In recent years there has been a paradigm shift with regard to new concepts for dental implant therapy that has led to a focus on more immediate implant treatment protocols. And with the increase in implant restora- tions overall, unfortunately this can mean an increase in malpositioned implants, many of which are a result of iatro- genic errors due to incorrect diagnoses or lack of commu- nication between team members.
These errors can occur when the implant is not guided by the tooth, the surgeon is not fully informed about the 3D design of the final restora- tion, the occlusal plane is not well established, or a surgical guide is not used to indicate the direction and ideal axial position of the implant.1 These deficiencies can result in complications—the most frequent being inadequate vol- ume of peri-implant tissue, recession that exposes the abutment-implant connection, incorrect positioning of the implant, or the lack of interdental papillae. If these principles are not respected, the results may be disappointing, or the entire treatment may be compromised, making it im- possible to produce the final prosthesis.
To address shortcomings in the treatment plan or errors in technique, alternative measures can be taken to aid in producing an esthetic and functional restoration. These in- clude angled abutments and/or artificial gingiva, crown lengthening, and secondary grafts.2 In extremely compro- mised cases, there is the option of surgically extracting the implant. However, surgical removal of a malpositioned im- plant can often result in large bony defects and soft tissue problems that subsequently require reconstructive sur- gery.3 Therefore, the planning of such treatment in the an- terior maxilla is highly sensitive between the surgical and the prosthetic phases, with the ultimate objective being to achieve a long-term result for the dental patient.
The objective of this case presentation is to show the correction of an esthetic problem with a malpositioned implant, describing the surgical and prosthetic steps needed during the clinical and laboratory stages to reestablish peri-implant tissue health and acceptable esthetics in the transition zone between the tissue and the prosthesis.
CASE PRESENTATION
A 21-year-old female was referred for prosthetic resolu- tion of a malpositioned implant in the maxillary right lateral incisor position (Figs 1a to 1f). Although the height of the interdental papilla was almost ideal, the implant had an ex- cessive buccal angle and there was a Seibert Class III4 residual defect and soft tissue fenestration with the graft- ed biomaterial visible. The cone beam computed tomogra- phy (CBCT) scan showed that the implant was in the sinus floor without an intact membrane (Fig 2).
Treatment Plan
A preliminary multidisciplinary plan was proposed to the patient due to the complexity of the situation, with the ob- jective to improve the prosthetic and peri-implant condi- tions and to optimize the appearance of the gingiva:
1. Removal of the implant with guided bone regeneration, with rotation of the pedicle during the same surgical procedure to increase the quantity and quality of the keratinized gingiva in the buccal cavity5
2. Diagnostic wax-up to make a surgical guide and provi- sional Maryland bridge
3. Replacement of the implant and placement of a con- nective tissue graft from the palate, stabilized in the custom healing abutment using the Slim Concept tech- nique6
4. After 4 months of healing: implant loading and pros- thetic management of the tissue
5. After 3 months: gingivectomy, final impression, and shade matching
6. Laboratory steps
7. Delivery of definitive implant restoration
Phase 1
Silicone impressions were taken in order to make a provi- sional Maryland bridge. The implant was removed and the epithelial flap rotated with extension of a connective tissue pedicle flap from the palate toward the buccal aspect. This increased the quality and quantity of soft tissue, closed the fenestration, and reduced the possibility of membrane exposure in its most critical phase, during wound healing. The first step was to carry out an initial gingival mapping to determine the length of the connective tissue graft and the position of the vertical incisions (Figs 3a to 3c). Two parallel vertical releasing incisions were made divergent to the total thickness from the ridge to the palate, outlining the pedicle and conserving the papillae on both sides of the defect as much as possible (Fig 4a). The length of the inci- sions depends on the length of the connective tissue re- quired. The two vertical incisions were joined with a horizontal partial-thickness incision along the ridge that would be the starting point for the division of the palatal tissue. Once the tissue was divided (Fig 4b), the incisions were corrected along the pedicle connective tissue, up to the bone (Fig 4c). These were defined laterally by the two vertical incisions made originally and apically in the base of the flap by another horizontal incision. The connective tis- sue pedicle was released gradually in an apicocoronal di- rection, maintaining the union and vascularity of the tissue (Fig 4d). Finally, the released internal part was unfolded, creating a pouch between the buccal mucosa and the al- veolar ridge (Fig 4e) to be sutured (Fig 4f).
