Effectiveness of Acclimatization or Desensitization in The Effective Dental Management of Patients With Learning Disabilities: A Systematic Review

Abstract

Background. People with learning disabilities experience worse oral health and greater unmet treatment need than the general population, yet a substantial proportion of their dental care is still delivered under sedation, general anaesthesia or physical restraint. Acclimatization and desensitization the graded, repeated exposure of a patient to the dental environment, personnel and instruments are widely advocated as a means of enabling care without pharmacological escalation, but the strength of the evidence supporting them has not been formally appraised.

Objectives. To determine whether acclimatization or desensitization techniques improve cooperation, reduce dental anxiety, or increase treatment completion in patients with learning disabilities undergoing dental procedures, compared with standard care or alternative behaviour-support approaches.

Methods. The review was prospectively registered (PROSPERO CRD420261397288) and reported in accordance with PRISMA 2020. Electronic databases and registers were searched alongside citation searching and targeted website searching. Records were screened in duplicate against pre-specified PICOS criteria. Data were extracted onto a piloted form, risk of bias was appraised using the domains of the Cochrane risk-of-bias framework, and findings were synthesised narratively following SWiM guidance because clinical and methodological heterogeneity precluded meta-analysis. Certainty of evidence was rated using GRADE.

Results. Of 618 records identified, six met the eligibility criteria. The evidence base comprised predominantly synthesised evidence and reported on more than 1,250 individually enumerated participants across paediatric, adult and older-adult populations with autism spectrum disorder and intellectual or developmental disability. Four studies were judged at low overall risk of bias, one raised some concerns and one was at high risk. Acclimatization and desensitization delivered as visual pedagogy, video modelling, tell-show-do and sensory-adapted exposure were consistently associated with improved cooperation and reduced procedural anxiety, although effect estimates were rarely poolable and definitions of the intervention were highly inconsistent. Where non-pharmacological preparation failed or was not attempted, conscious sedation achieved success rates commonly exceeding 80%, with nitrous oxide–oxygen the most efficient single agent. No included study demonstrated that acclimatization reliably averted the need for pharmacological support in patients with severe or profound disability.

Conclusions. Acclimatization and desensitization are supported by low-certainty evidence for improving cooperation and reducing anxiety, and are reasonable first-line strategies in patients with mild to moderate learning disability. The evidence is too heterogeneous and too poorly standardised to support firm recommendations on protocol, dose or patient selection. Adequately powered trials using an agreed intervention taxonomy and core outcome set are the priority.