bone and soft tissue contribute to this excess and to locate the floor of the maxillary sinus. Recontouring of the maxillary tuberosity area may be necessary to remove bony ridge irregularities or to create adequate interarch space, which allows proper construction of prosthetic appliances in the posterior areas. Maxillary Tuberosity Reduction (Soft Tissue) Primary Objective:  provide adequate interarch space for proper denture construction in the posterior area  firm mucosal base of consistent thickness over the alveolar ridge denture-bearing area. Mandibular Retromolar Pad surgery is very similar Buccal Exostosis and Excessive Undercuts Excessive bony protuberances and resulting undercut areas are more common in the maxilla than in the mandible Although extremely large areas of bony exostosis generally require removal, small undercut areas are often best treated by being filled with autogenous or allogeneic bone material Palatal Exostosis Tori Removal (Maxillary/Palatal) Tori may have multiple shapes and configurations, ranging from a single smooth elevation to a multiloculated pedunculated bony mass. Tori present few problems when the maxillary dentition is present and only occasionally interfere with speech or become ulcerated from frequent trauma to the palate. Occasionally, though Tori have to be removed for coverage in the prosthesis design Suture Breakdown Flap Necrosis Hematoma Formation Palatal Perforation Fracture ?? Recurrence Tori Removal (Mandibular) Other rare procedures Genial Tubercle Reduction Mylohyoid Ridge Reduction Removal of Soft Tissue Excess Before the excision of this tissue, a determination must be made whether the underlying bone should be augmented with a graft. If a bony deficiency is the primary cause of soft tissue excess, then augmentation of the underlying bone is the treatment of choice. If adequate alveolar height remains after reduction of the hypermobile soft tissue, then excision may be indicated. Palatal Extensions Hypermobile tissues Inflammatory Hyperplasia Frenum Inflammatory Hyperplasia Also called epulis fissurata or denture fibrosis Generalized hyperplastic enlargement of mucosa and fibrous tissue in the alveolar ridge and vestibular area, which Most often results from ill-fitting dentures Nonsurgical treatment with a denture adjustment in combination with a soft liner is frequently sufficient for reduction or elimination of this tissue initially. Treatment When the area to be excised is minimally enlarged, electrosurgical or laser techniques provide good results for tissue excision. If the tissue mass is extensive, large areas of excision using electrosurgical techniques may result in excessive vestibular scarring. Simple excision and re-approximation of the remaining tissue is preferred. A surgical splint or denture lined with soft tissue conditioner is inserted and worn continuously for the first 5 to 7 days, with removal only for oral saline rinses. Secondary epithelialization usually takes place, and denture impressions can be made within 4 weeks. Laser excision of large epulis allows complete removal without excessive scarring or bleeding. A soft relined denture can provide for additional postoperative comfort from a procedure that initially creates minimal pain Labial Frenectomy Level of frenal attachments may vary from the height of the vestibule to the crest of the alveolar ridge and even to the incisal papilla area in the anterior maxilla Movement of the soft tissue adjacent to the frenum may create discomfort and ulceration and may interfere with the peripheral seal and dislodge the denture Surgical Techniques: (1) Simple excision technique (2) Z-plasty technique } mucosal and fibrous tissue band is relatively narrow (3) Localized vestibuloplasty with secondary epithelialization (4) Laser-assisted frenectomy Simple Excision Method Z-Plasty Technique Localized vestibuloplasty with secondary epithelialization Wider Base Supraperiosteal Dissection Lingual Frenectomy Immediate Dentures Offers immediate psychological and esthetic benefits to patients Also functions to splint the surgical site, which results in the reduction of postoperative bleeding and edema and improved tissue adaptation to the alveolar ridge Vertical dimension can be most easily reproduced with an immediate denture technique Disadvantages include the need for frequent alteration of the dentures postoperatively and the construction of new dentures after initial healing has taken place ADVANCED PREPROSTHETIC SURGICAL PROCEDURES Transpositional Flap Vestibuloplasty (Lip Switch) Vestibule and Floor-of-Mouth Extension Procedures Submucosal Vestibuloplasty Maxillary Vestibuloplasty With Tissue Grafting Segmental Alveolar Surgery in the Partially Edentulous Patient Reference Thank You