The participants were in complete agreement (100%) regarding the need for training in implant referral criteria, and 99% agreed PI should be taught at undergraduate level. It is well-understood that appropriate implant training can help in preventing and managing complications and medicolegal consequences.23 A review of post-graduate implant study in the UK revealed that there were eight courses that offered training to a Master's degree level and eight courses that offered a diploma-level training.24 The review identified 13 CPD courses, of which two were certificate-only courses that did not provide any verifiable CPD. All the Master's and diploma-level courses complied with the Faculty of General Dental Practice guidelines on Training standards in implant dentistry; however, the same could not be confirmed for the CPD-only courses.

In total, 85% stated that they did not have any training in PI in the undergraduate curriculum. Some of the perceived barriers to incorporating PI in the undergraduate curricula include training of suitable staff, recruitment of patients and increased costs.25 An earlier survey of UK and Irish dental schools in 2008 revealed that even though a high percentage of schools (87%) provided implant education to undergraduates, only 46% gained experience in treatment planning for implants and observation of implant restoration.26 This survey did not identify a specific clinical training being given to undergraduates for peri-implant diagnosis and management.

The General Dental Council (GDC) document Preparing for practice - dental team learning outcomes for registration specifies that the registrants must be able to give implant treatment options, explain risks and be competent at maintaining peri-implant health.27 The GDC advice for undergraduate curriculum states that dental students should be able to see dental implants being maintained in a healthy state in tissues.28 Without training in diagnosis of peri-implant disease, this learning outcome will be difficult to achieve for undergraduate students. The comments provided by respondents show that there is an urgent need for CPD courses that specifically train in preventing, diagnosing and providing treatment options for PI.

A total of 68.3% of the respondents did not have knowledge of the diagnostic criteria for PI, which may result in supervised neglect, or late referral and management. However, the majority of respondents (190) associate bleeding on probing with PI, which is one of the diagnostic criteria of peri-implant diseases; however, spot bleeding on probing can be due to probing causing minor trauma and alone is not indicative of disease. There was also a high number of responses to the other choices, especially correct probing depth (6 mm or more) and bone level (Fig. 1 - the correct answers are a, d and f).

GDP responses to diagnostic criteria for PI (a = presence of bleeding/suppuration on gentle probing; b = increased probing depth compared to previous examination; c = probing depth greater than or equal to 4 mm in the absence of previous examination data; d = probing depth greater than or equal to 6 mm in the absence of previous examination data; e = loosening of the abutment; f = bone loss of 3 mm or more from the neck [coronal margin] of the implant)

The survey also explored awareness of risk factors PI among GDPs (Table 6). Here, 94.2% selected periodontitis as one of the risk factors of PI. Poor oral hygiene was also selected as a risk factor by a high proportion of participants (94.6%). This shows that the participants are aware of the role of plaque in initiating this condition since plaque is an important aetiological risk factor. Smoking and uncontrolled diabetes were selected as risk factors by majority of participants (94.2% and 93.8%, respectively), although the evidence for these as risk factors is inconclusive.8 The Consensus report of the World Workshop on Periodontology and Implantology in 2017 set specific agreed diagnostic criteria and definitions of peri-implant diseases.8

Of the respondents, 77% agreed that they routinely refer patients if PI was suspected and 23% would not refer. The British Society of Periodontology and Implant Dentistry (BSP) has given guidelines regarding the referral pathway to be followed in PI patients.29 As per the BSP guidelines, peri-implant mucositis falls within Level 2 complexity and the advice is to treat it in general practice or to do a referral to specialist. PI however falls in the Level 3 complexity and BSP advices a referral after completing non-surgical treatment and addressing the risk factors in general practice. There need to be increased awareness that peri-implant disease can also be caused by the way the implant is restored. A study comparing association of restoration emergence angle and restoration profile with PI concluded that an emergence angle of >30 degrees is a significant risk factor for PI. This study also concluded convex profile is a risk factor for bone-level implants but not for tissue-level implants.30

This study elicited responses from a wide spectrum of GDPs in different regions and practice settings across the UK, which is one of the strengths. However, it may have limitations, such as sampling error and non-response error, as the study was released only on social media, which could have had an effect on the results.31