Introduction

Implant-based treatment may be provided within restorative dentistry departments in the secondary NHS care setting in certain situations, such as loss of teeth due to orofacial trauma or ablative surgery for head and neck cancer, missing teeth due to congenital or acquired defects for example, hypodontia and cleft palate, or difficulties with complete dentures. Funding for this treatment is limited, and acceptance criteria are determined locally according to funding agreements with NHS England. Treatment is not generally available within hospital restorative dentistry departments in relation to implant treatment either started or provided elsewhere, be it for completion of treatment, comprehensive management of complications or prosthodontic or peri-implant maintenance. However, patients may be provided with the treatment required to alleviate pain or infection for patients provided with treatment elsewhere, for example by removing implants associated with repeated infections.

Implants may be restored with either fixed crown and bridgework, or with removable overdentures. Fixed prostheses may be either screw- or cement-retained (Fig. 1). Definitive implant-retained crowns or bridges may be constructed using a substructure (for example, titanium, cobalt-chromium, zirconia) and veneering porcelain or acrylic. Abutments for cement-retained crowns may be constructed in metal or zirconia. Once the abutment or prosthesis is screwed in place, the screw head is usually protected by a material, for example, cotton wool or PTFE tape followed by a restorative material, for example, composite. Overdentures may be retained with either bars or individual magnetic, ball-ended or locator attachments (Fig. 2).

Figure 1: (a) Diagrams representing the components of a screw-retained crown; (b) Diagrams representing the components of a cement-retained crown; (c) Occlusal view of screw-retained single crown replacing the 21.
figure 1

Note composite restoration in the palatal screw access hole

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Figure 2
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(a) Locator abutments in situ; (b) Lower implant-retained overdenture with locator housings and blue-coloured retentive inserts

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Ongoing clinical and radiographic review of implant cases is essential to monitor the peri-implant tissues and the prostheses, however, indefinite review of all patients in secondary care is unlikely to be feasible due to limitations on departmental capacity. Patients are therefore discharged to their general dental practitioner (GDP) following completion of treatment. Over time, complications may arise, affecting either the implants themselves, the prostheses or the peri-implant soft and hard tissue. Common prosthetic or technical complications are listed in Table 1.1,2

Table 1 Common technical and prosthetic complications affecting implant-retained prostheses
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The increasing number of patients provided with implant-based treatment in secondary care has resulted in a growing maintenance burden, raising the question of who should provide this care. Management of complications obviously varies in complexity, but a number of issues are straightforward to manage with appropriate training, for example replacement of worn overdenture inserts or replacement of restorations lost from the screw access holes of fixed restorations.

When complications arise, re-referral of the patient to the restorative dentistry department at which they were initially treated may not be convenient for them. There may be a significant waiting list before assessment and treatment, or they may need to travel long distances, particularly if they have moved away from the area in which treatment was provided. Management of some complications within primary care would facilitate patients' access to treatment, however, no specific provision for maintenance of implant-retained prostheses is made within the NHS Dental Charges Regulations.3

The advice from the NHS Business Service Authority is shown in Box 1.4 It mentions 'cleaning and polishing' and also makes reference to 'long term maintenance', which could be interpreted broadly to include repair to crowns, bridges or overdentures retained by implants. The suggestion is that to provide this type of care, GDPs should seek a 'one-off' agreement on a case-by-case basis from the NHS Local Area Team. As the availability of such 'one-off' agreements varies locally,5 it is unclear as to what treatment can be provided within NHS general dental practice.

A survey was carried out to review services provided within restorative dentistry departments in secondary care across the UK. The aims were to assess departmental protocols for review, discharge and provision of maintenance treatment for patients provided with dental implants. Information was gathered regarding the frequency of review following implant placement, length of review period before discharge, and management provided for complications affecting those implants or restorations provided within the respective departments.

Methods

An online survey was developed by the authors using the Survey Monkey website (www.surveymonkey.net). This survey (Appendix 1) was open for responses between 20 April and 26 May 2016. Restorative Dentistry-UK (RD-UK) is a group of consultants and specialists in restorative dentistry. A covering letter and invitation to participate was sent via email to all members on the RD-UK mailing list, followed by a reminder email two weeks later. All responses were anonymous, and questions regarding the participant's job title and unit in which they work were optional.

Results

One hundred and twenty-five RD-UK members were invited to participate in the survey, and 37 responses were obtained (30% response rate). Of 33 participants who provided their job title, there were 29 consultants in restorative dentistry, three professors/honourary consultants in restorative dentistry, one professor in periodontology and one senior lecturer/honourary consultant in restorative dentistry. Twenty-two participants from 17 units gave their place of work.

