PREIMPLANT PROSTHODONTICS Rola Shadid BDS, MSc, AFAAID The existing tooth and arch relationships do not need to be perfect before implant treatment. The.
Download ReportTranscript PREIMPLANT PROSTHODONTICS Rola Shadid BDS, MSc, AFAAID The existing tooth and arch relationships do not need to be perfect before implant treatment. The.
PREIMPLANT PROSTHODONTICS Rola Shadid BDS, MSc, AFAAID The existing tooth and arch relationships do not need to be perfect before implant treatment. The correct tooth positions should be first determined, so even if the total treatment time is extended over several years, at least each segment will aim toward a consistent goal. Although it is easier to restore an entire mouth to the correct occlusal relationships at one time, it is also possible to obtain a similar result one tooth at a time as long as each step proceeds along the predetermined course of the overall treatment. The idea treatment ideal 1. Address the patient’s chief complaint. 2. Provide the best option for long lasting care with the understanding that nothing in dentistry is permanent. 3. Be cost effective if possible. This is not to mean it needs to be inexpensive. 4. If possible, the treatment should meet or exceed the patient’s expectations. Torrabinijad and Goodachre in JADA OVERALL EVALUATION Overall Evaluation Maxillary anterior tooth position Occlusal vertical dimension Mandibular incisal edge Maxillary posterior plane Mandibular posterior plane MAXILLARY ANT. TEETH POSITION No other region of the mouth should be restored until this position is corrected because it negatively influences the proper position of every other segment (e.g., OVD, mandibular anterior tooth position, and posterior planes of occlusion) MAXILLARY ANT. TEETH POSITION if their position is undesirable for any reason, orthodontics or restoration may be indicated. The evaluation is not for the cosmetic aspects, but tooth position is scrutinized. If the maxillary incisor edge is modified in either the horizontal or vertical plane, all other four elements of stomatognathic system may also need to be changed. MAXILLARY ANT. TEETH POSITION The labial position of the max ant. teeth is first determined with the lip in repose. Overall support of the maxillary lip and its relationship to the nose and presence or absence of a philtrum in the midline Labial position of the max ant. teeth Labial position of the max ant. teeth Labial position of the max ant. teeth Touches wet line of lower lip when ‘F’ or ‘V’ sounds MAXILLARY ANT. TEETH POSITION The vertical position of the max ant. teeth canine tip is located 1 mm level with the lip in repose, regardless of age or sex of the patient. The centrals are 1 to 2 mm longer than canine. EXISTING OCCLUSAL VERTICAL DIMENSION (OVD) OVD: the distance between 2 points (one in max and the other directly below in the mandible) when the occluding members are in contact. OVD requires clinical evaluation not diagnostic casts. OVD is not a precise dimension, because a range of dimensions is possible without clinical symptoms. OVD often decreases over time without clinical consequence in the dentate or edentulous patients. OVD affects on: Esthetics of the chin to face position Any change in OVD affects the CHS. Any change in OVD modifies the horizontal dimensional relationship of the maxilla to the mandible. change in OVD will modify anterior guidance and range of function. The more closed the OVD, the farther forward the mandible rotates and the more skeletal class III the chin appears . The most important effect of OVD on teeth and implants is the effect on the biomechanics of anterior guidance. Change in OVD may affect the sibilant sounds by altering the horizontal position of the mandible. OVD Vs facial esthetics OVD Vs. CHS OVD Vs. Anterior Guidance • Asthe mandible moves downward As mandible opens (ie. by (opening or increasing increasing the occlusalOVD) vertical dimension) edge moves • Incisal the edgeincisal moves back downward and backward. By • Increases overjet increasing the vertical dimension, Class and III there is more• Helpful overjetAngles is obtained a tendency toward • Problem Anglesmoving Class II to a skeletal Class II situation. Incisor guidance is necessary to decrease the risk of posterior interferences during mandibular excursions (protrusion). Decreasing the incisal guidance increase force on posterior implants during mandibular