Pre-surgical orthodontic extrusion of compromised teeth

27 Mar 2018 - 15096

Orthodontic extrusion of teeth that have a compromised periodontium is a viable solution as excellence in implant dentistry must nowadays be achieved not only from an osseointegration survival standpoint, but from an aesthetic point of view, too. According to Misch et al. (1) replacing the maxillary central incisor remains the most challenging procedure in implant dentistry. Interdisciplinary treatment of such cases in adult patients with implants, should consider the orthodontic treatment, especially the orthodontic extrusion, which may offer many benefits by both correcting tooth alignment and correcting the regeneration of periodontal tissues. In their systematic review Mohamed Korayem et al. (4) studied over 79 unique abstracts, describing the benefits of implant site development by orthodontic extrusion, as their conclusion based on the available literature is the fact that the orthodontic extrusion of non restorable tooth prior to implant placement appears to be a valuable alternative to conventional surgical augmentation. Factors that provide success of one orthodontic-implant case are the amount of available bone, the type of the soft tissue, the correct positioning of the implant, the provisional restoration, the design of the abutment and the final crown restoration ( 2,12,14,15,19,20). Achieving the ideal tissue shape is often considered the most difficult aspect of this restorative process (17,18). There are a lot of studies supporting the use of orthodontic extrusion as a treatment approach, which can provide significant gain of both alveolar bone and soft tissue prior to implant placement. Orthodontic extrusion is not new a new procedure (4): there are many case reports of hopeless maxillary incisors that, after slow orthodontic extrusion, achieved optimal aesthetic-restorative outcomes. Such case reports (1, 6,7,8,9,10,11) claimed to prepare optimum implant placement sites with improved aesthetics and healthy peri-implant tissue through orthodontic extrusion, as the most effective and minimally invasive modality. Although osseointegrated implants have shown consistent improvement in terms of their application in cases of tooth loss, the quality and quantity of the alveolar bone and gingival tissues remain the determining factors for the prognosis of the implant rehabilitation. Rehabilitation success depends on the osseointegration of the implant, health of the hard and soft tissues and harmony with the natural teeth. In their clinical report Stephen Chu and Denis Tarnow (14) give basic concepts for orthodontic extrusion and emphasize a new diagnostic periodontal classification for the pre-treatment anatomy, providing a better understanding of the orthodontic biomechanical principles and techniques that should be selected based on anatomical considerations for each patient. Different types of soft tissue response to orthodontic extrusion have been classified, and described as follows:
Type 1: Increase of width of attached gingival and overall soft tissue width.
Type 2: Increase of overall soft tissue width with no effect on the wight of attached gingiva.
Type 3: Width of attached gingiva and overall width of soft tissue are unchanged.

In conclusion the authors claimed that mastering the techniques of orthodontic extrusion is an invaluable addition to the interdisciplinary practice as they offer predictable results for clinicians and patients alike.
Another interesting article that gives us directions about pre-implant orthodontic treatment is Maurice and Henry Salama’s work (5), who proposed a classification that systematizes the wide range of regenerative potential of common extraction site topographies. They give us 3 types of extraction sites and the important consideration that they come with.

A contemporary approach to achieve optimal implant aesthetic-restorative outcomes requires the knowledge to properly diagnose, coordinate, and execute complex interdisciplinary care. Implant site development utilizing orthodontic extrusion requires an understanding of many important concepts and principles of both disciplines of orthodontics and periodontics.

Clinical case:

Fig. 1

The initial situation of the patient.

In this case, an acute inflammation was presented in the first visit and antibiotic therapy was prescribed. In the next stage a calculus removal was performed and probing was carried out, then oral hygiene instructions were given to the patient. Two main photographs were taken: one full-face with maximal smile and visible dentition and the other photograph of the upper jaw with retracted lips and  a black contrastor (Flexipalette, Smile Line Powered by StyleItaliano).  A short video was shot with the patient asked by the clinician to go through a state of rest to maximal smile position. In a spontaneous conversation the patients also expressed their expectations, concerns and opinion about the final aesthetic result from the dental treatment.

Fig. 2

After periodontal initial treatment.

Fig. 3

After that, an endodontic treatment of the extruded tooth was provided and brackets, with soft ligature were placed on all the teeth of the maxilla. The extrusion was provided with a round wire 14 CuNiTi. The bracket of the extruded tooth was placed 1mm more apically every two weeks and activation was performed. When needed the bracket on the extruded tooth was rebonded. The teeth adjacent to the extruded one were blocked with a ligature.

Fig. 4

Orthodontic extrusion thanks to apical repositioning of the bracket. The extrusion was performed until there was no more space, apically, on the crown to cement the bracket.

Fig. 5

 Before extracting the tooth after the orthodontic treatment, an x-ray was taken that shows 1cm vertical bone gain after the orthodontic extrusion. 

Fig. 6

Soft tissues after extraction: occlusal and frontal view.

The incisor edge position was determined, according to the aesthetic rules and the preferences of the patient. The position of the future smile was determined by using a web based smile design software VisagiSmile which uses the facial reading, as well as the psychological characteristics and wishes of the patient according to the Visagism concept.

Fig. 7

The adhesive fiber reinforced bridge after the extraction.

A periodontal therapy  was performed and after 2 months an implant surgery was planned.

