Regressive changes in Tooth : Attrition, Abrasion, Erosion and Abfraction

Regressive alterations are the group of degradative changes in the teeth which occur due to non-bacterial causes and result in wear and tear of the tooth structure with some impairment of function. Let's see some of the commonest regressive alterations of teeth one by one.

Firstly, Attrition. Attrition is a form of regressive change in teeth characterized by wear of tooth substance or restoration as a result of the tooth to tooth contact during occlusion, mastication or parafunction. Mostly, attrition is an age-related physiological process whose rate and severity depends on several factors like diet quality, dentition, masticatory force and chewing habits. So, older individuals often exhibit more attrition than the younger ones.

Attrition may also  be pathological which may be caused either due to:
a. Abnormal occlusion - leading to traumatic contact during chewing which causes more tooth wear
b. Premature extraction of teeth - which causes attrition of remaining teeth as the occlusal load on these teeth increase after the extraction of teeth because the masticatory force of an individual remains constant.

Also, pathological attrition may be due to parafunctional chewing habits like bruxism and habitual chewing of coarse and abrasive foods or other substances like tobacco and betel nut.

Abrasion: It is the pathological wearing of tooth structure or dental restorations by friction with foreign substances independent of occlusion. Toothbrush abrasion is the commonest type of abrasion caused by faulty toothbrushing technique, excessive force during tooth brushing and a dentrifice with strong abrasive. Abrasion may also be caused by habitual chewing of betel nut. tobacco and Pan (betel quid), and also by faulty clasp design in removable partial denture prosthesis. Tailors, carpenters, hairdressers, and shoemakers who use their teeth to hold nails and pins also develop abrasion.

Erosion: It is the progressive irreversible loss of hard dental tissues by some chemical process that doesn't involve bacterial action. It may be caused due to extrinsic factors such as acidic foods and beverages, medications ( Vitamin C and Hydrochloric acid preparations) and occupational exposure to acidic vapors. Intrinsic factors causing erosions are systemic diseases like Bulimia, GERD (Gastroesophageal reflux disease), etc. which cause increased vomiting and regurgitation of bowel contents into the mouth.

Abfraction: It is the pathological loss of tooth structure caused by biochemical loading forces. Excessive force during chewing or clenching cause repeated flexure of tooth and cause ultimate material fatigue and wearing off of tooth away from the point of loading.

MCQs on Growth and Development - Orthodontics

# Growth site of the mandible is in the :

A. Body
B. Condylar cartilage
C. Coronoid process
D. Ramus

# Maxilla develops by :
A. Endochondral bone formation
B. Intramembranous bone formation
C. cartilage replacement and intramembranous bone formation
D. mostly cartilage replacement and a little by intramembranous

MCQs on Etiology of Malocclusion - Orthodontics

# Malocclusion can be progressive in:
A. Class I
B. Class II
C. Class III
D. Combination of both class I and Class III

# Retained mandibular deciduous central incisors will result in:
A. Lingual eruption of mandibular permanent incisors
B. Labial eruption of mandibular permanent incisors
C. Impaction of mandibular permanent incisors
D. Ankylosis of mandibular permanent incisors

MCQs on Development of Dentition - Orthodontics

# In children, median diastema between maxillary permanent incisors closes with the eruption of:
A. Maxillary permanent first premolars
B. Maxillary permanent lateral incisors
C. Maxillary permanent canines
D. Maxillary permanent second molars

# The average "Leeway space" available in each half of the maxilla is approximately:
A. 0.9 mm
B. 2.9 mm
C. 4.0 mm
D. 6.9 mm

MCQs on Child Psychology - Pedodontics

# Most realistic approach in managing a difficult child in dental clinic is:
A. Disregard the behavior of child
B. Make child familiar with clinical atmosphere
C. Physical methods to make child accept the treatment
D. None of the above

# Hand over mouth exercise (HOME) is effective behavioral modification technique in the age group of:
A. 3 to 6 years
B. Under 3 years
C. 6 to 9 years
D. Above 9 years

MCQs on Diseases of Blood - RBC Disorders, WBC disorders, Bleeding / Clotting Disorders

# All of the following statements about idiopathic thrombocytopenic purpura are true EXCEPT :
A. It is associated with platelet-specific auto-antibodies
B. It causes a prolonged bleeding time
C. It is often controllable by immunosuppressive treatment
D. It causes more prolonged hemorrhage than hemophilia

# The oral findings in erythroblastosis fetalis include:
A. Dentinal Dysplasia
B. Hypoplastic teeth
C. Pigmented teeth
D. All of the above

MCQs on Removable Partial Dentures : Introduction and Classification

# Class IV Kennedy classification is:
A. Bilateral edentulous area located posterior to the remaining natural teeth
B. Unilateral edentulous area located posterior to the remaining natural teeth
C. Unilateral edentulous area with natural teeth remaining both anterior and posterior to it
D. A single but bilateral (crossing the midline) edentulous area located anterior to the remaining natural teeth

# A distal extension partial denture receives its support :
A. From terminal abutments
B. Equally from abutments and the residual ridges
C. Mostly from residual ridge
D. Exclusively from residual ridge