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ePaper created 2018-02-22, 10:39:24 | version 1.38.0
28 RESTORATIVE Dental Tribune Middle East & Africa Edition | 2/2017 Customized Lithium Disilicate Abutments for Implants in the Esthetic Zone By Dr. Ali Tunkiwala, India & Danesh Vazifdar, India Technological advances in recent past have provided the much need- ed impetus to the clinicians to pro- vide an immediate implant solution to the patients immediately after extractions, thereby truncating the overall treatment time while provid- ing a biologically safe and estheti- cally impeccable result. Based on the time at which the im- plant is placed after extraction of the offending tooth, implant placement protocols are classified as Immedi- ate placement (T1) , Early placement with soft tissue healing (T2- 6-8 weeks), Early placement with partial bone healing (T3- 8-12 weeks) and Late placement (T4 - >12 weeks)1. involves T1 protocol immediate placement of implant in extraction socket and has been a matter of discussion in literature for several years1. The shortened treatment time and the immediate gratification that this protocol can offer to the patients is its greatest advantage. Although literature has shown, beyond doubt that the bundle bone is lost on aver- age by 1mm irrespective of whether implant is placed in extraction sock- et or extraction socket is left as it is 2, there are several other advantages of immediate placement; the great- est being, the ability to support the soft tissues with an immediate pro- visional. For this protocol to work predictably, it is mandatory for the clinicians to place the implant in a perfect 3 dimensional position1 such that the screw access hole of the final abutment would emerge from the cingulum area. An error in place- ment is catastrophic and it results in maligning of the protocol. When done right, in a wisely chosen case, immediate extraction and place- ment is a huge asset in managing implants in the esthetic zone. Once the implant is inserted in its correct, prosthetically driven posi- tion, customized abutments can be used to take the result to an accu- rate, predictable end point that looks seamless when compared to natural teeth and soft tissues. There are a large number of abutment options available to clinicians today, how- ever an abutment that is customized to the gingival architecture gener- ated by a well contoured provisional restoration, is by far the most desir- able in term of achieving a perfect emergence profile for the implant restoration in the esthetic zone. This customization can be done with me- tallic as well as ceramic abutments. Titanium and other grey metals are a distinct disadvantage in thinner biotypes, as they cast a dull shadow, leading to a show through of the abutment in the final result. Al- though zirconia has been the ‘go-to’ material for customization of abut- ments in the anterior zone, recently lithium disilicate abutments have been introduced that provide several additional benefits over zirconia as abutments. This article describes a case of im- plant placement with T1 protocol and use of customized IPS e.max abutment to provide a road map to achieve an esthetically good result. Clinical Case Assessment Before finalizing on the decision of doing immediate extraction and placement in the esthetic zone few parameters need to be assessed3. A. Free Gingival Margin Level of in- volved tooth The more coronal the free gingival margin of the affected tooth as com- pared to adjacent teeth the better the chance of getting a good esthetic result. In such cases slight mucosal recession will not affect the esthetic outcome of the case adversely. B. Tooth Shape Rectangular/Square teeth forms are better replaced with immediate ex- traction protocols. A triangular tooth means that the sharp interdental soft tissue peak may be lost due to trauma from extraction and pros- thetic procedures leading to a dark triangle in the end result that will need exacting prosthetic protocols to be employed to salvage the situ- ation. C. Gingival Biotype A thin biotype is more prone to mucosal recession as compared to a thicker one and requires precautions to be taken to prevent show through of the final abutment colour. D. Scallop of Gingival Margin A high scalloped gingival architec- ture is more prone to recession as the thin bone that accompanies the high scallop may be too fragile to hold on to its position once the extraction is done. E. Interproximal Height of bone A greater than 5mm probing depth to bone in preoperative assessment means that the interproximal bone is already deficient. The prognostic value of this bone sounding is evi- dent as in such cases on high bone crest situation the tendency to loose interproximal tissue is higher. F. Upper Lip Line In cases where the patients upper lip is long the chances of success with esthetic immediate implant place- ment are better as the crucial peri- odontal infrastructure will not be readily visible when patient smiles. The higher the lip line the more chal- lenging the case becomes. When all these six factors are fa- vourable the chances of a successful esthetic outcome with immediate extraction and placement protocols are greater. The Case Profile The patient (Fig 1) reported with discolouration of gingival aspect of 12 region. The existing coronal res- toration on 12 had a leaky margin and was not in sync with the overall esthetic appearance of the adjacent tooth. Radiographic examination revealed that the failing tooth was endodontically treated with a metal- lic post (Fig 2). On removal of faulty crown on 12, it was found that the coronal structure of tooth was totally destroyed and saving the tooth was not possible (Fig 3). After the preoper- ative analysis we finalized the use of immediate extraction and implant placement protocol as the patient presented with clinical factors in this favour, especially, the Inter-proxi- mal height of bone, that was within normal limits. In cases of immediate placement after extraction in this region we need to have a plan for im- mediate provisionalization. A provi- sional abutment on the implant was planned that would be used in fabri- cation of a screw retained provision- al using a putty matrix generated from the preoperative casts. This can be done only when implant is placed with good primary stability. The Surgery The extraction is gently carried out without undue damage to the ad- jacent tissues. The socket is cleaned well and the integrity of the buccal cortex is assessed. Only if its intact, immediate placement may be con- sidered, else it’s better to defer it by 6-8 weeks. Raising the flap and the periosteum is strictly avoided to pre- vent mucosal recession from surgi- cal trauma. The implant site preparation is be- gun on the palatal wall with the pilot drill, such that at the end of drilling protocol we do not touch the buccal wall with any drills. The diameter and mesiodistal position of the im- plant in this region should be chosen such that at least 2mm bone is left on both sides between implant and the adjacent tooth. Apicocoronally the implant platform must be 2mm deeper than the CEJ of the adjacent teeth1. When done with the implant placement, the screw access hole should be ideally accessible from the cingulum of the proposed final crown. These principles are univer- sally applicable to all implant place- ment protocols in anterior maxilla. Using these principles, an implant was placed in 12 region (Fig 4). The Provisional Our choice of provisionalization in this case was to use a permanent me- tallic abutment to fabricate the im- mediate provisional crown. A putty matrix of the preoperative cast will aid in making the provisional with Systemp c&b II, which is then fin- ished extra-orally to give perfect contours (Fig 5). The screw retained provisional is kept out of centric as well as eccentric contacts to prevent any loading and micro motion of the implant in its healing period (Fig 6). ÿPage 30 Fig 1: Pre- Operative View of offending tooth #12 Fig 2: Pre- Operative X ray tooth #12 Fig 3: Pre- Operative View of #12 after removal of faulty restoration Fig 4: Implant placed in correct 3 dimensional position Fig 5: Provisional Restoration contoured to mimic natural tooth form Fig 6: Provisional Restoration delivered on the stable implant Fig 7: Gingival architecture formed by provisional at 4 months Fig 8: Customized impression coping for implant level impression Fig 9: Soft tissue mask to reproduce gingival contour on stone model Fig 10: Full contour wax-up for customized E-max abutment Fig 11: Cut-back of full contour abutment for receiv- ing E-max veneer Fig 12: Finalized E-max abutment wax-up on stone model