In the second of a two-part article, Jamie Kerr discusses the next stages of dental implant treatment – surgery, restoration and maintenance.
As formal training is advised prior to performing surgical and restorative implant treatment, the following sections will only briefly detail the stages that are required, in order to provide a baseline knowledge to the reader.
Following full case assessment and treatment planning, and the patient consenting to proceed with the chosen treatment, implant placement is required. If the patient still has their tooth, then a decision can be made whether to place the implant simultaneously at the time of extraction. This is not recommended in cases where there is evidence of pathology/infection associated with the tooth in question and is not advisable for clinicians at early stages in their dental implant career. The traditional and generally most commonly used protocol is adopting the staged approach. Generally, the offending tooth is extracted, and a period of six to eight weeks healing time is allowed prior to surgical implant placement.
The surgical technique varies between clinicians and it must be noted that deviations will always apply depending on the clinical case. After providing adequate anaesthesia, which can be aided with use of topical anaesthetic and use of a painless-injection system (eg Quicksleeper by Dental Hi-Tec) (Jung et al, 2017), a flap is raised to allow assessment of the underlying bone. Generally, the flap is designed to provide adequate direct vision, whilst reducing the amount of trauma to the soft tissues. When adequate bone is available, and no grafting is required, an incision slightly palatal to the crest of the alveolus and around the adjacent teeth is completed, making sure to lift the papillae together with the flap (Norton, 2001). Unless large grafting is required, it is preferred to avoid using large vertical relieving incisions, and to try and preserve the interdental papillae at all times. When wider flaps are required for grafting, vertical relief is used making sure that they are designed to preserve the interdental papillae on the adjacent teeth (Norton, 2001).
Once the flap is reflected adequately, a guide or stent can be placed to aid in positioning of the osteotomy. Preparation of the osteotomy will vary between different manufacturers and implant systems, but generally they use a combination of a pilot drill followed by width increasing drills, all prepared to a pre-determined length to allow the implant collar to be ideally positioned 1.5-2mm below the ACJ of adjacent teeth (Norton, 2001).
As outlined previously, a minimum mesio-distal interproximal distance of 7mm is required for implant placement. Generally, a minimum of 2mm of bone is advised between the implant and adjacent teeth (3mm between implants), to support the interdental soft tissues (Nicholson, 2016). A minimum width of 2mm of buccal bone is ideal and implant position should reflect this (Warreth et al, 2017). The osteotomy is prepared under saline irrigation with all required burs or using a slow-drilling technique with the width increasing burs (after initial preparation with pilot drill under saline irrigation). This technique allows for collection of autogenous bone, which can be used to bulk up bone around the implant once it is positioned. Once completed, the implant is inserted to the desired depth at an adequate torque using a handpiece or by hand using a torque wrench (or a combination of both).
If a high torque (>35Ncm) is achieved when inserting the implant then it has high primary stability and the clinician can choose whether to bury the implant, place a healing cap/sulcus former or to restore it immediately with a provisional restoration. If a provisional restoration is chosen, then this can be premade by a lab (especially if guided-surgery has been completed) or made chairside using a wax-up to fabricate a crown using a bis-acryl material combined with a temporary abutment. If a temporary restoration is not available, then a healing cap/sulcus former can be placed. Sutures are then used to close around either prosthetic option, meaning a second surgical stage is avoided.
If the insertion torque of the implant is lower and primary stability is poor, or the clinician is inexperienced, then it is advisable to bury the implant by replacing the flap back to the original position using sutures. After three to six months (to allow for osseointegration and secondary stability to increase) the patient will then return, where the implant will be exposed, and a healing cap placed before proceeding with the restorative stages. At this stage, a small flap is raised over the implant. This is usually in the form of a H-shaped flap if adequate keratinised tissue is present. If there is a lack of keratinised tissue around the implant head then a roll-flap (see Figures 3-5) may be required to increase width, and this is then secured with sutures. If further soft tissue deficiency is present, then soft tissue augmentation in the form of a connective-tissue graft may be required. Once the hard and soft tissues have been assessed and are suitable, the clinician can proceed to the restorative stages.
