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  • Implantology

     

    Immediate Loading in Implant Dentistry:

    Prerequisites for Success

     

    Hassan Maghaireh - BDS, MFDS, MSc

    BDS (Cairo University), MFDS (Royal College of Surgeons- Edinburgh), MSc Implants (University of Manchester)

    H. Teaching Fellow Implant Dentistry, University of Manchester

    Head of Scientific committee - British Academy of Implant & Restorative Dentistry (BAIRD)

    Private Implant Practice, Clarendon Dental Spa | Leeds - UK | www.treatmyimplant.com

     

    ABSTRACT

    When people have dental implants in their jaws, they usually wait several months for the bone around the implants to heal before the implants prosthetic restorations are attached to the implant. During this healing period they use removable dentures, adhesive bridges or accept having a gap. However, more recently immediate loading of dental implants started to be a popular and predictable treatment option which meets our patient’s demands for better, faster and cheaper implant therapy. The up to date evidence from the dental literature supports immediate loading when proper case selection, good clinical training and good implant system are observed. This case report demonstrates a case of immediate loading for an upper premolar case detailing the clinical steps of immediate loading in dental practice.

     

    KEYWORDS

    Implants, Cosmetic, Immediate, Loading.

     

    INTRODUCTION

    Missing teeth and supporting oral tissues have traditionally been replaced with dentures or bridges to restore the ability of patients to eat and speak and improve appearance. However, in several instances, patients are not satisfied with the function of removable dentures and it is not always possible to place a fixed bridge if the number of remaining abutment teeth is insufficient.

     

     

    Since the 1970s, osseointegrated dental implants as described by Branemark1 have offered an alternative. They are surgically inserted into the jaw bones to support a dental prosthesis and are retained because of the intimacy of bone growth onto their surface (osseointegration). Dental implants have undoubtedlybeen one of the most significant scientific breakthroughsin dentistry over the past 30 years. Albrektsson2 and his group suggested that primary implant stability and lack of micromovements are considered to be two of the main factors necessary for achieving predictable high success of osseointegrated oral implants. A successful osseointegrated oral implant is anchored directly to bone, however, in the presence of movement a soft tissue interface may encapsulate the implant causing its failure as described by Brunski et al.3 in 1979. To minimise the risk of soft tissue encapsulation, it has been recommended by Branemark and his group to keep the implants load free during the healing period: 3 to 4 months in mandibles (lower jaws) and 6 to 8 months in maxillae (upper jaws).

     

     

    In general, during the healing period removable prostheses are used, however, many patients find these temporary prostheses rather uncomfortable and it would therefore be beneficial if the healing period could be shortened without jeopardising implant success. In 1990, the first longitudinal clinical trial was published by Schnitman et al.4 suggesting that implants could be loaded immediately or early in the mandibles of selected patients. Nowadays, immediately and early loaded implants are commonly used, particularly in mandibles of good bone quality.

     

     

    Esposito et al. have published one of the well conducted systematic review on immediate loading in implant dentistry.5 Although this Cochrane review was published 3 years ago, it is still considered one of the best published in this field as it has included 26 random controlled trial. The authors concluded that immediate loading can be considered a safe and predictable procedure when patients are well selected and the clinicians have received good training. Immediate loading should be avoided in patients with para functional habits and will require implant placement within the prosthetic envelop to facilitate building the temporary implant prosthetic components and the immediate loading process. It could make more clinical sense to load an implant immediately if the implant was inserted with a sufficient torque and if there are not other factors believed to negatively influence its prognosis. It was shown that in the case of poor primary implant stability or other suspected negative prognostic variables, it might be preferable to wait for a conventional healing period.

     

     

    One interesting finding in that systematic review was that some specific factors might have played a determinant role in the final outcome in some of the trials. Factors such as the surgical skill of the operators, or the flapless placement of dental implants, which is technically demanding, might have contributed to the sub-optimal success rates of immediately loaded implants. Insertion torque is another factor which was associated with subsequent implant failure, but there is no conclusive evidence as to the minimum insertion torque required to prevent failure. In one random controlled trial published by Ottoni et al. in 20056 a strong correlation between implant failures and the initial insertion torque of the implants was found. In fact 90% of implants inserted with a 20Ncm torque failed when loaded immediately, versus only 8% placed with at least 32Ncm torque in the immediately loaded group. More recently, another random controlled trial published in 2012 by Cannizzaro and his group in Italy compared success rates of immediately loaded single implants placed according to a split-mouth design with insertion torques between 25 and 35Ncm or superior to 80Ncm in 50 participants.7

    Seven of the implants placed with 25 to 35 Ncm torque failed versus none of the implants placed with more than 80Ncm. Cannizzaro et al. concluded that a high degree of primary stability at implant insertion is a key prerequisite for successful immediate or early loading procedures.

     

     

    CASE REPORT

     

    Mrs K J 50-year old female presented with missing upper right 1st premolar tooth which was extracted few weeks before due to vertical crack within the tooth following a direct trauma to that area (Fig. 1). The referring dentist had advised that the tooth was judged to be unrestorable and needed extraction. Mrs K J was referred to us for implant placement and restoration. However, alternative treatment options were discussed with the pros and cons of each option with her - removable denture, adhesive bridge, conventional bridge or dental implant.

