PULP SENSIBILITY AND MASSETER INHIBITORY REFLEX IN DIABETIC POLYNEUROPATHY

NCT07369297 | Not Yet Recruiting

• 1 other identifier: E.224974
• Study Type: observational
• Target: 108
• Locations: 0 countries
• Sites: N/A

Brief Summary

Accurate evaluation of dental pulp health is essential to avoid unnecessary endodontic treatments. In routine dental practice, pulp sensibility is commonly assessed using electric pulp testing and thermal (cold) testing. However, these tests depend on patient perception and may be influenced by various factors such as systemic diseases, nerve damage, anxiety, trauma, or medication use. Diabetic polyneuropathy is a common complication of diabetes mellitus and may alter peripheral nerve function, potentially affecting dental pulp sensibility test responses. This clinical study aims to evaluate how the severity of diabetic polyneuropathy influences dental pulp sensibility responses and masseter inhibitory reflex (MIR) parameters. The MIR is an objective neurophysiological reflex that allows quantitative assessment of trigeminal nerve function. In this study, individuals with mild diabetic polyneuropathy, severe diabetic polyneuropathy, and healthy controls will be evaluated. All participants will undergo electric pulp testing, cold testing, and MIR measurements using standardized protocols. The primary hypothesis of this study is that increasing severity of diabetic polyneuropathy leads to reduced dental pulp sensibility responses and altered MIR parameters compared to healthy individuals. It is further hypothesized that conventional pulp sensibility tests may produce false-negative results in patients with advanced neuropathy. The findings of this study are expected to contribute to more accurate endodontic diagnosis and improved understanding of orofacial neurophysiological changes in diabetic patients.

Conditions

Healthy Individuals (Controls); Diabetic Polyneuropathy

Keywords

Diabetic Polyneuropathy; Electrical Pulp Test; Cold Test; Masseter Inhibitory Reflex

Outcome Measures

Primary Outcomes (1)

• Electrical Pulp Testing Threshold

  Electric pulp sensibility will be evaluated using a standardized electric pulp test (EPT) performed on the maxillary central incisor. The tooth will be isolated and dried, and a conductive medium will be applied to ensure proper electrical contact. The EPT probe will be placed on the mid-facial surface of the tooth, and electrical stimulus intensity will be gradually increased according to the manufacturer's instructions. Participants will be instructed to indicate the first sensation perceived during stimulation. The stimulus will be stopped immediately upon participant response. The response threshold will be recorded as a numerical value on a standardized scale ranging from 0 to 64. The test will be repeated after a short recovery period if necessary to confirm reproducibility.

  The total duration of the EPT procedure is expected to be approximately 2-3 minutes per participant, including tooth isolation, probe placement, gradual increase of electrical stimulus intensity, and recording of the response threshold.

Secondary Outcomes (4)

• Time to First Sensation During Thermal (cold) Pulp Sensibility Test

  The thermal (cold) pulp sensibility test will require approximately 2-3 minutes, including tooth isolation, application of the cold stimulus, and recording of response times.

• Time to Disappearance of Sensation After Thermal (cold) Stimulus Removal

  The thermal (cold) pulp sensibility test will require approximately 2-3 minutes, including tooth isolation, application of the cold stimulus, and recording of response times.

• Masseter Inhibitory Reflex Latency

  The total duration of MIR recording, including electrode placement, calibration, and electromyographic data acquisition, is expected to be approximately 10-15 minutes per participant.

• Masseter Inhibitory Reflex Silent Period Duration

  The total duration of MIR recording, including electrode placement, calibration, and electromyographic data acquisition, is expected to be approximately 10-15 minutes per participant.

Study Arms (3)

Mild Diabetic Polyneuropathy

The severity of diabetic polyneuropathy will be determined based on nerve conduction studies performed by the Department of Neurology. Participants will be classified into mild or severe diabetic polyneuropathy groups according to standardized nerve conduction parameters, including sensory and motor nerve conduction velocities, amplitudes, and latencies. These classifications will be made by an experienced neurologist, and group allocation will be based on objective electrophysiological findings rather than subjective symptoms. Interventions will be performed in the following order: thermal (cold test), electric pulp test, and masseter inhibitory reflex recording.

Severe Diabetic Polyneuropathy

The severity of diabetic polyneuropathy will be determined based on nerve conduction studies performed by the Department of Neurology. Participants will be classified into mild or severe diabetic polyneuropathy groups according to standardized nerve conduction parameters, including sensory and motor nerve conduction velocities, amplitudes, and latencies. These classifications will be made by an experienced neurologist, and group allocation will be based on objective electrophysiological findings rather than subjective symptoms. Interventions will be performed in the following order: thermal (cold test), electric pulp test, and masseter inhibitory reflex recording.

Healthy Controls Group

The healthy control group will consist of individuals with no history of diabetes mellitus, peripheral neuropathy, or any other systemic or neurological disease. Control participants will have no history of chemotherapy, chronic pain disorders, or conditions known to affect peripheral nerve function. Individuals using medications that may influence sensory perception or nerve conduction within the last 24 hours will be excluded. Healthy controls will undergo the same standardized examination protocol as the diabetic polyneuropathy groups, including thermal (cold) testing, electric pulp testing, and masseter inhibitory reflex (MIR) recording, performed in the same fixed order. The same tooth selection criteria will be applied, and all procedures will be conducted under identical conditions to allow reliable comparison between groups.

Eligibility Criteria

• Age: 25 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Study participants will be selected from adult patients attending the Departments of Neurology and Endodontics at Bezmialem Vakif University. The study population will include individuals diagnosed with type 2 diabetes mellitus with mild and severe diabetic neuropathy who have been evaluated in the Neurology Department, as well as systemically healthy control subjects. Participants will be recruited from patients referred from the Neurology Department and from individuals presenting for routine dental examination at the university dental clinic.

You may qualify if:

• Ability to understand the study procedures and provide written informed consent.
• For diabetic polyneuropathy groups:
• Diagnosis of diabetic polyneuropathy confirmed by a neurologist
• Neuropathy severity (mild or severe) determined by nerve conduction studies
• For healthy control group:
• No history of diabetes mellitus
• No history of peripheral neuropathy or neurological disease
• Presence of at least one maxillary central incisor suitable for testing, defined as:
• No previous root canal treatment
• No extensive caries
• No clinical or radiographic signs of periapical pathology
• No periodontal disease affecting the selected tooth

You may not qualify if:

• History of chemotherapy, head and neck radiotherapy, or systemic conditions known to affect peripheral nerve function (other than diabetic polyneuropathy in the patient groups)
• Presence of acute or chronic orofacial pain disorders
• Use of medications within the last 24 hours that may affect sensory perception or nerve conduction (e.g., analgesics, sedatives, neuroactive drugs)
• History of trauma to the maxillary central incisor or surrounding tissues
• Extensive restorations, fractures, caries, or periodontal pathology involving the selected tooth
• Pregnancy or breastfeeding
• Inability to tolerate study procedures or refusal to continue participation at any point

Sponsors & Collaborators

• Bezmialem Vakif University: lead

MeSH Terms

Conditions

Diabetic Neuropathies

Condition Hierarchy (Ancestors)

Peripheral Nervous System Diseases; Neuromuscular Diseases; Nervous System Diseases; Diabetes Complications; Diabetes Mellitus; Endocrine System Diseases

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: January 7, 2026
• First Posted: January 27, 2026
• Study Start: January 15, 2026
• Primary Completion (Estimated): September 15, 2026
• Study Completion (Estimated): January 15, 2027
• Last Updated: January 27, 2026

Record last verified: 2026-01