Fig. 8

 3D Cone Beam scan before surgery. A cone beam examination was requested to evaluate the hard tissue.

Fig. 9

Placing of the implants. 

 The surgical procedure started with a crestal incision and reflecting of a mucoperiosteal flap. The entire thickness of the gingival tissue was reflected with the flap.

The first drill was a trepanning drill for the biopsy, which was treated according to the rules and sent for histological examination.

The implants placed (TM; Zimmer Biomet, Warsaw, IN, USA) were 4.1 mm in diameter and 11.5 mm in length and were placed according to the recommended protocol at a minimum insertion torque of 20 N·cm. The vertical positioning of the implants was determined 2-3 mm from the future CEJ and  the implant platform was not placed according to the anatomical bone structure. 

Fig. 10

Stability of the implants was evaluated using an ultrasound method in terms of ISQ units (Osstell Mentor; Integration Diagnostics, Göteborg, Sweden) during the surgery. Two measurements were performed with a torque wrench, on the vestibular and mesial sides, and the average value was recorded.Osstell measurments.

Fig. 11

A bone graft was performed around the implants.

Fig. 12

Sutures around healing abutments. 

The sutures were removed on the 10th day after surgery. 

Fig. 13

 CAD/CAM design for the first provisional crowns.

Immediate provisionalisation was performed once primary stability of all implants (35 N·cm or more, ISQ above 55) was achieved. The provisional abutments  were scanned in the mouth with a Digital intraoral scanner (Bluecam, Cerec, Dentsply  Sirona). The field was isolated with a sterile rubber dam. CEREC Powder was carefully applied onto the abutments and the adjacent teeth. The teeth were precisely scanned and correlated in the CEREC Software. 

The shape of the restoration was designed using CEREC 4.0 and was milled in the CEREC Milling Unit. 

 

Fig. 14

The emergency profile of the first provisional crowns. 

Lava Ultimate blocks were used for the fabrication of the crowns. The construction was tested and was then cemented out of the mouth with composite cement (Choice, Bisco).

Fig. 15

First provisionals in the mouth. The restoration was out of occlusion.The vertical level was corresponding to the CEJ of the adjacent teeth. 

Fig. 16

The gingival profile after de-cementation of the first  provisionals.

The first provisional restoration was removed after the second month and a new provisionals were fabricated. The vertical level corresponded to the aesthetic project and harmonized with the adjacent teeth.

Fig. 17

Second provisionals.

After the second month a second provisionals were placed in order to shape the emergence profile of the restoration.  

Fig. 18

The soft tissue profile after second provisionals – frontal view.

Fig. 19

The soft tissue- occlusal view.

After shaping the individual emergence profile, a permanent construction with individualized abutments was placed. 

Fig. 20

The final construction, made by Dr. Vincenzo Musella, MDT

Fig. 21

The individual abutments

Fig. 22

The final constructions after cementation.

After 6 months the patient was called for follow-up visits and the implants were clinically and radiologically examined.

Fig. 23

Patient’s smile in the end of the treatment.

Fig. 24

The final result 4 years later.

Fig. 25

The tissues are still stable four years after the treatment.

Fig. 26

Every 6 months the patient was called for follow-up visits and the implants were clinically and radiologically examined.

 

The radiographic examination 4 years later:

a- CBCT shows implant 11

b- CBCT shows implant 21

c- panomaric x-ray of the maxilla

d- intraolar x-ray

Fig. 27

The biopsy, which we took at the time of the implant placement confirmed mostly formed by lamellar bone and only occasionally we could find woven bone. No osteoclasts were detected (no resorption) but also very few osteoblast are present. Medullary spaces are formed by areolar tissue with a lot of mast cells. In conclusion the biopsy is formed by a fairly good trabecular bone with a good amount of B%, lamellar structure and in a cellular steady state.

 

Conclusions

In the last 8 years 18  implants in  the aesthetic zone were placed on  14 patients with an average age of 54 years. All the extruded teeth had a vertical and horizontal bone gain average  and bone gain. The quality of the bone was type 2 or 3 according to Misch and the implant stability was average 75ICQ and 40n/cm. All the implants were osseointegrated and a vertical bone gain of average 0,6mm was observed  after 2 years recall. All the patients were satisfied from the pink and  white aesthetic score.  No complications were observed during the healing process. At the end of the  second month in all patients sufficient volume of attached gingiva was formed which could be further shaped and contoured by the second provisionals or the definitive restoration. 

Following the results after one year, according to the criteria for success of implants, introduced by Szmukler et al., a success rate of 100% was registered. No bone loss was observed after the second month, while at one year the mean bone gain was observed -0.34mm. All the implants were perfect  ossteointagrated   and there was no bone loss  or soft tissue remodelling after the 4 years recall period. 

In the presented clinical case 1 cm of vertical bone gain was achieved. The main advantage of this technique is that bone quality and quantity is obtained only by means of orthodontic extrusion without severe surgical interventions, which could provide  sufficient volume of bone to place implants and  good pink aesthetic score. Even greater biological significance has been the consequence that, thanks to this slow and gradual extrusion, an approximate bone gain was achieved around the adjacent lateral incisors.This made it possible to preserve them naturally.

Conclusion: Orthodontic extrusion of non-restorable teeth before placing implants is a very good alternative to surgical augmentation in implant site development. 

Bibliography

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