Eighty-nine percent (33/37) of respondents were involved in the placement and/or restoration of dental implants. Of these, 70% placed and restored dental implants, whereas 30% only restored implants. Not all respondents answered every question; those with free text responses were not mandatory.

Review protocols

Free-text responses were invited regarding review protocols following completion of treatment. Not all respondents provided answers to these questions. There was significant variation in the responses, although 80% (24/30 respondents) reported carrying out initial review between 1-3 months following definitive restoration with crown/bridgework. Following an initial period of more frequent short-term review 40% (12/30 respondents) then reviewed patients annually for a variable time period before eventual discharge (Fig. 3).

Figure 3
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Review period before discharge

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The length of the review period before discharge varied but was most often done at 1-3 years following definitive restoration. Responses were similar for patients provided with overdentures. Seven percent (two respondents) provided indefinite annual review, and 3% (one respondent) arranged indefinite 6-12 monthly reviews with a hygienist only. Of those respondents carrying out radiographic review (26 respondents), 48% (12 respondents) would do so annually; 4% (one respondent) every six months; 15% (four respondents) biannually and 35% (nine respondents) only if problems arose. A number of free text comments indicated that the review period would vary according to various patient-related factors, with longer review periods for oncology patients (five responses) or in the presence of complications or symptoms (ten responses) in particular.

Maintenance of restorations (including on a re-referral basis)

Implant-retained overdentures

Twenty-nine percent (8/28 respondents) indicated that they would not provide maintenance of implant-retained overdentures, advising patients to seek maintenance within primary care (Fig. 4). Fifty-seven percent (16/28 respondents) would indefinitely carry out remake of implant-retained overdentures when clinically indicated, replace worn inserts, housings or abutments. Fifty percent (14/28 respondents) would repair fractures of acrylic. Eight free-text comments suggested that GDPs were often unwilling or unable to provide this type of treatment, so there was no option but to accept the patients for treatment.

Figure 4
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Percentage of respondents carrying out maintenance of implant-retained overdentures

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Implant-retained crown and bridgework

Similar responses were given for acceptance of patients requiring maintenance of implant-retained crown and bridgework (Fig. 5); 61% (17/28 responses) would manage loose/lost screw- or cement-retained restorations and 68% (19/28 responses) would manage fractured restorations.

Figure 5
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Percentage of respondents carrying out maintenance of fixed implant-retained crown or bridgework

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Only 46% (13/28 responses) would accept re-referral for management of restorations lost from screw access holes, and free-text comments suggested that this was expected to be managed within primary care.

Fourteen percent (4/28 responses) would not accept any re-referrals for maintenance of implant-retained crown or bridgework.

Management of peri-implantitis

Again, questions regarding acceptance of re-referrals for peri-implantitis related specifically to those patients who had been provided with their implant treatment within the department. In the absence of peri-implantitis, 76% of responders would not provide any ongoing peri-implant supportive therapy.

In a question asking whether re-referral would be accepted for peri-implant disease, 64% (18/28 responses) indicated that they would do so. However, in a separate question inviting free-text responses as to whether peri-implant supportive therapy would be provided for implants placed within the department, 71% (20/28 comments) indicated that at least one course of treatment would be provided in at least some cases, which may be followed by discharge back to the GDP following stabilisation by 14% (4/28 comments). The reason for this disparity in responses to the two questions is not clear.

Other concerns raised

Respondents were invited to express any other opinions related to the long-term review and maintenance of patients provided with implant-based treatment. The following concerns were expressed:

  • Lack of guidance/criteria for:

  • Service providers' responsibility for maintenance of implants and implant-retained restorations

  • What treatment should be provided within primary care

  • Management of patients experiencing problems with treatment provided within the private sector

  • The need to discharge patients from secondary care to create capacity to manage new patients, contrasting with the need for maintenance care to be available

  • Difficulties in maintenance associated with the range of implant systems in existence, and particularly with patients' lack of knowledge as to the type of implants with which they have been provided

  • Need for clarity of patient information and consent at the outset as to who will provide maintenance in future, and that this may need to be sought in the private sector

  • The need for development of funding and skills in primary care.

Discussion

The questions in the survey were developed following discussion among the authors, and piloted within the department to check for errors. A wider pilot was not deemed feasible as the authors did not have access to the target mailing list; the invitation to the survey was disseminated by RD-UK on behalf of the authors.

