anterior single implant supported restoration in esthetic zone.ppt

Anterior single implantsupported restoration in esthetic zone Maxillary Anterior Single-Tooth Replacement Misch, Chapter 22, Pages 368-410

Dr. Mohammed Alshehri

BDS, AEGD, SSC-ARD

Therapeutic modalities for tooth replacement in the esthetic zone • Conventional fixed partial dentures (FPDs), comprising cantilever units • Resin-bonded ("adhesive") bridges • Conventional removable partial dentures (RPDs)

• Tooth-supported overdentures • Orthodontic therapy (closure of edentulous spaces) • Implant-supported prostheses (fixed, retrievable or removable suprastructures)

Single implant-supported restoration • Maxillary central incisor single-tooth replacement is often the most difficult procedure in all of implant dentistry. • The highly esthetic zone of the premaxilla often requires both hard (bone and teeth) and soft tissue restoration. • single-tooth implant has the highest success rate compared with any other treatment option to replace missing teeth with an implant restoration

Fundamental objective esthetic criteria (Magne & Belser 2002) 1. Gingival health 2. Interdental closure 3. Tooth axis 4. Zenith of the gingival contour 5. Balance of the gingival levels 6. Level of the interdental contact 7. Relative tooth dimensions 8. Basic features of tooth form 9. Tooth characterization 10. Surface texture 11. Color 12. Incisal edge configuration 13. Lower lip line 14. Smile symmetry • Subjective criteria (esthetic integration) • Variations in tooth form • Tooth arrangement and positioning • Relative crown length • Negative space • dentures

Challenging esthetics Bone height • Midcrest position of the edentulous site should be 2 mm below the facial CEJ of the adjacent teeth. • The interproximal bone should be scalloped 3 mm more incisal than the midcrest position. • Becker et al. 1997 classified the rang of interpmximal bone height above the midfacial scallop from less than 2.1 mm (flat) to scalloped 2.8 mm to pronounced scalloped < 4.1 mm. flat anatomy square-shaped tooth scalloped ovoid-shaped tooth

Under perfect conditions, the implant body should not be inserted until the bone and soft tissue are within normal limits.

Challenging esthetics Mesiodistal •space Two-piece implant

should be at least 1.5 mm from

an adjacent tooth. • When the implant is closer than this to an adjacent tooth bone loss related to the microgap, biological width violation , and/or stress. • one-piece implant should be at least 1 mm from an adjacent tooth. “microgap eliminated and the vertical defect is narrower than most two-piece implant systems so they can be placed closer”

Challenging esthetics Faciopalatal Width • A 25% decrease in faciopalatal width occurs within the first year of tooth loss and rapidly evolves into a 30% to 40% decrease within 3 years. • The bone width loss is primarily from the facial region, because the labial plate is very thin compared with the palatal plate, and facial undercuts are often found over the roots of the teeth.

Challenging esthetics Implant size • first factor that influences the size of an implant is the mesiodistal dimension of the missing tooth. ”2 mm below CEJ” • The second factor that determines the mesiodistal implant diameter is the necessary distance from an adjacent tooth root. ”due to this the implant is usually smaller in diameter than natural tooth”

Challenging esthetics Implant size • Distance between an adjacent teeth roots in comparison with implants distance. 0.5 – 1.5

2 mm

3 mm

4 mm

Challenging esthetics Implant size • The width of bone should allow at least 1.5mm on the facial aspect of the implant. • The faciopalatal width dimension is not as critical on the palatal aspect of the implant, because it is dense cortical bone, more resistant to bone loss, and not within the esthetic zone. • Facial bone grafting at the time of implant insertion is frequently needed, because the bone volume in width is often compromised.

Implant body position Mesiodistal position • The best implant position is under the incisal edge of the final crown, or slightly more palatal (A). The ideal mesiodistal implant position for a central incisor is 0.5 to 1.0 mm more distal than the midtooth position. This decreases the risk of encroachment on the incisive canal (B). The best mesiodistal position for a cuspid is centered in the cuspid position.

(A)

(B)

Implant body position Mesiodistal position • When the central incisor implant is placed, the implant may encroach on the canal and result in a probing pocket depth of 10 mm or greater on the mesiopalatal surface of the implant. • On occasion, the contents of the foramen must be removed and a bone graft inserted, to decrease the size of the incisive canal.