The removal of the implant was carried out with the Nobel Retrieval Kit (Nobel Biocare USA). Bovine bone mineral matrix (Bio-Oss) and a titanium membrane (Neo- biotech) were used to regenerate the area (Fig 5). After 10 days of healing (Figs 6a to 6c), the formation of keratinized tissue was observed along with fenestration closure and an improvement in the tissue color. At 8 months, after wound healing was checked, it was confirmed that addi- tional procedures would be required to improve the white tissue defect still present (Figs 7a to 7c). CBCT was used to evaluate bone healing around the implant (Fig 8).
Phase 2
A traditional wax-up was done to guide the implant posi- tioning, using the contralateral tooth as a reference. To create an optimum emergence profile, it is of utmost im- portance to determine the apicocoronal position of the implant neck, which is placed approximately 3 mm apical to the final restorative buccal gingival margin.7 The wax was duplicated in acrylic to obtain a surgical guide and a provi- sional Maryland bridge to use during the surgical phases, including the placement and loading of the implant (Figs 9a to 9e).
Phase 3
Intrasulcular incisions were made in the neighboring teeth, obtaining a conservative flap with an inverted V incision in the center of the ridge in order to create papillae (Figs 10 and 11). An acrylic guide from the diagnostic wax-up was used for the apicocoronal and buccolingual references (Figs 12a and 12b). The implant (Bone Level, 3.3 mm × 10 mm, Straumann) was placed but not immediately load- ed. In the authors’ experience, if the flap and the papillae in healing ridges are not brought to their original position, there is a high risk of necrosis. If implants in healing ridges are immediately loaded, the outline of the new provisional can stop the tissue from being placed in its initial position. It was decided that a customized healing abutment would be used to allow the papillae to be brought to their ideal position and prematurely start the soft tissue profile man- agement (Figs 13a to 13d). This customized healing abutment will improve the residual 3D defect, giving support to the graft to create greater tissue volume horizontally (buc- cally and palatally) and vertically in the restoration interface and peri-implant tissue.
The connective tissue graft was obtained from the pal- ate and carefully de-epithelialized. A small perforation was made with a scalpel in the center of the graft to create access for the component through the graft, with the customized abutment screwed to the implant (Figs 14a and 14b). The graft measured approximately 12 mm × 8 mm, which was sufficient to compensate for the lost volume in the implant site. Simple suturing (Ethicon 5-0) was done in the papillae, placing them in the initial position to allow vascularization to take place in the grafted area to mini- mize the risk of necrosis (Figs 15a to 15e).
Phase 4
Four months after the implant was placed, CBCT verified the correct implant positioning and tissue maturation (Fig 16a). The handling of the peri-implant tissue during the provisional phase plays a crucial role in the treatment re- sult (Figs 16b and 16c). In 2010, Su et al8 defined the criti- cal and subcritical areas of the abutment and the contour of the crown, which is surrounded by soft tissue and shows the emergence profile. In 2013, Wittneben et al described the dynamic compression technique for the manipulation of peri-implant architecture (Fig 17). These techniques have several objectives: to establish an adequate emergence profile; to recreate balanced mucosa in harmony with the gingiva of the adjacent teeth; and to allow the gingival mar- gin, papillae, and position of the height/width of the zenith to be manipulated. The concepts of cervical contours are key to creating a correct emergence profile—a profile that comes from the dimensions of the tooth’s natural root.
The support and design of the soft tissue should be specific to each situation. A divergent profile is used when there are no large modifications to the tissue; a concave profile is used when the tissue needs to migrate in a coro- nal direction (an adjustment in the critical and subcritical zones can be carried out); and a convex profile is used to support the tissue at the level of the subcritical contour. The convex profile must be applied with great care to avoid facial overcontouring outside the physiological tolerance range. This profile may induce gingival edema, or ultimately, prosthetic gingival recession may occur. All of these profiles are directly related to the phenotype of each case, with the minimal required thickness to establish the bio- logic width and a minimal marginal bone loss over time being 2 mm (Figs 18a to 18c).
