Mr. Kameran Al- Naib

BDS, LDSRCS, MSc, FFDRCSI

Specialist Oral Surgeon

Numb Chin Syndrome

Sensory Neuropathy (altered sensation and numbness) in the distribution of mental or inferior alveolar nerve.

Anatomy

Presentation

• Intermittent pain• Progressive numbness• May lead to ulcer secondary to altered

sensation• It can associate with pain and swelling

Aetiology

• Dental Causes• Odontogenic• Dental abscess• Osteomyelitis• Benign tumours• Iatrogenic • Facial trauma• Wisdom teeth extraction• Sensory disruption after ID block injection• Orthognathic surgery• Implants• Mandibular surgeries• Orthodontic treatment• Pressure from dentures• Endodontic treatments

Systemic CausesAneurysmsAmyloidosisSickle cell anaemiaSyphilisSarcoidosisDemyelinating disorder (Multiple Sclerosis)Diabetes

• Malignant Causes of NCS• Head and Neck Cancers • Breast Cancer• Prostate cancer• Thyroid cancer• Lung Cancer• Renal Tumours• Melanoma• Multiple Myeloma• others

Diagnosis

• History of present compliant• Duration• Presentation• Any previous traumatic history• Any previous dental treatment• Medical history• others

Clinical examination

• Extra oral examination• Mapping the area of neuropathy• Light touch• Pressure• Cold sensation.• Pin prick• Lymph node enlargement.

Intra Oral Examination

• Mapping the area of altered sensation• Dental condition• Periodontal condition• Soft tissue• Hard tissue• Pin Prick• Touch sensation• Cold sensation

Investigations

• Radiological • A-Periapical• B- OPG• CT scan• MRI

Case 1

• 66 years old female• Presented with intermittent pain of lower left Canine

region of one week duration.• On examination, there was numbness of the affected

area and the Canine was TTP.• Radiological examination, OPG and Periapical

radiographs did not show any abnormalities• The patient was seen 2 weeks later and the area of

numbness increased.• Patient was referred to Neurology Department and was

diagnosed with metastatic renal cell carcinoma

Case 2• 55 years old female presented with 4 days history of inflammatory

lesion in LR3 with intermittent pain and numbness.• Extra oral examination the numbness extended to right infra orbital

region, and right submandibular region and mental nerve distribution.

• Intra oral examination, shows a ulcerated area of labial gingival opposite to LR3 .

• Radiological examination, periapical and OPT did not show any abnormality.

• Biopsy of the affected area confirmed the lesion to be inflammatory in origin.

• The patient was referred to Neurology Department• MRI examination revealed an intra cranial arteriovenous

malformation which was compressing on the trigeminal nerve root.• She was treated conservatively and the ulceration disappeared, the

numbness stayed but less frequent.

Ulceration

Case 3

• 40 years old female presented with one week of pain involving posterior left mandible and one day history of numbness in the left mental nerve.

• Extra oral examination revealed frank numbness in the distribution of mental nerve.

• Intra oral examination, dental condition was good however there was dental caries in the lower left wisdom tooth.

• Radiological examination, OPT confirmed periapical lesion associated with this tooth.

• Tooth was extracted and the numbness disappeared.

Case 3

Case 4

• 47 year old female presented with history of numbness affecting lower left lip for few months.

• Extra oral examination showed a well define area of numbness associated with distribution of mental nerve on the left side.

• Intra oral examination showed fractured cusps of lower left 6&7.

• Radiological examination, an OPT was taken and revealed an un-erupted and horizontally impacted wisdom tooth associated with a cystic lesion.

• The tooth and the cyst were removed, few weeks later the numbness disappeared.

Case 4

Case 5• A 57 year old patient presented with progressive

numbness of the right side of chin and lower lip. She had the numbness for four months.

• Medical history, she had history of breast cancer which was treated with radiotherapy and chemotherapy 3 years ago. She was on medication for hypertension, thyroxin and intravenous biphosphonates 3 monthly infusion.

• Intra oral examination showed a firm swelling in lower right second molar region with pus discharging, the adjacent teeth were not tender on percussion but were heavily restored.

• Radiological examination OPT, revealed a patchy radiolucent area associated with apices of lower right second premolar and second molar

Case 5

Case 5

• The teeth were extracted and the surrounded tissue and bone were biopsied the histopathology result did not show any secondary but a necrotic tissue.

• The patient was diagnosed with bacterial osteomylitis secondary to osteradio -necrosis.

Discussion