excrusion. Steepening the incisal guidance (increasing the vertical overlap of the anterior teeth) increase force on anterior implants Methods for evaluating OVD SUBJECTIVE METHODS Physiologic rest position (PRP) Phonetics as a guide Esthetics as a guide OBJECTIVE METHODS: use facial dimensions Experienced clinicians often use subjective method to assess OVD. The objective method is usually the method of choice to evaluate existing OVD or establish a different OVD during prosthetic reconstruction. Subjective Methods of Assessment of OVD 1. Measuring the physiologic rest position (PRP) 2. Feeling for interocclusal distance (ID) by ensuring movement of mandible 3. Phonetics as a guide 4. Esthetics as a guide 1. Measuring the PRP * PRP = ID + OVD Patient sitting bolt upright PRP affected by posture Measurements OVD & PRP Use external points for ease of measurement Small dots under columella & midsymphisis Use Boley Gauge, not ruler Measuring Physiologic Rest Postion (PRP) Open and close until lips barely touch - Physiologic Rest Position (PRP) Measure distance between dots Measuring Occlusal Vertical Dimension Open and close until teeth/rims touch Measure distance between dots (OVD) Measurement will be different each appointment Measure the distance between dots At PRP At OVD Difference is ID Measurements change each day (position of dots) 2. Feeling for Interocclusal Distance by ensuring movement of mandible Close until lips barely touch - PRP Place finger on chin Look away Patient closes until rims touch (OVD) Feel for movement of the mandible 3. Using Phonetics As A Guide m sound: patient repeats the letter m and the distance between two reference points are measured. The occlusion rims adjusted so that they are 2 to 4 mm short of this position when they are occluded ch, sh, j, s, z sounds: at right vertical height there should should not be more or less than 1 to 2 mm space between upper & lower occlusion rims Closest speaking space * Fricative sounds (f, v, ‘Fifty-Five’ , ask patient to count from 50 to 60) - upper incisal edges should JUST touch the posterior one third of the lower lip 4. Esthetics As A Guide Assessment of facial proportion, expression & esthetics. If the face appears strained, the OVD may be too much If the corners of the mouth droop, making chin appear too close to nose, the OVD may be too less Objective Methods of OVD Assessing Situations that altering OVD is mandatory 1. Esthetic & incisal edge position, facial balance, occlusal plane. 2. Function & canine position, incisal guidance, angle of load to teeth or implants. 3. Structural needs of the dentition & dimensions of teeth for restoration while maintaining a biologic width 4. To increase CHS MANDIBULAR INCISOR EDGE POSITION Mandibular incisor edge should contact the lingual aspect of maxillary anterior natural teeth at the desired OVD position. In a full-arch maxillary and mandibular overdenture, and maxillary denture, no anterior contact in centric relation (CR) occlusion is designed 3- to 4-mm vertical overlap for implant restoration INCISAL GUIDANCE influence of contacting surfaces of the mandibular and maxillary anterior teeth on mandibular movements. CHRISTENSEN’S PHENOMENON Incisal Guidance Angle The angle formed by the intersection of the plane of occlusion and a line within the sagittal plane determined by the incisal edges of the maxillary and mandibular central incisors when the teeth are in maximum intercuspation Incisal Guidance Angle ↓ Incisal Guidance Angle by ↑ horizontal overlap IG is evaluated on the mounted diagnostic casts. A steep IG 1)avoid post interferences during mandibular excursions, 2) greater forces on anterior crowns EXISTING OCCLUSAL PLANES The position of occlusal planes relates to the curve of spee and wilson ( the radius of a 4 inch sphere). Ideally, the maxillary posterior occlusal plane should be parallel to the Camper's plane . Odontoplasty, endodontic therapy, functional crown lengthening, and crowns are indicated to remedy tipping or extrusions of adjacent or opposing natural teeth. A pretreatment diagnostic wax-up is suggested to evaluate the needed changes before implant placement An occlusal plane analyzer may be used on diagnostic casts to evaluate pretreatment conditions and assist in intraoral occlusal plane correction. The natural dentition opposing a partially edentulous ridge also must be carefully examined and often needs modification