The implant loading was carried out after 16 weeks of tissue healing using the provisional Maryland bridge for correct incisal positioning. After the initial impression, the cervical contour of the provisional was adjusted, giving it a concave profile in the subcritical area so that the peri- implant tissue would migrate in a coronal direction. These adjustments were used to achieve stability of the gingival margins (Figs 19a to 19g).
Phase 5
Two months later, the gingival zenith was analyzed. A new adjustment was made to the cervical contour of the provisional (Figs 20a to 20d) and a gingivectomy was scheduled to level the margins. The patient returned for her final evaluation and to continue treatment (Figs 21a to 21c). The final impression was taken with a custom impression coping (Figs 22 and 23). It is the most accurate way to transfer the subgingival contour of the provisional and prevent tissue collapse during the impression. This allows the design of the provisional to be copied exactly and therefore an ideal biologic prosthesis to be obtained (Figs 24a to 24f). The shade was determined using the VITA Shade Guide (VITA USA) and gingival resins (Zirkonzahn) to ensure correct communication of the hard and soft tis- sues to the laboratory technician (Figs 25a to 25d).
Phase 6
Replacing a dental implant requires a complex process for obtaining an esthetically balanced result, especially in terms of efficiency between the dental and gingival morphology. A plaster cast was made using rigid stone and silicone for the gingival area. A titanium base was used to connect the implant and abutment (Fig 26). This hybrid restoration of- fers good mechanical resistance, allowing the creation of a favorable substrate layer from an optical point of view (Figs 27a and 27b). According to Jung et al, a broad titanium base can be an esthetic risk factor, as a gray shadow may be visible around the gingival margin. In their study, titanium induced the most prominent color change, while zirconia did not induce visible color changes in 2- and 3-mm-thick mucosa, regardless of whether it was ve- neered. However, with a mucosa thickness of 3 mm, no change in color on any specimen could be distinguished by the human eye.
The ceramist designed a zirconia hybrid abutment (e.max ZirCAD, Ivoclar Vivadent), imitating the emergence profile of the provisional. The abutment design should pro- vide excellent adaptation as well as biologic stability of the peri-implant tissue. After this provisional restoration was evaluated, the cervical regions were reduced to apply pink ceramic at the critical and subcritical contour levels, at- tempting to match the height of the gingival margin of the contralateral tooth. The hybrid restoration was first made in wax and then designed in zirconia using the Dental Wings CAD/CAM software (Figs 28a to 28d). The definitive restoration was then fabricated using a porcelain (e.max Ceram, Ivoclar Vivadent) layering ceramic (Figs 29a to 29c).
Phase 7
After the color of the restoration was finalized, the position of the hybrid restoration was confirmed and the cementation process initiated. The titanium base and intaglio resto- ration were prepared. The titanium base was sandblasted with 27-µm silica-modified aluminum oxide with 2.8 bars of pressure. After the surface was cleaned with phosphor- ic acid, the specimens were placed in alcohol in an ultra- sonic bath for 5 minutes. Once the surfaces were dried, a thin coat of silane was applied and heated in order to elim- inate the solvent and stabilize the covalent siloxane bond14 (Figs 30a to 30f). The internal surface of the restoration that was to be air braided was marked with a pencil, and the implant restoration emergence profile was coated with glycerin gel. The internal surface was sandblasted with 27-µm silica-modified aluminum oxide with 2.8 bars of pressure, at a distance of 10 mm, for approximately 20 seconds for a 10-mm area until pencil marks vanished. The restoration was then placed in alcohol in an ultrasonic bath for 5 minutes.15 Cementation of the restoration with glass-ionomer luting cement (FujiCEM 2, GC) was carried out extraorally (Figs 31 and 32). After the implant restora- tion was disinfected16 in situ with Bexident chlorhexidine gel (Siegfried), it was tightened with a final torque of 35 Ncm and the screw-access hole of the abutment sealed with polytetrafluoroethylene tape and composite resin. The seating was confirmed by radiograph. The crown adjust- ment and color were verified. The subcontour adjustments created in the crown for migration of the gingival tissue in this area were observed.
At the 1-month follow-up examination, the restoration had a natural appearance, with excellent biologic and opti- cal integration. The patient was very happy with the es- thetic outcome (Figs 33 and 34) and at 17 months showed good follow-up success (Figs 35 and 36).