Implant body position Faciopalatal position • The crestal bone should be at least 1.5 mm wider on the facial aspect of the implant and 0.5 mm on the palatal aspect. • The thickness of bone on the facial aspect of a natural root is usually 0.5 mm thick. As a result, the implant is1mm or more palatal than the facial emergence of the adjacent crowns at the free gingival margin.

Implant body position Implant angulation •

In the literature, three faciopalatal angulations of the implant body are suggested: (1) a facial angulation so that emergence of the final crown will be similar to adjacent teeth. (2) under the incisal edge of the final restoration. (3) within the cingulum position of the implant crown.

Miami 2007

Implant body position Implant angulation

•

A, a position below the incisal edge is best used for a cemented crown in the esthetic zone. B, an implant is in the position of the natural root of the tooth. Although this makes sense, it places the implant too facial, and an angled abutment is usually necessary, C, an implant in the cingulum position that is used when a screw-retained crown is the trea ment of choice. This position requires a facial ridge lap of porcelain when used for FP-l prostheses

Implant body position Facial Implant body angulation •

The facial implant position is predicated on the concept that the facial emergence of the implant crown at the cervical should be in the same position as a natural tooth.

•

The crown of a natural tooth has two planes, and its incisal edge is palatal to the facial emergence of the natural tooth by 12 to 15 degrees.

Implant body position Facial Implant body angulation •

Because the implant is narrower in diameter than the faciopalatal root dimension, when the implant body is oriented as a natural tooth and has a facial emergence, a straight abutment is not wide enough to permit the two or three plane reduction to bring the incisal edge of the preparation more palatal. As a result, the incisal edge of the preparation remains too facial. Therefore when the implant is angled to the facial emergence of a tooth, an angled abutment of 15 degrees must be used to bring the incisal edge more palatal.

Implant body position Facial Implant body angulation • •

•

Most two-piece angled abutments have a design flaw that compromises facial cervical esthetics. The metal flange facial to the abutment screw is thinner than a straight abutment and may result in fracture (especially because angled loads are placed on thefacial-positioned implant). No single method exists to restore proper esthetics when the implant abutment is located above the free gingival margin of the adjacent teeth. At best, the final crown appears too long and too facial. Soft tissue grafts and/or bone augmentation do not improve the condition.

Implant body position Facial Implant body angulation •

•

The natural maxillary anterior teeth are loaded at a12- to I5 degree angle, because of their natural angulation in comparison with the mandibular anterior teeth. This is one reason the maxillary anterior teeth are wider in diameter than mandibular anterior teeth (which are loaded in their long axis). The facial angulation of the implant body often corresponds to an implant body angulation, which leads to I5 degrees off axial loads and increases the force to the abutment screwimplant-bone complex by 25.9%, compared with a long axis load.

Implant body position Facial Implant body angulation •

These offset loads increase the risks of abutment screw loosening, crestal bone loss, and cervical soft tissue marginal shrinkage. As a result, implants angled too facially compromise the esthetics and increase the risk of complications.

Implant body position Cingulum implant body angulation •

•

A second angulation suggested in the literature is more palatal, with an emergence under the cingulum of the crown. This position is often the goal when a screwretained crown is used in restoration. The prosthesis fixation screw (to retain a maxillary anterior crown) cannot be located in the incisal or facial region of the crown for obvious reasons.

Implant body position Cingulum implant body angulation •

•

This most often requires a facial projeaion of the crown or "buccal correction" facing away from the implant body. The facial ridge lap must extend 2 to 4 mm and is often similar in contour to the modified ridge lap pontic of three-unit fixed prosthesis. Although an acceptable esthetic restoration may be developed, especially with the additional cervical porcelain, the hygiene requirements and present implant dentistry standards render this approach unacceptable.

Implant body position Cingulum implant body angulation •

Some authors argue that an improved contour may be developed subgingivaUy with a palatal implant position. To create this contour, the implant body must be positioned more apical than desired. This position may prevent food from accumulating on the cervical "table" of the crown. However, the subgingival ridge lap does not permit access to the facial sulcus of the implant body for the elimination of plaque, as well as to evaluate the bleeding index or facial bone loss.

