44. Protrusion (proclination). Clinical manifestation, diagnosis, prevention, treatment

Question 1

Protrusion and how it is categorized

Answer 1

• Forward positioning of jaws or teeth beyond normal limits=>
• Skeletal Protrusion (Prognathism)
• Dentoalveolar Protrusion

Question 2

Skeletal Protrusion (Prognathism)

Answer 2

• Bimaxillary Prognathism=>both jaws protrude forward beyond normal facial limits
• Maxillary Prognathism=>maxilla protrudes forward beyond normal facial limits
• Mandibular Prognathism=>mandible protrudes forward beyond normal facial limits

Question 3

Dentoalveolar Protrusion

Answer 3

• Bimaxillary Dentoalveolar Protrusion=> Anterior teeth of both jaws forward of normal limits of basal bone
• Maxillary Dentoalveolar Protrusion=>Maxillary anterior teeth forward of normal limits of basal bone
• Mandibular Dentoalveolar Protrusion=> Mandibular anterior teeth forward of normal limits of basal bone

Question 4

Etiological factors of protrusion

Answer 4

• Genetic causes
• Injuries
• Cleft lip and palate
• Supernumerary teeth=> misalignment
• Oral habits=>digit sucking and tongue thrusting
• Premature loss of primary teeth=> movement of permanent teeth
• Underlying causes

Question 5

Types of injuries causing protrusion

Answer 5

• Fetal molding and trauma during birth (e.g., from forceps use).
• Injuries throughout life=>
• Trauma to permanent tooth buds
• Premature loss of primary teeth=>movement of permanent teeth
• Direct injury to permanent teeth

Question 6

Underlying/genetic causes resulting in protrusion

Answer 6

• Acromegaly=>Hormonal disorder causing abnormal growth of bones
• Basal cell nevus syndrome=> Genetic condition affecting bone development
• Acrodysostosis=>Genetic disorder affecting skeletal development

Question 7

Clinical manifestations of protrusion

Answer 7

• Extraoral features
• Intraoral features

Question 8

Extraoral clinical features of protrusion

Answer 8

• Bimaxillary protrusion=>
• Decreased nasolabial angle=> proclined maxillary anterior teeth
• Shallow mentolabial sulcus=> proclined mandibular anterior teeth
• Incompetent lips
• Convex facial profile
• Mandibular protrusion=>
• True progenia=>Prominent chin and positive lip step
• Pseudo progenia=> Flat midface and hypotonic upper lip

Question 9

Intraoral clinical features of protrusion

Answer 9

• Bimaxillary protrusion=>
• Maxillary and mandibular anterior proclination
• Class I molar relationship
• Class I canine relationship
• Possible spacing between teeth
• Mandibular protrusion=>
• Small upper alveolar process and prominent lower alveolar process
• Crowding in upper jaw and spacing in lower jaw
• Lower tongue posture
• Mesioocclusion (class III malocclusion)

Question 10

How protrusion diagnosed

Answer 10

• Anamnesis=>Detailed patient history
• Clinical examination=>
• Eschler-Bittner test (Class II test).
• Class III test
• Dental model analysis=>
• Lo and Lu assessment
• Tooth malposition and inclination analysis
• Radiographic examination

Question 11

Radiographic examination of protrusion

Answer 11

• Cephalometric findings=>
• Bimaxillary protrusion=>
• Decreased interincisal angle
• Increased incisor mandibular plane angle, increased SNA and SNB if prognathism of jaws
• Maxillary prognathism=>varying combinations of SNA and SNB values
• Mandibular prognathism=>normal SNA and increased SNB, or decreased SNA and normal SNB
• Dentoalveolar protrusion=> Increased values of angles related to maxillary and mandibular incisor axes to various planes
• OPG (Orthopantomogram) findings=>
• Mandibular protrusion=>upper jaw tooth buds close together, lower jaw tooth buds far apart

Question 12

Preventive measures for protrusion

Answer 12

• Address genetic and environmental factors early=>
• Managing oral habits=>thumb sucking and tongue thrusting
• Monitoring and addressing early signs of dental anomalies
• Regular dental check-ups=>prevent injuries and manage primary teeth loss

Question 13

Treatment options for protrusion

Answer 13

• Extraction of all first premolars=>create space for alignment
• Treatment based on canine angulation=>
• Distally inclined canines=>retract and align incisors using retainer
• Mesially inclined canines=>fixed appliances
• Surgical intervention for setting back prognathic jaw
• Mouth guard for managing dentoalveolar protrusion