CONCLUSION
This case emphasizes the importance of a correct diagno-sis and integral esthetic analysis before treatment is ini- tiated. The periodontal and peri-implant reconstructive procedures carried out during the surgical and prosthetic phases shown in this article have a positive impact on the gingival level and volume, which is directly associated with the final subgingival contour of the ceramic restoration and a favorable esthetic result of the hard and soft tissues.
To address shortcomings in the treatment plan or errors in technique, alternative measures can be taken to aid in producing an esthetic and functional restoration. These in- clude angled abutments and/or artificial gingiva, crown lengthening, and secondary grafts.2 In extremely compro- mised cases, there is the option of surgically extracting the implant. However, surgical removal of a malpositioned im- plant can often result in large bony defects and soft tissue problems that subsequently require reconstructive sur- gery.3 Therefore, the planning of such treatment in the an- terior maxilla is highly sensitive between the surgical and the prosthetic phases, with the ultimate objective being to achieve a long-term result for the dental patient.
The objective of this case presentation is to show the correction of an esthetic problem with a malpositioned implant, describing the surgical and prosthetic steps needed during the clinical and laboratory stages to reestablish peri-implant tissue health and acceptable esthetics in the transition zone between the tissue and the prosthesis.
CASE PRESENTATION
A 21-year-old female was referred for prosthetic resolu- tion of a malpositioned implant in the maxillary right lateral incisor position (Figs 1a to 1f). Although the height of the interdental papilla was almost ideal, the implant had an ex- cessive buccal angle and there was a Seibert Class III4 residual defect and soft tissue fenestration with the graft- ed biomaterial visible. The cone beam computed tomogra- phy (CBCT) scan showed that the implant was in the sinus floor without an intact membrane (Fig 2).
Treatment Plan
A preliminary multidisciplinary plan was proposed to the patient due to the complexity of the situation, with the ob- jective to improve the prosthetic and peri-implant condi- tions and to optimize the appearance of the gingiva:
1. Removal of the implant with guided bone regeneration, with rotation of the pedicle during the same surgical procedure to increase the quantity and quality of the keratinized gingiva in the buccal cavity5
2. Diagnostic wax-up to make a surgical guide and provi- sional Maryland bridge
3. Replacement of the implant and placement of a con- nective tissue graft from the palate, stabilized in the custom healing abutment using the Slim Concept tech- nique6
4. After 4 months of healing: implant loading and pros- thetic management of the tissue
5. After 3 months: gingivectomy, final impression, and shade matching
6. Laboratory steps
7. Delivery of definitive implant restoration
Phase 1
Silicone impressions were taken in order to make a provi- sional Maryland bridge. The implant was removed and the epithelial flap rotated with extension of a connective tissue pedicle flap from the palate toward the buccal aspect. This increased the quality and quantity of soft tissue, closed the fenestration, and reduced the possibility of membrane exposure in its most critical phase, during wound healing. The first step was to carry out an initial gingival mapping to determine the length of the connective tissue graft and the position of the vertical incisions (Figs 3a to 3c). Two parallel vertical releasing incisions were made divergent to the total thickness from the ridge to the palate, outlining the pedicle and conserving the papillae on both sides of the defect as much as possible (Fig 4a). The length of the inci- sions depends on the length of the connective tissue re- quired. The two vertical incisions were joined with a horizontal partial-thickness incision along the ridge that would be the starting point for the division of the palatal tissue. Once the tissue was divided (Fig 4b), the incisions were corrected along the pedicle connective tissue, up to the bone (Fig 4c). These were defined laterally by the two vertical incisions made originally and apically in the base of the flap by another horizontal incision. The connective tis- sue pedicle was released gradually in an apicocoronal di- rection, maintaining the union and vascularity of the tissue (Fig 4d). Finally, the released internal part was unfolded, creating a pouch between the buccal mucosa and the al- veolar ridge (Fig 4e) to be sutured (Fig 4f).