Implant body position Cingulum implant body angulation •

Greater interarch clearance is often needed with an implant palatal position, because the permucosal post exits the tissue in a more palatal position. Inadequate interarch space may especially hinder the restoration of Angle's Class II, division 2 patients, with the implant in this position. The bony ridge should be augmented if too narrow for the model implant diameter and position, or an alternate treatment option should be seleaed. The anterior single-tooth implant should use a cement-retained crown, so the cingulum screw position is not necessary.

Implant body position Ideal implant body angulation •

•

A straight line is determined by connecting two points. The clinician determines the line for the best angulation by the point of the incisal edge position of the implant crown and the midfaciopalatal position on the crest of the bone. The center of the implant is located directly under the incisal edge of the crown so that a straight abutment for cement retention emerges directly below the incisal edge. Because the crown profile is in two planes, with the incisal edge more palatal than the cervical portion, the incisal edge position is perfea for implant placement and also

Implant body position Ideal implant body angulation •

•

The facial emergence of the crown mimics the adjacent teeth, proceeding from the implant body under the tissue. The angle of force to the implant is also improved, which decreases the crestal stresses to the bone and abutment screws. It is easier to correct a slight palatal position in the final crown contour compared with the implant body angled too facial.

Implant body position Ideal implant body angulation •

•

The implant abutment selected for a maxillary anterior single-tooth implant is almost always for a cemented restoration. Single anterior crowns do not require readily retrievable restorations. In addition, a greater range of corrective options exists with a cement-retained crown for implants not well placed. The location of the cervical margin of a cemented crown can be anywhere on the abutment post or even on the body of the implant, provided it is 1 mm or more above the bone.

Implant body position Ideal implant body angulation •

The incisal edge of the template may be notched for the drills, because the best placement of the drill is directly through the incisal edge. However, most often the surgeon does not require a template, because the adjacent teeth provide a guide for a single-tooth implant. In addition, the integrity of facial cortical plate is more readily assessed during the surgery when a template is not used.

Miami 2007

Implant position “depth” Too Deep (> 4 mm)

•

•

The implant countersunked below the crestal bone more than 4 mm below the facial CEJ of the adjacent teeth to develop a crown emergence profile similar to a natural tooth. The bulk of subgingival porcelain provides good color and contour for the crown. However, several concerns arise regarding the long-term sulcular health around the implant.

Implant position “depth” Too Deep (> 4 mm)

•

•

The first year of function often corresponds to a mean bone loss range of 0.5 to 3.0 mm, dependent in part on implant design. Malevez et al.32 noted more pronounced bone loss for conical implants that had a long, smooth, tapered crest module. The bone is lost at least 0.5 mm below the abutment to implant body connection and extends to any smooth or machined surface beyond the crest module (depending on the implant design). This may lead to facial probing depths of 7 to 8

Implant position “depth” Too Deep (> 4 mm)

•

•

Grunder evaluated single-tooth implants in function for 1 year and noted the bone levels were 2 mm apical to the implantabutment connection and sulcular probing depths were 9.0 to 10.5 mm using a Branemark implant design. The attachment mechanism of the soft tissue above the bone is less tenacious compared with a tooth, and the defense mechanism of the peri-implant tissues may be weaker than that of teeth. The clinician, to err on the side of safety for the best sulcular health conditions, should

Implant position “depth” Too shallow (> 2 mm)

•

•

•

The implant body is positioned less than 2 mm below the facial free gingival margin of the crown, the cervical esthetics of the restoration are at an increased risk. The porcelain of the crown may not be subgingival enough to mask the titanium color of the abutment below the margin. Periodontal surgical procedures to position soft tissue over the titanium roots are unpredictable.

Implant position “depth” Too shallow (> 2 mm)

•

•

The crestal bone height is coronal to the perfect height. The two most common conditions that result in this finding are (1) when the adjacent teeth are closer than 6 mm (in agenesis of a lateral incisor) and (2) when a block bone graft regenerated width and height of bone. Ideally, the interproximal bone is 3 mm above the midcrestaI bone.

