A staged approach of implant placement in immediate extraction sockets for preservation of peri-implant soft and hard tissue.

Esthetic zone restoration is a challenging aspect in implant dentistry because of two critical factors such as level of bone support and soft tissue dimensions. Preservation of healthy peri-implant tissues is of primary importance for ensuring better esthetics over an extended period. The aim of the present case-series was to evaluate a new staged approach of implant placement in immediate extraction sockets for preservation of peri-implant soft and hard tissues. Four subjects scheduled for extraction of teeth in the esthetic zone with neither a periapical nor periodontal infection and with thick tissue biotype were included. For all the subjects sand blasted, large grit, acid etched platform switched implant with a diameter 2 mm less than the diameter of extraction socket and a conical abutment-implant connection (Morse taper) were placed 2 mm below the crest of the socket, with almost 2 mm gap between the labial plate and the implant with shoulder placed palatally/lingually. The implants were loaded after 2 months healing period and followed for a period of 1-2 years. In all the four patients there was preservation of both hard and soft tissues around the implant with a good esthetic outcome in all the follow up visits. Integrating immediate placement with stable implant-abutment connection, platform switching concept and careful case selection, we can achieve a very good esthetic outcome.

INTRODUCTION

The evolution of implant dentistry has continued with significant advances in biomaterials and clinical techniques through ongoing research and development. To a large extent this evolution has reflected the change in the thinking pattern of individuals coming to dental clinics for treatment now-a-days.

Implants can be placed at different timings after tooth extraction; accordingly descriptive terminologies used are immediate placement (in post extraction sockets), early placement with soft tissue healing (after 4 to 8 weeks of extraction), early placement with partial bone healing (after 12 to 16 weeks of extraction), and late placement (after 6 months or greater than 6 months after extraction). It has been proposed that implant placement in the fresh extraction socket has many advantages as this procedure can counteract the tissue modeling that occurs after the extraction of the tooth, hence preserve the dimensions of the alveolar ridge giving an esthetic benefit, along with additional benefits like fewer surgical sessions and shorter treatment periods.[1] However, animal studies done on dogs proved that implant placement in a fresh extraction socket might result in an early hard tissue fill of marginal defect, but in the later phase results of tissue remodeling and newly formed bone may in part be lost.[234] The buccal bone wall was proved to be more susceptible to resorption than lingual due to thinness and the presence of a large amount of bundle bone.[35] Surgical trauma inflicted along with flap elevation, root extraction and implant installation were also proposed to influence the bone remodeling.[2] Thus, immediate implant installation apparently failed to interfere with the process of hard tissue resorption and consideration of this factor while placing an implant in fresh extraction socket was suggested. However, a human study to evaluate the dimensional alterations of hard tissues that occur after immediate placement of implant following tooth extraction noted that the marginal gaps in buccal and palatal/lingual locations were resolved through new bone formation from inside of the defects and substantial bone resorption from the outside of the ridge, but at no site was the surface of the implant devoid of bone coverage.[5] Esthetic success of these implants was also studied and proposed to depend on ideal three dimensional implant position, adequate buccal bone over the implant surface, and tissue biotype. A retrospective review on the esthetic outcomes of immediate implant placement was reported with a high degree of predictability to integrate, thus suggesting the requirement of careful case selection and high surgical skills for achieving a good esthetic outcome.[6] Accordingly, recommendations were made to place implant shoulder 1 to 2 mm lingual to the emergence of the adjacent tooth to ensure maintenance of an adequate width of buccal bone as well as stable mucosa over the buccal implant surface, proper apico-coronal position or depth of implant placement and selecting thick tissue biotype to minimize resorption and maximize esthetics.[6] It has been postulated that the location of implant placement, thickness of buccal bone crest and the size of the horizontal buccal gap significantly influence the ridge alterations following immediate implant placement and only if situation demands augmentation procedures are needed to achieve adequate bony contours around the implant.[78910] There is also development toward new and innovative implant designs with surface treatments and improved abutment-implant connections for decreasing the crestal bone loss.[1112]

Keeping in mind these factors, the clinician must make very important decisions, as to recommend the best time to place an implant and also the appropriate biomaterials to be used. The need for functional and esthetic outcomes as well as desire for reduced treatment times between tooth extraction and implant placement must be weighed carefully against the pretreatment conditions of the site, dimensional changes that will occur following extraction, the predictability of the planned treatment approach and the related risk of complications.

Another concept reported in literature that is proved to give an esthetic benefit is platform switching, which is designated to the usage of smaller diameter abutments to larger diameter implants.[13] A study pointed out that platform switching concept might compromise the emergence profile especially in anterior cases.[14] However, subsequent biomechanical and histological studies, case reports and randomized clinical trials reported on this concept have proved that the marginal bone loss around platform switched implants was significantly less than around platform matched implants.[151617181920212223242526272829303132] The esthetic advantage is ascribed for two reasons: First one being the increased surface area to which the soft tissue could attach and the decrease in crestal resorption needed to establish a biologic width; second one being the increased distance between the implant abutment junction and the adjacent bone, which in turn limits the resorptive effect of the implant-abutment junction associated inflammatory cell infiltrate.[32]

CASE REPORTS

The following are some cases where in immediate placement of implant after tooth extraction was done with applied platform switching concept.