The removal of the implant was carried out with the Nobel Retrieval Kit (Nobel Biocare USA). Bovine bone mineral matrix (Bio-Oss) and a titanium membrane (Neo- biotech) were used to regenerate the area (Fig 5). After 10 days of healing (Figs 6a to 6c), the formation of keratinized tissue was observed along with fenestration closure and an improvement in the tissue color. At 8 months, after wound healing was checked, it was confirmed that addi- tional procedures would be required to improve the white tissue defect still present (Figs 7a to 7c). CBCT was used to evaluate bone healing around the implant (Fig 8).
Phase 2
A traditional wax-up was done to guide the implant posi- tioning, using the contralateral tooth as a reference. To create an optimum emergence profile, it is of utmost im- portance to determine the apicocoronal position of the implant neck, which is placed approximately 3 mm apical to the final restorative buccal gingival margin.7 The wax was duplicated in acrylic to obtain a surgical guide and a provi- sional Maryland bridge to use during the surgical phases, including the placement and loading of the implant (Figs 9a to 9e).
Phase 3
Intrasulcular incisions were made in the neighboring teeth, obtaining a conservative flap with an inverted V incision in the center of the ridge in order to create papillae (Figs 10 and 11). An acrylic guide from the diagnostic wax-up was used for the apicocoronal and buccolingual references (Figs 12a and 12b). The implant (Bone Level, 3.3 mm × 10 mm, Straumann) was placed but not immediately load- ed. In the authors’ experience, if the flap and the papillae in healing ridges are not brought to their original position, there is a high risk of necrosis. If implants in healing ridges are immediately loaded, the outline of the new provisional can stop the tissue from being placed in its initial position. It was decided that a customized healing abutment would be used to allow the papillae to be brought to their ideal position and prematurely start the soft tissue profile man- agement (Figs 13a to 13d). This customized healing abutment will improve the residual 3D defect, giving support to the graft to create greater tissue volume horizontally (buc- cally and palatally) and vertically in the restoration interface and peri-implant tissue.
The connective tissue graft was obtained from the pal- ate and carefully de-epithelialized. A small perforation was made with a scalpel in the center of the graft to create access for the component through the graft, with the customized abutment screwed to the implant (Figs 14a and 14b). The graft measured approximately 12 mm × 8 mm, which was sufficient to compensate for the lost volume in the implant site. Simple suturing (Ethicon 5-0) was done in the papillae, placing them in the initial position to allow vascularization to take place in the grafted area to mini- mize the risk of necrosis (Figs 15a to 15e).
Phase 4
Four months after the implant was placed, CBCT verified the correct implant positioning and tissue maturation (Fig 16a). The handling of the peri-implant tissue during the provisional phase plays a crucial role in the treatment re- sult (Figs 16b and 16c). In 2010, Su et al8 defined the criti- cal and subcritical areas of the abutment and the contour of the crown, which is surrounded by soft tissue and shows the emergence profile. In 2013, Wittneben et al described the dynamic compression technique for the manipulation of peri-implant architecture (Fig 17). These techniques have several objectives: to establish an adequate emergence profile; to recreate balanced mucosa in harmony with the gingiva of the adjacent teeth; and to allow the gingival mar- gin, papillae, and position of the height/width of the zenith to be manipulated. The concepts of cervical contours are key to creating a correct emergence profile—a profile that comes from the dimensions of the tooth’s natural root.
The support and design of the soft tissue should be specific to each situation. A divergent profile is used when there are no large modifications to the tissue; a concave profile is used when the tissue needs to migrate in a coro- nal direction (an adjustment in the critical and subcritical zones can be carried out); and a convex profile is used to support the tissue at the level of the subcritical contour. The convex profile must be applied with great care to avoid facial overcontouring outside the physiological tolerance range. This profile may induce gingival edema, or ultimately, prosthetic gingival recession may occur. All of these profiles are directly related to the phenotype of each case, with the minimal required thickness to establish the bio- logic width and a minimal marginal bone loss over time being 2 mm (Figs 18a to 18c).
The implant loading was carried out after 16 weeks of tissue healing using the provisional Maryland bridge for correct incisal positioning. After the initial impression, the cervical contour of the provisional was adjusted, giving it a concave profile in the subcritical area so that the peri- implant tissue would migrate in a coronal direction. These adjustments were used to achieve stability of the gingival margins (Figs 19a to 19g).