     

    Mrs K J was very keen on the dental implant option and study models, wax up and surgical guide were prepared. Peri-apical radiograph with ball bearing was taken and utilised in planning the implant placement (Fig. 2). Full dental examination revealed a stable dentition with no signs of dental or gum disease. A full medical history was also taken revealing no significant medical history and no known allergies. A letter detailing the treatment plan and associated risks were sent to the patient and one week before the implant placement operation, a consent form was signed discussing the possibility for immediate loading at the time of surgery. A temporary adhesive Rochette was fitted using flowable composite. This adhesive bridge was also used as a communication tool with the lab and the patient who was happy with the shape and shade of this temporary adhesive bridge. (Fig. 3)

     

    (Fig.1)

     

    (Fig.2)

     

    (Fig.3)

     

     

    Eight weeks following the tooth removal, the patient presented for implant placement surgery. The lady was given 2gm preoperative Amoxicillin 1 hour before surgery. Three sided flap was raised and the upperright 1st premolar (UR4) osteotomy was prepared using Straumann single use drills and sequential drilling under copious irrigation. A 4.1 x10mm Straumann BLT implant was placed within the prosthetic envelope to crestal level and a primary stability with 45NCM insertion torque was achieved. (Figs 4,5)

     

    (Fig.4)

     

    (Fig.5)

     

     

    While we have maintained 1.5mm labial bone thickness, the implant apex perforated the apical part of the labial plate in order to achieve correct 3D implant placement and Cerabone and Jason membrane from Botiss were used later on to cover the apical perforation and to create a labial convexity at the coronal one-third area.

     

     

    A Straumann temporary abutment was adjusted and trimmed then fitted using 35Ncm torque. A teflon tape was used to protect the connection screw and then a small metal post was used to maintain the screw access channel. A temporary ready-made crown was adjusted and fitted on the metal temporary abutment using protemp material. Once it set hard, the metal rod and the teflon were removed and the temporary crown was screwed out. (Figs 6-13)

     

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    Sub-gingival concavity and supra-gingival convexity were achieved during the temporary crown contouring process in order to achieve correct soft tissue conditioning using the temporary crown. (Figs 14-16)

     

    (Fig.14)

     

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    (Fig.16)

     

     

    4/0 Monocryl single threaded sutures were used with vertical mattresses at the papillae area and sling suture around the temporary crown to achieve good gingival stability. Occlusion was checked and adjusted to allow 30microns clearance but no lateral interferences. The patient was very happy to walk home with a dental implant and an immediately loaded temporary crown at the UR4 area which was within her smile line. (Figs 17,18)

     

    (Fig.17)

     

    (Fig.18)

     

     

    The implant was allowed to heal over 12 weeks during which the temporary crown was removed, recontoured and polished at week number 6, 8 and 10 to achieve gradual soft tissue conditioning (Fig. 19).

     

    (Fig.19)

     

    (Fig.20)

     

     

    At the 12th week, the temporary crown was unscrewed and a well contoured peri-implant soft tissue was observed with the correct gingival emergence profile(Fig. 20). Open tray implant impression was taken using customised impression post (Fig. 21). A screwretained implant crown was constructed at the lab. The final screw retained crown was fitted in place using the recommended 35Ncm torque, the cover screw was protected with a layer of isolation teflon tape and flowable composite was used to cover the screw access channel. Occlusion was checked and post-operative oral hygiene instructions were given. (Figs 22,23)

     

    (Fig.21)

     

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    (Fig.23)

     

     

    CONCLUSION

    Dental clinicians are under pressure from their patients to provide dental treatment at high standards, at low cost and in the minimal time possible. Dental implantologists are no different as implant patients find it difficult to cope with multiple visits and long helming time while suffering with removable provisional restorations and or adhesive bridges which are at higher risk of de-bonding. Furthemore, it has been suggested that removable provisional restorations could negatively influence the peri-implant soft tissue healing and maturation. All the above, have supported the idea of immediate loading in implant dentistry whenever clinically is possible.

     

    There is strong evidence from well conducted clinical studies that immediate loading in implant dentistry can be a safe and predictable treatment modality. However, evidence based practice suggests that the risk of implant failure can be substantially minimised by proper patient selection and well-trained operators. To that extent, the evidence suggests that under ideal conditions surgeons are able to achieve a high rate of success in loading implants immediately. However, a high value of insertion torque (about 35Ncm) seems to be one of the prerequisites for a successful procedure.

     

    REFERENCES

    1. Brånemark P-I, Hansson BO, Adell R, Breine U, Lindström J, Hallén O, et al. Osseointegrated implants in the treatment of the edentulous jaw. Experience from a 10-year period. Stockholm: Almqvist & Wiksell International. 1977;16:1-132.

    2. Albrektsson T, Brånemark PI, Hansson HA, Lindström. J. Osseointegrated titanium implants. Requirements for ensuring a long-lasting, direct bone-to-implant anchorage in man. Acta Orthopaedica Scandinavica. 1981;52(2):155–70.

    3. Brunski JB, Moccia AF Jr, Pollack SR, Korostoff E, Trachtenberg DI. The influence of functional use of endosseous dental implants on the tissue-implant interface. I. Histological aspects. Journal of Dental Research. 1979;58(10):1953–69.

    4. Schnitman PA, Wöhrle PS, Rubenstein JE. Immediate fixed interim prostheses supported by two-stage threaded implants: methodology and results. Journal of Oral Implantology. 1990;16(2):96–105.

    5. Esposito M, Grusovin MG, Maghaireh H, Worthington HV. Interventions for replacing missing teeth: different times for loading dental implants. Cochrane Database of Systematic Reviews 2013, Issue 3. Art. No.: CD003878. DOI: 10.1002/14651858.CD003878.pub5.

    6. Ottoni JM, Oliveira ZF, Mansini R, Cabral AM. Correlation between placement torque and survival of single-tooth implants. International Journal of Oral and Maxillofacial Implants. 2005;20(5):769–76.

    7. Cannizzaro, Gioacchino, et al. Immediate loading of single implants inserted flapless with medium or high insertion torque: a 6-month follow-up of a split-mouth randomised controlled trial. Eur J Oral Implantol. 2012;5(4):333-42.