The response rate was relatively low (30%). However, online survey response rates may be on average only around 40%.6 There was no specific database of those RD-UK members involved in implant-based treatment, so the invitation was sent to a broad range of consultants and specialists in practice and in secondary care. As such, since the covering letter with the email invitation explained that the survey was related to the provision of implant-related treatment, specialists or consultants not involved in implant treatment, or not working in secondary care, may likely have opted not to participate. The response rate therefore probably appears artificially low relative to the responses from the 'target' population (that is, providers of implant treatment in secondary care). Only four respondents (11%) were not involved in either the restoration or placement of dental implants, and therefore did not complete the remainder of the survey.

Frequency of clinical and radiographic review

There is no consensus within the literature as to the recommended frequency of clinical review following implant placement. This is reflected in the responses from this survey, with a variety of review protocols described. Recall intervals will often be modified by patient factors (for example, risk factors, type and complexity of treatment provided, levels of oral hygiene, presence of complications), but in general, more frequent review is advocated in the first year following restoration of implants, followed by 6-12 monthly review in the absence of complications.7,8Patients provided with implant treatment in secondary care would likely also be under routine review from their own GDP.

A 2004 Consensus statement by Lang et al. recommended that while it is 'appropriate' to take a radiograph at the time of placement of a prosthesis, repeated radiography should be based on clinical assessment rather than pre-determined protocols.9 Other published guidance recommends radiographic examination; at fit of prosthesis,7,10 one year later,7,11 then biannually7,11 or if signs or symptoms should arise.7,10,11

Provision of ongoing maintenance

An increasing number of patients are being provided with implant-based treatment. Limitations on departmental capacity mean that it is unlikely to be feasible for all patients provided with implant-based treatment to be seen indefinitely for review. Most (26/30) respondents to this survey would discharge patients back to their GDP within five years of treatment completion.

Eighty-six per cent (25/29 respondents) of respondents would accept re-referrals for maintenance of implant-retained crown/bridgework, 57% (17/29 respondents) would accept re-referrals for maintenance of implant-retained overdentures, and 64% (19/29 respondents) would accept re-referrals for peri-implantitis. Around a third of respondents would encourage the patient's GDP to provide the maintenance, but it was often acknowledged that GDPs may be reluctant to carry out this treatment. Responses from a number of restorative dentistry departments indicated that they are unable to provide ongoing repair and maintenance work due to restrictions on funding.

Adoption of a shared care approach between primary and secondary care would be beneficial. Management of appropriate complications within primary care would facilitate patients' access to treatment. The attitude of GDPs with regards to maintenance of implant overdentures using the locator system was investigated in a 2014 survey, which found that only 17% of GDPs were involved in the placement or restoration of dental implants.12 Similarly, a 2009 survey found that 20% of GDPs would 'always' or 'sometimes' provide some of the treatment involved in a mandibular implant-supported overdenture.13 Few GDPs were prepared to carry out maintenance such as replacement of overdenture inserts or tightening of abutments.12 Fifty percent of GDPs felt that they should not be responsible for maintenance of implant overdentures, with most feeling that this should be provided within secondary care. The most common reasons given were insufficient time, remuneration, lack of training and equipment. Indeed, 74% of GDPs have indicated that they would like further training in the management of prosthodontic complications of implant-retained overdentures.12 The attitude of GDPs towards fixed implant-retained restorations has not been investigated, but is likely to be similar.

Training for GDPs who refer patients for implant-based treatment would enable management of some complications within primary care, facilitating patients' access to treatment. This could be could be part of a managed clinical network, or could be offered via local courses, for example, through local education and training boards (LETBs), and could be delivered by secondary care providers.

Funding arrangements for the ongoing care of implant-retained restorations within the NHS is not clear, and lack of NHS funding appears to be a significant barrier to the ongoing management of implant cases in both primary and secondary care.

There is a need for identification of appropriate care providers, and development of a system through which maintenance care can be provided. This could potentially be achieved through adding implant-related maintenance treatments to the NHS Dental Charges Regulations for primary dental care, and/or clarification of secondary care funding agreements for ongoing treatment. It may be that secondary care providers should assist the GDP to gain a 'one-off agreement' from the local area team, enabling them to provide at least peri-implant maintenance therapy. As access to these agreements is variable, patients should perhaps be informed that they may need to seek future ongoing maintenance treatment on a private basis.

Conclusions

There was no consensus view among the respondents to this survey on review protocols, discharge or provision of maintenance following implant placement.

As time goes on, more patients are being provided with implant-based treatment, therefore, more patients will require treatment for associated complications. There is no clear funding for the management of these complications within either primary or secondary care, and this was of concern to respondents in this survey. The lack of funding and, therefore, availability of this treatment may potentially affect the long term success and efficacy of the implants and implant-retained restorations, which would have been provided to patients already in priority groups to have qualified for implant treatment under the NHS in the first instance.