Biologic shaping is an option to the traditional method of crown lengthening which is performed when invasion of the junctional and/or connective tissue attachment associated with a tooth has occurred. Biologic shaping involves reshaping the existing tooth surface in combination with conservative removal of the supporting alveolar bone to create the width needed for the dental restoration to be biologically acceptable.
Biologic shaping accomplishes several goals: (1) Minimum supporting bone is removed; (2) Deleterious root surface anatomy, such as grooves, concavities, and cementoenamel projections, can be diminished or removed completely; (3) A smooth root surface that is more biologically acceptable to soft tissue is created; (4) Class I and II furcation lesions (mild to moderately-advanced bone loss between the roots of molar teeth) may be decreased or eliminated improving the long-term prognosis of these compromised teeth; and (5) improved gingival contours and space for restorative materials can be created in situations where close root proximity between teeth is present. This technique aims to optimize the periodontal health of a tooth to receive a crown and maximize the long-term outcome of the dental restoration for the patient. Scroll down to view two cases where this technique was utilized to enhance the restorative doctor's outcome in providing a predictable, periodontally healthy, and optimal result long-term for the patient.
Click here to view the following peer reviewed article on the procedure of biologic shaping: Melker DJ, Richardson CR. Root reshaping: An integral component to periodontal surgery. Int J Perio Rest Dent 2001; 21:297-301.
Case 1
Pre Operative view of teeth planned for crowns. The temporary crowns (i.e. provisionals) have been removed. Probing depth appears within normal limits upon first glance.
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Tissue reflected away demonstrates that crown margin would be proximate to the furcation entrance of teeth #18 & #19. If crowns were placed without this surgical procedure, long-term prognosis of teeth would be compromised as bone loss is likely to ensue because a permanent crown would not allow for a properly contoured environment from the level of the bone transitioning up to the new prosthesis. Limited space between the bone and crown margin is noted for tooth #20. Tartar formation is also noted at the mesial of #19.
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Reshaped teeth and newly recontoured bone environment (below) to allow for more optimal and predictable long-term prognoses. Tartar has been removed from the mesial of #19 and the furcation environment has been eliminated in prepartion for the new crowns. The more white appearing tooth structure represents bonded cores which have been placed into the teeth by the restorative dentist pre surgically. These cores build back lost structure compromised by decay and increase the overall strength of the individual teeth.
This approach has also protected the bone environment by mainly reshaping the teeth and simply recontouring the bone to adapt to the reshaped tooth environment, not resecting the bone as performed in conventional crown lenghtening procedures.
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Gum tissue is sutured with microsurgical dissolving sutures and temporary crowns are replaced. A healing period of 1 month will elapse at which time the patients dentist will reline the temporary crowns to the level of the healig gum tissue. This ensures temporary crowns have excellent fitting margins which remain just above the healing tissue so as not to impinge on it.
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After a healing and tissue maturation period of 3 months, the dentist creates the final tooth preparations on the reshaped tooth, following the pattern that has been created at the surgery. Final impressions are then made for the laboratory. Final all porcelain crowns are shown below which mimic the newly reshaped environment for each tooth. Note flat contours of molar furcations and margin placement which is at, not within, the healed gum tissue. Lack of inflammation is noted and optimal periodontal-restorative health created for the patient.
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Case 2
Pre Operative view of teeth planned for crowns. The temporary crowns (i.e. provisionals) are in place by the restorative dentist. Tissue health appears within normal limits upon first glance.
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Preoperative radiogaphs of this case, showing margins of crown on tooth #19 are rather proximate to the bone on these teeth. Traditional radiographs are, however, two dimensional in nature. This means that regular dental x-rays do not show the full three dimensional nature of the teeth and associated problems when they occur.
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Temporary crowns are removed and we observe a relatively normal gingival sulcus/probing depth relationship. Temporary cement, which has beneficial antimicrobial properties, remains on teeth.
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Tissue reflected away (below) demonstrates that crown margin would be proximate to the furcation entrance of teeth #18 & #19. A Class II furcation involvement (advanced bone loss) is noted with tooth #19. Horizontal probing depth of this furcation measures 2-3mm.
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Another photo of the same area below demonstrates an even bigger problem existing with tooth #18. A Class II furcation involvement (advanced bone loss) is also noted here which has a horizontal probing depth of this furcation measuring nearly 4mm.
If crowns are placed without attending to these problems, continued bone loss may occur over time which can be instigated by a host of factors, including placing a retraction cord to secure the impressions. End result could be tooth loss.
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In this case, the teeth are reshaped (below) to eliminate the furcation involvement and create a flat, healthy, and maintainable situation for the patient as well as the dental hygienist during periodic continuing care appointments (i.e. regular cleanings).
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The gum tissue is sutured below using micosurgical dissolving sutures and the temporary crowns will be replaced.
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The final porcealin fused to metal crowns have been placed (below) maintaining the contours of the teeth created at the time of surgery. Note the healthly gum tissue resulting from this care as well as the margin placement of these crowns which lends itself to optimal periodontal health. In this case, metal struts were used in the furcation areas to help minimize the need for further tooth reduction and minimize the subsequent need for pre-prosthetic endodontic therapy.
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Above mentioned cases are courtesy of Dr. Daniel Melker (Clearwater, FL)
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