Complete denture series part 1: referrals for complete dentures – identifying the reasons

Resorption of lower ridge

The main reason for referral was advanced resorption of the mandibular alveolar ridge. The ridge classification described by Atwood⁸ is used in this article (Figure 1).

Whilst practitioners did not mention any actual ridge classifications, it was evident from the letters and the subsequent examination that Ridge Classification V – flat ridge form, inadequate in height and width and Classification VI – depressed ridge form, with some basal bone loss, are of main concern. Mandibular bone loss was mentioned in 39% of the letters (amounting to 28 out of 71 letters). This corresponds to the findings from the New Patient Assessments, where 44% of the patients were diagnosed with resorption pattern V or VI. However, it is of note that the examining clinician on a few occasions did not agree with the assessment of the GDP and diagnosed a ridge Classification III, where the letter of referral read ‘atrophic upper and lower ridge’ or ‘loss of mandibular and maxillary bone’.

Several letters revealed that no attempt was made to construct dentures locally as some GDPs did not find that these cases were suitable for primary care.

Looseness

Advanced resorption and looseness were two factors that GDPs felt were associated and frequently mentioned in the same letter. Looseness was reported in 18 letters, which corresponds to 25% of the letters. Looseness of dentures is a relative concept. In denture literature, looseness could be caused by lack of retention, instability and/or issues with support.⁹ Six letters of referral mentioned that a reline had been carried out to improve on retention but failed.

Looseness can be caused by:

From the above, it is evident that a reline will not always resolve the problem of ‘looseness’, especially if there is an occlusal error.

Pain

Pain was the third most common reason to refer patients to secondary care and was mentioned in 8 letters (11% of letters). Painful dentures may be due to anatomical features, poor adaptation to the denture-bearing area and over extensions.

It will not come as a surprise that there seemed to be an association between pain and ridge classification. The attached oral mucosa is bound to bone and therefore more able to withstand compressive forces. Resorption of the alveolar ridge leads to a reduction in the denture-bearing area and therefore the surface of attached and unattached mucosa decreases significantly for ridges Class III to Class VI.¹⁶ The pressure applied during function on this reduced denture-bearing area can lead to pain and discomfort.¹⁵ It has also been reported in the literature that patients with a reduced ridge height are more likely to complain of sore gums.¹⁷

Immediate dentures and exaggerated gag reflex

Immediate dentures and an exaggerated gag reflex were combined under one title as it was noted in several letters of referral that patients who were found struggling with immediate dentures also suffered from an exaggerated gag reflex. This is in agreement with the study of Jonkman et al,¹⁸ which established that 9% of patients who were dissatisfied with their immediate dentures complained about lack of retention of the maxillary denture. Several authors suggest that unretentive upper dentures will induce gagging when the dentures are fitted.^{19, 20}

Of the five patients referred for an exaggerated gag reflex, only one patient was suspected of having a psychogenic component which was considered to require management in a non-dental setting before constructing new dentures. For the remaining patients, the main treatment approach was to construct well-fitting dentures. Some patients benefit from the construction of training plates as an intermediate measure or would benefit from modified designs, but this will not be discussed as it is out of the scope of this paper.

Implants

The heading ‘implants’ includes all letters of referral where patients requested implants and patients who were in need of replacement implant-retained overdentures. The McGill and York consensus statements suggest that a two-implant overdenture should become the first choice of treatment for the edentulous mandible.^{21, 22} This has been supported by a review of the literature by Thomason et al. Their conclusion was that two mandibular implants should be the minimum standard for most edentulous patients taking patient satisfaction, cost and clinical time into consideration.²³ However, a systematic review by Fitzpatrick concluded that there is no evidence for a single universally superior treatment for edentulous patients. He states that educational background, knowledge, experience of a dental healthcare provider, socio-economic, regional, cultural, age and gender factors play a major role in what would be the most optimal treatment modality.²⁴

It is noted that requests for implant placement seemed to be mainly instigated by individual patients who have read magazine articles, watched reality television shows, or did their own research on the internet.

Other

In the group ‘other’ the reasons for referral were ill-defined problems, eg patient unable to adjust to any dentures, dentures are rubbing, patient unhappy with fit, patient unable to tolerate any dentures, patient unable to masticate, patient unable to eat salad and slices of apple, etc. It is remarkable that the letters of referral did not contain any prosthodontic terminology. Clinically, a multitude of errors were diagnosed within the denture sets. The denture problems ranged from under/over extensions, instability, the teeth positioned out of the neutral zone, to errors with the jaw relationship and the occlusal vertical dimension.

Besides the above reasons, in a few letters, a distinctive Class III was mentioned but a Class II was never mentioned as a complicating factor. Similarly, during the New Patient Assessments, five patients were diagnosed with a distinct Class III jaw relationship but no mention was made of patients having a severe Class II. Patients with a severe Class II or Class III jaw relationship require careful planning.²⁵ A common error is that dentures are made to achieve a Class I tooth set-up. Inevitably, these dentures lack stability (see above). For patients with a skeletal Class II, the lower denture teeth are often positioned too far forward, namely in the anterior buccal sulcus, where they interfere with the circumoral musculature. For patients with a skeletal Class III, the upper teeth are often positioned too far forward and there is generally a lack of posterior contacts.