Implant position “depth” Too shallow (> 2 mm)

•

•

When a single-tooth implant replaces this missing tooth, an osteoplasy should be performed so that the midcrestal region is 3 mm apical to the free gingival margin of the future crown. The same conditions may occur when bone augmentation gains height to the interproximal height of bone. To solve the problem of an implant body placed too shallow, the restoring dentist may need to prepare the implant crest module and place the margin of the crown

Implant position “depth” Ideal depth (3 mm) •

This positions the platform of the implant 3 mm below the facial free gingival margin of the implant crown. In addition, it provides 3 mm of soft tissue for the emergence of the implant crown on the midfacial region and more as the soft tissue measurements proceed toward the interproximal. This depth also increases the thickness of the soft tissues over the titanium implant body, which masks the darker color above the bone. It should be noted that the free gingival margin of a lateral incisor is often 1 mm more incisal than the adjacent central and canine

Soft tissue incision different approaches to enhance the soft tissue appearance

Soft tissue incision Surgical additive techniques

• • • •

Pouch procedures. Interpositional grafts. Sliding flaps. connective tissue grafts (autogenous or acellular dennal matrix).

Soft tissue incision interproximal soft tissue in the implant site classified into three categories • The papillae have an acceptable height in the edentulous site. • The papillae have less than acceptable height. • One papilla is acceptable and the other papilla is depressed and requires elevation.

Soft tissue incision

Transitional prosthesis •

• •

Resin-bonded fixed restorations strongly suggested to be fabricated to provide improved speech and function, especially when crestal bone regeneration is performed and for extended healing time. Transitional cantilevered prosthesis from adjacent tooth requiring crown. When the patient requires orthodontics, a denture tooth and an attached bracket may be added to the orthodontic wire.

Transitional prosthesis •

A removable device may be used as short term for cosmetic emergencies. (1) An Essix appliance is an acrylic shell, similar to a bleaching tray, that has a denture tooth attached to replace the missing tooth. This device is the easiest for tooth replacement after surgical procedures. (2) A cast clasp RPD with indirect rest seats to prevent rotation movements on the surgical site. (3) Flipper.

Immediate implant insertion after extraction According to Kois, five diagnostic keys exist for predictable single-tooth peri-implant esthetics when an immediate extraction and implant insertion is contemplated: (1) the tooth position relative to the free gingival margin. (2) the form of the periodontium. (3) the biotype of the periodontium. (4) the tooth shape. (5) the position of the osseous crest before extraction.

Immediate implant insertion after extraction

Stage II uncovery and soft tissue A. Subtraction technique (canine soft tissue drape) •

When the soft tissue along the edentulous crest is at the level of the desired interdental papillae and is of sufficient quality and volume, a subtraction technique (e.g., gingivoplasty with a coarse diamond) sculpts the crestal gingival tissues to reproduce the cervical emergence contour of the crown, complete with interdental papillae and proper labial gingival contour. The contour of the mid facial position of the tissue is 1 mm more incisal than the contour of the adjacent teeth to allow for the gingival shrinkage commonly observed during the first year of implant loading. The interdental papilla zones are also made slightly larger than the final desired

Stage II uncovery and soft tissue B. Addition technique •

1. Split-finger approach

Stage II uncovery and soft tissue B. Addition technique •

1. Split-finger approach

Stage II uncovery and soft tissue B. Addition technique •

1. Split-finger approach

Stage II uncovery and soft tissue B. Addition technique •

1. Split-finger approach

Stage II uncovery and soft tissue B. Addition technique •

1. Split-finger approach

Stage II uncovery and soft tissue B. Addition technique •

1. Split-finger approach

Stage II uncovery and soft tissue B. Addition technique •

2. Crest elevated and PME “permucosal extention” added as "tent pole" for soft tissue

Summary •

The replacement of a single tooth in the premaxilla is challenging because of the highly specific soft and hard tissue criteria, in addition to all other esthetic, phonetic, functional and occlusal requirements. Anterior tooth loss usually compromises ideal bone volume and position for proper implant placement. Implant diameter, compared with that of natural teeth, results in challenging cervical esthetics.

Summary •

Unique surgical and prosthetic concepts are implemented for proper results. In spite of all the technical difficulties that the restoring dentist may face, the anterior single-tooth implant is the modality of choice to replace a missing anterior maxillary tooth.