Phase 5
Two months later, the gingival zenith was analyzed. A new adjustment was made to the cervical contour of the provisional (Figs 20a to 20d) and a gingivectomy was scheduled to level the margins. The patient returned for her final evaluation and to continue treatment (Figs 21a to 21c). The final impression was taken with a custom impression coping (Figs 22 and 23). It is the most accurate way to transfer the subgingival contour of the provisional and prevent tissue collapse during the impression. This allows the design of the provisional to be copied exactly and therefore an ideal biologic prosthesis to be obtained (Figs 24a to 24f). The shade was determined using the VITA Shade Guide (VITA USA) and gingival resins (Zirkonzahn) to ensure correct communication of the hard and soft tis- sues to the laboratory technician (Figs 25a to 25d).
Phase 6
Replacing a dental implant requires a complex process for obtaining an esthetically balanced result, especially in terms of efficiency between the dental and gingival morphology. A plaster cast was made using rigid stone and silicone for the gingival area. A titanium base was used to connect the implant and abutment (Fig 26). This hybrid restoration of- fers good mechanical resistance, allowing the creation of a favorable substrate layer from an optical point of view (Figs 27a and 27b). According to Jung et al, a broad titanium base can be an esthetic risk factor, as a gray shadow may be visible around the gingival margin. In their study, titanium induced the most prominent color change, while zirconia did not induce visible color changes in 2- and 3-mm-thick mucosa, regardless of whether it was ve- neered. However, with a mucosa thickness of 3 mm, no change in color on any specimen could be distinguished by the human eye.
The ceramist designed a zirconia hybrid abutment (e.max ZirCAD, Ivoclar Vivadent), imitating the emergence profile of the provisional. The abutment design should pro- vide excellent adaptation as well as biologic stability of the peri-implant tissue. After this provisional restoration was evaluated, the cervical regions were reduced to apply pink ceramic at the critical and subcritical contour levels, at- tempting to match the height of the gingival margin of the contralateral tooth. The hybrid restoration was first made in wax and then designed in zirconia using the Dental Wings CAD/CAM software (Figs 28a to 28d). The definitive restoration was then fabricated using a porcelain (e.max Ceram, Ivoclar Vivadent) layering ceramic (Figs 29a to 29c).
Phase 7
After the color of the restoration was finalized, the position of the hybrid restoration was confirmed and the cementation process initiated. The titanium base and intaglio resto- ration were prepared. The titanium base was sandblasted with 27-µm silica-modified aluminum oxide with 2.8 bars of pressure. After the surface was cleaned with phosphor- ic acid, the specimens were placed in alcohol in an ultra- sonic bath for 5 minutes. Once the surfaces were dried, a thin coat of silane was applied and heated in order to elim- inate the solvent and stabilize the covalent siloxane bond14 (Figs 30a to 30f). The internal surface of the restoration that was to be air braided was marked with a pencil, and the implant restoration emergence profile was coated with glycerin gel. The internal surface was sandblasted with 27-µm silica-modified aluminum oxide with 2.8 bars of pressure, at a distance of 10 mm, for approximately 20 seconds for a 10-mm area until pencil marks vanished. The restoration was then placed in alcohol in an ultrasonic bath for 5 minutes.15 Cementation of the restoration with glass-ionomer luting cement (FujiCEM 2, GC) was carried out extraorally (Figs 31 and 32). After the implant restora- tion was disinfected16 in situ with Bexident chlorhexidine gel (Siegfried), it was tightened with a final torque of 35 Ncm and the screw-access hole of the abutment sealed with polytetrafluoroethylene tape and composite resin. The seating was confirmed by radiograph. The crown adjust- ment and color were verified. The subcontour adjustments created in the crown for migration of the gingival tissue in this area were observed.
At the 1-month follow-up examination, the restoration had a natural appearance, with excellent biologic and opti- cal integration. The patient was very happy with the es- thetic outcome (Figs 33 and 34) and at 17 months showed good follow-up success (Figs 35 and 36).
CONCLUSION
This case emphasizes the importance of a correct diagno-sis and integral esthetic analysis before treatment is ini- tiated. The periodontal and peri-implant reconstructive procedures carried out during the surgical and prosthetic phases shown in this article have a positive impact on the gingival level and volume, which is directly associated with the final subgingival contour of the ceramic restoration and a favorable esthetic result of the hard and soft tissues.
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