Stage three: restorative stages
A multitude of restorative options are available for implants depending on the clinical need. As this article is focused on single implant restorations, I will concentrate on these options. Impression taking for implants is somewhat similar to that of traditional crown and bridge, with similar materials being available to use. In recent times, intraoral scans can be used for similar purposes. Intraoral photographs with shade tabs are essential at this stage to give the laboratory additional information:
1) Open tray impressions – the healing cap in situ is unscrewed and an open-tray impression coping is screwed into position – it is good practice to take a radiograph to confirm that the coping is fully seated onto the implant prior to impression being taken. A special tray, which is designed with an access hole over the implant position is then used with an appropriate impression material to record the dentition. Commonly a polyether (eg impregum) is used, making sure to apply Vaseline to the patient’s lip and surrounding oral tissues to allow ease of removal of excess impression material. Impression material is syringed around the coping and adjacent teeth prior to insertion of the special tray making sure to line up the coping post to the pre-cut hole in the tray. After adequate setting time, the coping post is unscrewed from the implant and the impression is removed. The healing cap is then replaced, and an alginate impression of the opposing arch is taken along with a bite registration
2) Closed tray impressions – the healing cap is unscrewed, and a closed tray impression coping is screwed onto the implant – it is good practice to take a radiograph to confirm that the coping is fully seated onto the implant prior to impression being taken. Impression material is again syringed around the impression post before the impression tray is inserted similar to a conventional crown/bridge impression. After adequate setting time, the tray is removed leaving the post in situ, which is then unscrewed and inserted accurately into the impression. The healing cap is then replaced, and an alginate impression of the opposing arch is taken along with a bite registration
3) Intraoral scans – the healing cap is unscrewed, and a scan body is inserted. An upper and lower arch scan is taken and a bite registration, which can be sent directly to the laboratory or exported to an STL file for use. A second scan is helpful with the scan body removed to capture the soft tissue around the implant with no post in place. The healing cap is then replaced.
Provisional implant restorations are often used to manipulate the soft tissue prior to the definitive restoration being fabricated. Often using a stock temporary abutment, they can be made chairside but on occasion lab-made temporaries are preferred. The use of intraoral scans and guided placement has now opened the doors to provisional restorations being fabricated prior to the implant surgery. This allows them to be placed simultaneously at the time of placement or onto the implant at the exposure appointment. This is obviously beneficial to the patient as it can reduce the time needed to wear a temporary removable prosthesis.
Once the soft tissue has been adjusted and a definitive restoration is required, the clinician has a choice of a cement- or screw-retained prosthesis. Screw-retained are now seen as the more sought-after restorative option, as they have the advantage of retrievability and ease of removal when issues occur. A small screw-access channel is positioned in the palatal cingulum region of anterior teeth, and the occlusal aspect of posteriors. The crown can be tried in situ when returned from the lab and assessed for shade match and occlusion, checking the patient is happy with the aesthetics. If so, then the crown is fully torqued to the manufacturers recommended torque for the implant used, and the small channel is then filled with composite.
For cement-retained restorations, the abutment is initially screwed onto the implant, using a jig to confirm the correct orientation, before a trial fit of the crown is completed. Once the patient confirms they are happy with the crown, the abutment is torqued into position and the crown is then cemented onto the abutment using a temporary cement (eg Tempbond). It is important that a radiograph is taken to check for any excess cement in the gingival sulcus region as this can lead to inflammation and peri-implantitis. It is also advisable to anaesthetise the area when fitting a cement-retained restoration to allow a probe to be passed around the prosthesis in the sulcus to remove any excess cement. Post-treatment radiographs can provide important baseline bone levels for future reference during assessments.
Stage four: maintenance
Maintenance of implant-retained prostheses and peri-implant tissues is essential for long-term success (Tarawali, 2015). It must be emphasised to the patient throughout the treatment that implants are not a ‘fit and forget’ and must be continually looked after. It is important that they routinely have their implants checked by a dental professional that has undergone adequate training in implant maintenance, whether that be their general dental practitioner or their dedicated implant surgeon.
Implant failures can be attributed to a number of causes such as poor prosthesis design, implant mobility, occlusal trauma, pain, infection and inflammation. Early failures can occur soon after placement when osseointegration fails to occur (Lindhe, Lang and Karring, 2012). Late failures occur post-osseointegration once the implant has been restored and are likely to be caused by disease/infection of the peri-implant tissues or biomechanical overload (Tarawali, 2015).
Patients who have completed implant treatment should be reviewed at least once a year, but ideally will see a hygienist every three-six months depending on their gingival health. It is important that the following checks are made at such appointments (Tarawali, 2015):
- Peri-implant soft tissue health
- Oral hygiene
- Bone levels (radiographs taken annually for first five years)
- Prosthetic assessment
- Changes to hygiene intervals needed?