Case 1

A 30-year-old male patient reported to the clinic with a traumatic injury to the upper jaw. He was diagnosed with complicated crown-root fracture of maxillary right lateral incisor [Figure 1a] and subluxation of maxillary right and left central incisors. The lateral incisor had worst prognosis and there was no provision to plan for a post core because of the difficulty to get a ferrule, hence extraction and prosthetic replacement were the treatment of choice. He was informed about the possibilities of removable denture, fixed prosthesis, and implant therapy. As patient was interested in implant therapy, and as we felt him to be an ideal patient, we planned for immediate placement of implant after extraction of the tooth. Patient received 1 g of amoxicillin/clavulanate 1 h before surgery and continued with 2 g per day for 5 days. Under local anesthesia, a platform switched (0.6 mm), sand blasted, large grit, acid etched surface treated implant of length 11 mm and diameter 3.5 mm (Ankylos implant design, Friadent GmbH, Mannheim, Germany) was placed in the post extraction socket with the platform of the implant positioned 2 mm below the alveolar crest level. [Figures 1b and 2a] After a 2 month healing period, definitive prosthesis for the lateral incisor was planned with a zirconium ceramic abutment and a zirconium crown. [Figures 2b and 3a] In the recall visits as there was discoloration of right and left central incisors and as both the teeth did not respond for vitality tests, they were planned for endodontic therapy. Radiographs taken immediately after placement of implant, in 3 months, 1 year, and 2 year follow up are represented in Figure 4 and clinical picture in the 2 year follow up in Figure 3b.

Figure 1

(a) Pre-operative photograph showing fractured maxillary right lateral incisor (b) Photograph showing immediate implant placement in the extraction socket

Figure 2

(a) Gingival former in place (b) Zirconium abutment in place

Figure 3

(a) Permanent crown in place (b) Photograph showing soft tissue level 2 years after loading

Figure 4

(a) Radiograph immediately after implant placement (b) Radiograph taken 3 months after loading (c) Radiograph taken 1 year after loading (d) Radiograph taken 2 years after loading

Case 2

A 23-year-old female patient reported to the clinic with a chief complaint of over retained primary canine in the right mandibular region. The primary tooth was extracted and a platform switched implant of length 11 mm and 3.5 mm diameter (Ankylos implant design) was placed in the post extraction socket. Radiographs taken pre-operatively, immediately, and 3 months after placement of implant and 1 year after loading are represented in Figure 5.

Figure 5

(a) Pre-operative orthopantomograph (b) Radiograph immediately after implant placement in extraction socket (c) Radiograph taken 3 months after placement (d) Radiograph taken 1 year after loading

Case 3

A 35-year-old female patient reported to the clinic with a chief complaint of fractured root canal treated maxillary left lateral incisor which was extracted and followed with the placement of a platform switched implant of length 11 mm and 3.5 mm diameter (Ankylos implant design) in the post extraction socket. Radiographs taken immediately and 3 months after placement of implant; and 6 months and 1 year after loading are represented in Figure 6.

Figure 6

(a) Radiograph immediately after implant placement in extraction socket (b) Orthopantomograph 3 months after implant placement (c) Radiograph taken 6 months after loading (d) Radiograph taken 1 year after loading

Case 4

A 28-year-old male patient reported to the clinic with a chief complaint of fractured root canal treated maxillary right central incisor which was extracted and followed with the placement of a platform switched implant of length 15 mm and 3.5 mm diameter (Ankylos implant design) in the post extraction socket. Radiographs taken pre-operatively and immediately after placement of implant; and 1 year after loading are represented in Figure 7.

Figure 7

(a) Pre-operative radiograph (b) Orthopantomograph immediately after implant placement in extraction socket (c) Radiograph taken 1 year after loading

DISCUSSION

The success rate of the single implant therapy depends not only on restoring the function, but also on the level of integration that we provide for the restoration so that it harmoniously sinks into the patient's overall appearance. In clinician's view, success of implant restoration depends on the change in the peri-implant bone level and the surrounding soft tissue; and for the patient it is the esthetics and his/her level of satisfaction. The patient satisfaction has more importance when we have the restoration located in the esthetic zone. However, the esthetics associated with the final implant restoration is greatly affected by both the soft and hard tissue changes. Hence, if clinician's criteria are met, indirectly they will fulfill the patient's criteria. Thus, if we can take care of the shrinkage of the adjacent interdental papillae and the loss of the scalloped tissue contour around the implant restoration and minimize the crestal bone loss; the anterior implant restoration will have good esthetics. Crestal bone remodeling and resorption during the first year following immediate implant placement leads to compromise in the treatment outcome that are reported in literature,[2345] and ways to overcome this also described.[6] In the cases presented we could appreciate a good esthetic outcome, the success of which might be ascribed to many reasons [Table 1]. Neither periapical infection nor periodontal is responsible for extracting the tooth, which might be the first and foremost reason. Another positive factor in case selection was the thick tissue biotype. The surgical trauma was also minimal as there was careful extraction of the tooth and no flap elevation procedure. Sand blasted, large grit, acid etched implant with a diameter 2 mm less than the diameter of extraction socket and with a conical abutment-implant connection (Morse taper) was selected. The implant placement factors that might have led to success were palatal/lingual placement of shoulder, almost 2 mm gap between the labial plate and the implant, 2 mm below the crest of the socket and the implant was not immediately loaded. The implant abutment factors were conical connection that lacks a microgap between abutment and implant, and usage of zirconium ceramic abutment which is proved to be biocompatible, both not favoring the accumulation of bacteria when compared to external/internal hex and titanium abutments, respectively.[11] Incorporation of platform switching concept with a circumferential horizontal mismatch of 0.6 mm added to the clinical success as it was proved to have minimal ill effects on the biomechanical environment of implants.[20]

Table 1

The factors to be considered while placing an implant in immediate extraction socket

Thus, by integrating immediate placement with platform switching concept and careful case selection, we could achieve a very good esthetic overcome.

CONCLUSION

Platform switching is not the only way to control circumferential bone loss around dental implants, but it is one of the ways to get a better results. Diagnosing and treatment planning are very critical when the timing of the implant placement is concerned. When we integrate everything we can get a very good esthetic outcome as presented, thus increasing the quality of life of patients.