before surgical placement of the implants. The implant drills and implant body insertion often require a posterior CHS of more than 8 mm from the ideal occlusal plane. SPECIFIC CRITERIA SPECIFIC CRITERIA Smile line Pretreatment Analysis of Edentulous Maxilla Occlusal facors Maxillomandibular arch relationship Existing occlusio Arch form Parafunctionl habits CHS TMJ status Existing prosthesis Implant Site Assessment Natural teeth adjacent to implant site (Existing of hopeless teeth) Soft tissue evaluation of the edentulous site. Behavioral factors & habits Smile Line Number of teeth displayed in the horizontal dimension in a broad smile Number of teeth displayed Pretreatment Analysis of Edentulous Maxilla Pretreatment Analysis of Edentulous Maxilla Presence or Absence of a Composite Defect Visibility of the Residual Ridge Crest (Transition line) Composite Defect Assessment Duplication of the confirmed denture or tooth set-up using a transparent acrylic resin Composite Defect Assessment With a satisfactory denture, thickness of the maxillary denture base and flange can be used to assess the presence or absence of composite defect. A thick denture base and flange indicate moderate to advanced resorption of the maxilla. A thin denture base and a very thin or absent flange a “tooth-only defect” is present. Visibility of the Residual Ridge Crest Visibility of the edentulous ridge crest at rest and during animation To maximize the esthetic result of a prosthetic, the clinician must evaluate the potential for visibility of the transition between the prosthesis and the soft tissue of the edentulous maxillary ridge without the maxillary denture in place, both in the anterior maxilla and the buccal corridor. Visibility of the Residual Ridge Crest If the patient does display the residual ridge soft tissue crest while smiling, the transition between an implant restoration and the soft tissue will be visible, and the esthetic consequences of this depend on whether the patient also has a composite defect. A transition line that is hidden during animation results in an esthetically pleasing outcome Management of residual ridge soft tissue display during smiling? For tooth-only defect, a metal-ceramic restoration can be used, and the visible gingiva will improve the esthetics rather than detract from them. This assumes that the implants are placed in planned tooth positions. Management of residual ridge soft tissue display during smiling? When a composite defect is present, a metal-ceramic, tooth-only restoration will result in an esthetic compromise because the teeth will appear longer than normal. If FP3 is used, the junction of the artificial gingiva and the natural soft tissue will be visible, and the differences in texture and contour between the two may be obvious and unesthetic Management of residual ridge soft tissue display during smiling? One method for avoiding a visible transition line is to initially reduce the residual ridge height through an alveolectomy and or alveoloplasty to a point at which the crest is no longer visible Or use a prosthesis with a flange such as overdenture or a fixed-detachable Marius bridge with a flange that overlaps the gingival junction Transition Line should be apical to Smile Line You Should Hide Transition Zone if composite defect Transition line evaluation reveals a visible anterior sextant and hidden bilateral buccal corridor transition lines. Composite defect with visible transition line This needs alveoloplasty of the anterior maxilla to position transition line more apical to the smile line Unesthetic Determination height of the maxillary ant. teeth 1. Establishing incisal edge by the lip in repose. 2. The high smile line determines the height of the tooth (9-12 mm) 3. Cervical necks lie at or above this line 4. The width of the anterior teeth is determined by the height/width ratios. CROWN HEIGHT SPACE CROWN HEIGHT SPACE CHS= distance between bone level and occlusal or incisal plane. IDEAL CHS for FP1 implant 8 -12 mm. Angled force, high CHS, angled implant placement force magnifier. Ideal CHS for removable prostheses is greater than 14 mm, and the minimum height is 10.5 mm. CHS is a vertical cantilever when any lateral or cantilevered load is applied and, therefore, is also a force magnifier Excessive CHS Greater than 15 mm Causes: long term edentulism , genetics, trauma, and implant failure Treatment of excessive CHS before