Peri-implant mucositis and peri-implantitis
Peri-implant mucositis is a reversible inflammation of the mucosa surrounding implants where no bone loss has occurred. Peri-implantitis is an inflammatory reaction, which results in bone loss around an implant. When reviewing implants, the clinical signs that should be checked for are:
- Plaque/calculus formation
- Inflammation of peri-implant tissues
- Increased probing depths
- Bleeding on probing
- Presence of suppuration
- Implant mobility
- Radiographic changes
- Presence of increased probing depth compared to teeth is normal. Baseline probing depths should be recorded when definitive restorations are fitted for comparative purposes.
On fitting of a definitive implant restoration, baseline radiographs and probing depths should be recorded. Annual periapical radiographs should be taken for the first five years of function to assess any changes in bone levels around the implant. Data shows that most implants show marginal bone loss within the first year of function, but should not be progressive (Tarawali, 2015). The common causes of progressive bone loss are occlusal overload, biofilm-induced inflammation, inflammation due to excess cement presence or a combination of these.
Non-surgical treatment involves removal of plaque from the implant surface using ultrasonic scalers, air abrasion, lasers and use of locally-delivered antiseptics such as chlorhexidine gel. Adjunctive local or systemic antibiotics can also be used if deemed appropriate.
If over 2mm of progressive bone loss has occurred in conjunction with bleeding and suppuration on probing then surgical treatment may be required, similarly to periodontal treatment involving teeth.
Lifting a flap for direct access to clean and disinfect the implant prior to bone augmentation has been attempted with mixed results. Ongoing debates continue between clinicians whether it best to attempt GBR around a failing implant or remove the implant and replace. This decision should be made after discussing the options with the patient.
If you are concerned with the health of the peri-implant tissues, it is essential to refer the patient back to the surgeon who placed the implant in order for them to fully assess the problem and treat it accordingly.
As with all dental procedures, detailed history-taking and examination are key. Prior to any procedure being commenced, detailed discussions with the patient must be carried out in order for you to explain the treatment options that are applicable to them. In order to gain informed consent, all advantages and disadvantages should be discussed, with appropriate risks and benefits outlined, including associated costs. Once a treatment option has been chosen, appropriate planning is essential whether it involved dental implants or not.
In relation to dental implants, the patient must understand the stages of treatment and a rough timescale to complete the chosen plan. Appropriate training in the surgical and restorative aspects of implant dentistry are essential prior to any clinician embarking on treatment plans which involve implants, and knowledge in the important aspects of implant maintenance is also desirable to avoid future problems from occurring under your care.
Implants are a complex treatment of choice and inexperienced clinicians should aim to treat simple cases initially, such as single-tooth replacements, to gain valuable knowledge and skills before they embark on more complex treatment plans. Implants can be an extremely rewarding aspect of dentistry when performed correctly, with your patients benefiting greatly and making your work extremely enjoyable.
A 25-year-old female presented at the practice having pain and swelling from a previously root canal-treated lower left first molar. The patient was a regular attender at the practice, had good cooperation and an unremarkable medical history.
On presentation, there was suppuration from the buccal sulcus and increased localised pocketing around the LL6. The initial root canal had been replaced by a specialist endodontist two years previous, but again had failed and therefore the patient was seeking alternative options because they wanted something longer-lasting.
The patient had a moderately restored dentition, with stable gingival health and good oral hygiene. Radiographic assessment showed a large periapical radiolucency associated with the distal root, and a moderate periapical radiolucency associated with the mesial roots.
The patient was offered repeated RCT, or extraction and replacement with a partial denture, conventional fixed-fixed bridge or an implant. The patient wished to proceed with extraction of the problematic tooth and replace with an implant in due course.
Due to the presence of periapical pathology, we decided upon a staged approach for this patient.
The tooth was extracted atraumatically using a combination of luxators, elevators, periotomes and forceps, making sure to preserve as much of the surrounding bone as possible. Post-extraction, the socket was curettaged with gracey curettes and excavators to remove the granulation tissue.
Socket preservation was then carried out using allograft bone (Mineross Cancellous, Biohorizons) and a collagen plugged sutured in place to avoid loss of the granules. The patient was reviewed after two weeks to review healing and any remaining sutures were removed.