Anterior single implantsupported restoration in esthetic zone Implants In The Esthetic Zone Lindhe V 2 , Chapter 53, Pages 1146-1166

Patient expectations related to maxillary anterior edentulous segments • Long-lasting esthetic and functional result with a high degree of predictability • Minimal invasiveness (preservation of tooth structure) • Maximum subjective comfort • Minimum risk for complications associated with surgery and healing phase • Avoidance of removable prostheses • Optimum cost effectiveness

Therapeutic modalities for tooth replacement in the esthetic zone •

Conventional fixed partial dentures (FPDs), comprising cantilever units • Resin-bonded ("adhesive") bridges • Conventional removable partial dentures (RPDs) • Tooth-supported overdentures • Orthodontic therapy (closure of edentulous spaces) • Implant-supported prostheses (fixed, retrievable or removable suprastructures) • Combinations of the above

Criteria favoring implant-borne restorations • Normal wound healing capacity • Intact neighboring teeth • Unfavorable ("compromised") potential abutment teeth • Extended edentulous segments • Missing strategic abutment teeth • Presence of diastemas

Evaluation of anterior tooth-bound edentulous sites prior to implant therapy • Mesio-distal dimension of the edentulous segment, including its comparison with existing contralateral control teeth • Three-dimensional analysis of the edentulous segment regarding soft tissue configuration and underlying alveolar bone crest (ref. "bone-mapping")

Evaluation of anterior tooth-bound edentulous sites prior to implant therapy • Neighboring teeth: • volume (relative tooth dimensions), basic features of tooth form and three-dimensional position and orientation of the clinical crowns • structural integrity and condition • surrounding gingival tissues (course/scalloping of the gingival line) • periodontal and endodontic status/conditions • crown-to-root ratio • length of roots and respective inclinations in the frontal plane • eventual presence of diastemata

Evaluation of anterior tooth-bound edentulous sites prior to implant therapy • Interarch relationships: • vertical dimension of occlusion • anterior guidance • interocclusal space • Esthetic parameters: • height of upper smile line ("high lip" versus "low lip") • lower lip line • course of the gingival-mucosa line • orientation of the occlusal plane • dental versus facial symmetry • lip support

Optimal three-dimensional implant positioning ("restoration-driven implant placement") in anterior maxillary sites. Implant = apical extension of the ideal future restoration

• Correct vertical position of implant shoulder (sink depth) using the cemento-enamel junction of adjacent teeth as reference: • no visible metal • gradually developed, flat axial profile • Correct oro-facial position of point of emergence for future

Optimal three-dimensional implant positioning ("restoration-driven implant placement") in anterior maxillary sites. Implant = apical extension of the ideal future restoration

suprastructure from the mucosa: • similar to adjacent teeth • flat emergence profile •Implant axis compatible with available prosthetic treatment options (ideally: implant axis identical with "prosthetic axis")

Basic considerations related to anterior single-tooth replacement Achievements Predictable and reproducible results regarding both esthetic parameters and longevity in sites without significant vertical tissue deficienies Well defined and well established surgical protocols: • restoration-driven implant placement Adequate and versatile restorative protocols and prosthetic components: • occlusal/transverse screw-retention • angulated abutments • high-strength ceramic components

Basic considerations related to anterior single-tooth replacement Sites with buccal bone deficienie Lateral bone augmentation using autografts and barrier membranes: • technique offers efficacy and predictability • simultaneous or staged approach depending on defect extension and defect morphology Lateral bone augmentation by means of alveolar bone crest splitting and/or various osteotome techniques: • limited clinical long-term documentation

Basic considerations related to anterior single-tooth replacement Limitations Combined vertical bone and soft tissue deficienies: • following removal of ankylosed teeth or failing implants • advanced loss of periodontal tissues, including gingival recession, on neighboring teeth • limited scientific documentation related to vertical bone augmentation and distraction

Basic considerations related to multiple-unit implant restorations in sites with horizontal and/or vertical soft and hard tissue deficiencies

Achievements Predictable and reproducible results regarding lateral bone augmentation using barrier membranes supported by autografts : • allows implant placement in patients with a low lip line.

Basic considerations related to multiple-unit implant restorations in sites with horizontal and/or vertical soft and hard tissue deficiencies

Limitations Vertical bone augmentation is difficult to achieve and related surgical techniques lack prospective clinical long-term documentation Interimplant papillae cannot predictably be reestablished as of yet

Conclusion In conclusion, the concepts and therapeutic modalities do exist nowadays to solve – by means of implants - elegantly as well as predictably a majority of clinical situations requiring the replacement of missing teeth in the esthetic zone, and the most promising novel approaches and perspectives can already be identified on a not too distant horizon.