implant placement includes orthodontic and surgical methods. Orthodontics in partially edentulous patients is the 72 method of choice Surgical techniques block onlay bone grafts particulate bone grafts with titanium mesh or barrier membranes distraction osteogenesis Misch presented a unique approach combining vertical distraction and horizontal onlay bone grafting to reconstruct the deficiency threedimensionally. Osseous distraction is performed first to vertically increase the ridge and expand the soft tissue volume. Secondarily an onlay bone graft is used to complete the repair of the defect (Figure 629) 74 FP-3 is rarely the treatment of choice for single tooth replacement. Stress reducing options 1. Shorten cantilever length 2. Minimize offset loads to the buccal or lingual 3. Increase the number of implants 4. Increase the diameters of implants 5. Design implants to maximize the surface area of Implants 6. Fabricate removable restorations that are less retentive and incorporate soft tissue support 7. Remove the removable restoration during sleeping hours to reduce the noxious effects of nocturnal Parafunction 8. Splint implants together, whether they support a fixed or removable prosthesis 76 Reduced CHS Inadequate bulk of restorative material for strength or esthetics, and poor hygiene conditions compromising longterm maintenance Increased material flexibility Reduction of retention Difficult access for implant surgery How to Increase CHS? Restore the proper OVD Osteoplasty and soft tissue reduction of one arch when the opposing teeth are in the correct OVD and centric occlusion position Osman et al. J Oral Implant. 2014 Dealing with Reduced CHS Less than 3 mm of abutment height indicates a screw retained crown, 3 to 4 mm requires a screw retained or resin-cemented restoration, and greater than 4 mm of abutment height allows the operator's preference. It is better to use metal in occluding surfaces in reduced CHS Splinting implants together, regardless of whether they are screw retained or cement retained, can also increase retention. Occlusal Factors Occlusal Factors Maxillomandibular arch relaionship Incisor, canine and molar occlusion classification Maximum intercuspation vs centric relation Lateral guidance (canine or group function occlusion) Eccentric interferences Arch curvature and shape Parafunctional habits MAXILLOMANDIBULAR ARCH RELATIONSHIP In cases of extreme class II or III, surgical correction may be needed Palatal resorption of the maxilla with the anterior rotation of the mandible mimic Class III relationship->> can contribute significant lateral forces on the maxillary restoration-> additional splinted / implants are suggested in the maxilla with the widest A-P distance available. MI Vs CR MI : complete intercuspatin of opposing teeth independent of condylar position. CR: occlusion of opposing teeth when mandible is in CR. Slide between MI & CR The more teeth replaced or restored, the more likely the patient restored to CR occlusion. Lateral Guidance Non-working side interference When we need occlusal correction before restoration of the implant patient? Negative symptoms related to the existing condition, TMJ conditions, tooth sensitivity, mobility, wear, tooth fractures or abfraction, or porcelain fracture. The fewer and less significant the findings, the less likely an overall occlusal modification is required before restoration of the patient. Occlusal factors-Parafunctional habits 75% failures due to bruxism (Balshi 1997) All implants failures were in patients with parafunctional habits (Jaffin 2000) Not a contraindication? But careful treatment plannig TMJ examination Muscles of mastication Deviation to one side during opening Noises or clicking in the joint during opening Maximal opening The range of opening without regard to overlap or overbite ranges from 38 to 65 mm in men and 36 to 60 mm in women, from one incisal edge to the other Arch Form Square, ovoid, and tapering Ridge vs dental arch form Arch Form Anterior Cantilever (mm) Number of Implants Implant Position Square <8 2 Canines 3 Two canines and one incisor 4 Two canines and two incisors Ovoid Tapering 8-12 >12 Square Ovoid Tapering Treatment Prostheses Reestablish or evaluate the OVD, evaluate esthetic considerations, or treat TMJ dysfunction Implant Site Assessment Implant Site Assessment Mesiodistal space assessment Ridge mapping Biotype analysis Width of