A sectional CBCT of the lower left mandible region was then carried out a further six weeks later to assess suitability for placement. Good boney infill of the root spaces was noted together with partial eradication of the previous periapical pathology. Adequate height and width of the ridge was maintained to allow for implant placement.
The chosen size of implant was a 4.6 x 9mm Biohorizons Tapered Internal as this maintained >2mm of bone surrounding the implant in all aspects, which is especially important over the inferior alveolar nerve.
The patient was booked in a further two weeks later for the placement to be completed.
Surgical placement of the implant was carried out around 10 weeks post-extraction. As explained previously, the size of implant required was planned using the CBCT software to allow ideal placement for optimal restorative purposes, whilst taking into account the current width and height of the ridge, maintaining an adequate safety margin above the inferior alveolar nerve. A crestal flap was raised without requiring any relieving incisions.
The osteotomy was prepared using the pilot drill to depth, before using the width increasing drills with stops in place to match to the planned depth. The slow drilling technique was used to collect bone particles during preparation.
The implant was firstly inserted at a torque of 35Ncm using the handpiece, before using the hand torque wrench to the planned depth. A post-op periapical radiograph was then taken to review the placement, before placing the bone particles collected back around the implant.
Sutures were then placed to close the flap and a review appointment was made for around two weeks after the procedure.
After around three months of healing time, the patient returned to expose the implant and place a healing cap. The soft tissue was reviewed for adequate keratinised tissue as this would determine what kind of small flap was raised.
As there was a good width of keratinised tissue a simple crestal incision could be used. A H-shaped flap was completed and reflected, and the implant cover screw noted. Some bone overgrowth had occurred over the implant and required removal under saline irrigation with a surgical bur.
The small cover screw was then removed, and a healing cap was placed to allow shaping of the sulcus. At this stage I would now take an ISQ reading but I did not have the required equipment for this.
The implant had no bone or soft tissue loss around it and had successfully osseointegrated, so we could proceed with the restorative stages after allowing the soft tissue to heal.
The patient returned for impressions to be taken at around two weeks post-exposure. The soft tissue had healed well as the patient had kept the area clean and healthy using a combination of chlorhexidine gel and toothbrushing.
The healing cap was then unscrewed and an open-tray impression coping was placed onto the implant and screwed into position. A radiograph was taken to confirm this was fully seated to avoid any errors in the impression.
The impression was then taken using Impregum in a special tray, with an opposing alginate impression and bite registration also taken. The healing cap was then replaced, and the impressions were sent to the laboratory together with shade matching photos for their reference.
We requested a screw-retained restoration as the access hole would be able to be positioned through the occlusal surface.
The patient then returned after two weeks where the restoration was screwed in situ and they were allowed to review the aesthetics.
As they were happy with the appearance, we torqued the crown in at 30Ncm, filled the screw access hole with medical grade PTFE tape, and placed a small composite to plug the access cavity.
Final occlusal checked were made, ensuring no working or non-working side interferences had been introduced.
The patient has routinely attended for six-monthly review and hygiene appointments over the past two years since the implant was restored. Annual periapical radiographs have been taken to assess bone levels, which remain consistent.
Jung RM, Rybak M, Milner P and Lewkowicz N (2017) Local anesthetics and advances in their administration – an overview. J Pre-Clinical Clin Res 11(1): 94–101
Lindhe J, Lang NP and Karring T (2012) Clinical Periodontology and Implant Dentistry, 2nd Volume – 5th Edition Wiley-Blackwell
Nicholson K (2016) Implant dentistry in general practice part 2: treatment planning. Dent Update 43(6): 522–8
Norton MR (2001) Single-tooth Implant-supported Restorations. Planning for an Aesthetic and Functional Solution. Dent Update 28(May): 170–5
Sethi S (2009) A Single Implant with Tissue Training in the Aesthetic Zone. Dent Update 36(6): 366–72
Tarawali K (2015) Maintenance and monitoring of dental implants in general dental practice. Dent Update 42(6): 513–8
Warreth A, Ibieyou N, Leary RBO, Cremonese M and Abdulrahim M (2017) Dental Implants : An Overview. Dent Update 44(August): 596–620
For referrals – Dentistry On The Square, 12 Niddrie Square, Glasgow G42 8QE.
Alternative email: Jamiekerr@dentistryonthesquare.co.uk
Course details – upcoming courses on ‘Restoring implants in general practice’ to be confirmed for September 2019.
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