Huntington’s disease (HD) is a rare genetic neurodegenerative disease which causes progressive motor impairment leading to chorea, cognitive decline and behavioural issues in affected individuals. Currently, treatment is aimed at managing symptoms and improving patients’ quality of life, however, research is ongoing to develop curative treatments. The oral manifestations of HD have been documented in the literature and include dysphagia, bruxism, speech disorders and uncoordinated movements of the maxillomandibular region. These manifestations present challenges in the maintenance of oral hygiene and in the delivery of dental care.

The aim of this systematic review was to provide a complete overview of the oral manifestations of HD.

Methods

The PRISMA checklist was followed in this systematic review and searches were conducted in five electronic databases (PubMed Central, Embase, Cochrane Central Register of Controlled Trials, Scopus and Web of Science). There were no language restrictions on publications and manual searches were not performed. Two reviewers screened the titles and abstracts of the studies and a third reviewer confirmed that the studies were eligible. Any disagreements between the reviewers were resolved by discussion. When a decision could not be reached, the collaborators were consulted. Research articles and case reports involving patients diagnosed with HD were included. Data was assessed using Rayyan with blind mode (to avoid selection bias). The Joanna Briggs  risk of bias assessment model was applied and the most experienced reviewers also performed bias assessments.

Results

• In total, 22 studies were used (12 research articles and 10 case reports) from 1992-2021
• Of the 12 research articles; 2 were observational cohort studies, 8 were case controlled studies and 2 were cross sectional studies.
• The research articles included patients at different stages of HD (including premanifest, early, mild, advanced and juvenile).
• Different HD classifications were used in the studies: 9 used the Unified Huntington’s disease rating scale (UHDRS), 3 used the total functional capability scale (TFC), 4 used the Mini-Mental State examination (mMMSE), 1 used the burden of pathology score (BoP) and 2 used Shoulson & Fahn..
• The prevalence of impairment as a result of HD was described in the studies:
  • Dysphagia/swallowing impairment: prevalence was observed in 6 studies, ranging from 32.4% to 77.6% of HD patients..
  • Dysarthria/speech impairment and/or speech comprehension: 5 studies observed this. One study observed a significant moderate correlation between the expressive component of speech and language competency using the Hooper Visual Organisation Test (r=0.519 and r=0.450 respectively).
  • Oral health status: 6 papers observed this. One paper observed a significant negative correlation between functional capacity score and plaque score (r=-0.501) and a positive correlation between the number of missing teeth and psychiatric onset of the disease (r=0.416).
  • Muscular orofacial activity: 4 studies observed this. One study observed a strong correlation between tongue contact time and HD genotype and another study observed that submental muscle activity during expiratory muscle training in HD patients was at 75% compared with the control group.
  • Dysphagia and dysarthria was observed in one study.
• Seven case reports did not include the patient’s stage of HD, which was considered essential in the assessment of bias.
• The research articles had good overall bias assessment scores, given the rarity of the disease.

Conclusions

The authors concluded: –

Multidisciplinary cooperation between neurologists and dentists or oral medicine specialists is critical. Referral to a dental practice and regular check-ups of patients in the early stages of HD will improve such patients’ oral health and quality of life. A visit to the dentist or oral medicine specialist should be part of the HD protocol.

Comments

As HD progresses, motor and cognitive symptoms worsen and can present challenges for the dental team. Later challenges include issues with denture construction and retention (which is often worsened by the xerostomic effects of antipsychotic medication) and even simple dental examination and treatment may be compromised due to choreiform movements of the head and tongue. Cognitive impairment in HD present challenges in communication with the patient, as well as issues with capacity and consent. Treatment should be aimed at early prevention of dental disease to avoid challenges in the later stages of the disease. Support should be given to the patient and care staff to carry out effective oral hygiene throughout the course of HD.

Links

Primary paper

Review protocol in PROSPERO 

Other references

Dental Elf – 6^th November 2017

Dementia and oral health status

Photo credits

Photo by Diana Polekhina on Unsplash