attached gingiva Periodontal probing Bone sounding Mesiodistal space Soft tissue Biotype analysis Thick/flat tissue type Thin gingiva Wide band of KG Short square teeth Thin/scalloped tissue type Thick gingiva Narrow band of KG Long tapered teeth Olsson 1993 J Clinc Period Kan 2003 Attached Gingiva Bone sounding Interproximal papillae are expected to fill the embrasure area if the distance between the contact points to the interproximal crestal bone is 5 mm or less. Evaluation of teeth adjacent to implant site Hopeless teeth should be extracted and teeth with advanced periodontal or endodontic conditions treated before determining the final implant restoration and the implant position and number A tooth may be considered for extraction because of prosthetic, endodontic, periodontal, or surgical considerations. Prosthetic Considerations Prosthetic Considerations Prosthetic Considerations A patient with a history of high decay rate, and recurrent caries under crowns requiring endodontics with a post and core before restoration, may be better served with an extraction and implant insertion Endodontic Considerations Apicectomy in the posterior mandible has a moderate to high risk of paresthesia Endodontic Considerations Devital teeth with >5mm apical radiolucencies that do not resolve after initial endodontic treatment (good quality), an extraction should be considered Periodontal Considerations when 10 mm of bone is all that remains from the mandibular canal to the remaining bone around the periodontally involved teeth, consideration is given to the predictable aspects of periodontal therapy. When in doubt, the teeth should often be extracted Periodontal Considerations Mandibular molar root resection should be replaced by extraction and implant therapy. The natural molar tooth that requires endodontics, root amputation, post and core placement, and nevertheless a compromised root with a poor root surface area may be more predictable to extract and replace with implant 0-, 5-, or 10-Year Rule PROGNOSIS PROTOCOL >10 years Keep the tooth and restore as indicated. 5–10 years Independent implant restoration. If the natural tooth must be included with implants in the restoration, make it a “living pontic” by adding implants on each side and splint together. <5 years Extract the tooth and graft the site or consider an implant. Examples of <5 years Patients with a potential structural failure after restoration (as a result of caries or trauma) and who require endodontics, functional crown lengthening, posts and cores When the patient has an endodontic lesion of greater than 5 mm on a previously treated endodontic tooth (which appears within an acceptable technique) A tooth that has pain during function, despite radiographically successful endodontic therapy, may have a split root If hygiene is poor in patients with a grade II or III furca involvement in molars To extract teeth with a good prognosis (with or without the need for endodontic or periodontal treatment) is discouraged.15 Implants are not yet 100% predictable, and implants should not be substituted for natural teeth presenting a good or even a fair prognosis. Behavioral factors & habits Behavioral factors & habits Psychological evaluation (1937) Philosophical Exacting (critical) Indifferent Hysterical Skeptical House’s classification Psychologic Evaluation (House’s classification (1937)) Philosophical patient: well motivated, cooperative, calm & composed even in difficult cases. Exacting (critical): likes each step in detail, makes alternative treatment for dentist, makes severe demands.* Indifferent: not very interested in treatment, blames the dentist for any mishap, not follow instructions, been coerced to come by friend, relative….* Hysterical: easily excited, highly apprehensive, unrealistic expectations* Skeptical: bad results from previous treatment, doubtful, often have severely resorbed ridges and poor health, might have psychological disturbances from recent personal trajedy # Behavioral factors & habits Smoking (≥ 10 /day) Cessation protocol: stop one week before surgery and 8 weeks after (Bain & Moy) Oral Hygiene Evaluation of patient existing oral hygiene, evaluation of patient’s dexterity and desire to maintain/ improve hygiene References Chapter 12. Carl Misch; Contemporary Implant Dentistry, 3rd Edition Chapter 5; Edmond Bedrossian; Implant Treatment Planning for the Edentulous Patient, 2010