What percentage of the population is in class I occlusion?

  # What percentage of the population is in class I occlusion?

A. Less than 5 %

B. 25 %

C. 50 %

D. 70 %

The correct answer is D. 70 %.

Approximately 70% of the population is in class I occlusion. Approximately 25% of the population is in class II occlusion, and less than 5% of the population is in class III occlusion. 

Peri implant sulcular epithelium:

  # Peri implant sulcular epithelium:

A. Non keratinized

B. Both keratinized and non keratinized

C.  Attaches itself to smooth surface of neck profile of MIS (Mini implant screw) with hemidesmosomes

D. Serve as barrier for microbes

The correct answer is: A. Non keratinized.

After 3 months, all implants were firmly anchored in the bone and had no clinical signs of peri-implant inflammation. Undecalcified histologic sections demonstrated that all implants achieved osseointegration with direct bone contact. 

• The epithelial structures showed a peri-implant sulcus with a non-keratinized sulcular epithelium and a junctional epithelium. 

• Ultrastructural examination of the long junctional epithelial attachment adjacent to dental implants has demonstrated that epithelial cells attach with a basal lamina and hemidesmosomes. 

• Note that the intrasulcular tissue appears more erythematosus as the result of the thin, nonkeratinized layer of epithelium overlying the connective tissue. 

Correct treatment of a patient with ANUG is:

  # Correct treatment of a patient with ANUG is:

A. Amoxicillin 500 mg three times daily for 5 days and 0.2 % chlorhexidine mouthwashes twice daily 

B. Erythromycin 250 mg four times daily for 5 days and 0.2 % chlorhexidine mouthwashes twice daily 

C. Scaling and oral hygiene instruction 

D. Metronidazole 400 mg three times daily for 5 days and hydrogen peroxide mouthwash twice daily  

The correct answer is D. Metronidazole 400 mg three times daily for 5 days and hydrogen peroxide mouthwash twice daily. 

ANUG is a very painful condition. The most efficacious mouthwash is hydrogen peroxide, and the bacterial component is treated with metronidazole. Amoxicillin and erythromycin would be ineffective in the treatment of this condition. 

Inter transitional period is the period in which:

  # Inter transitional period is the period in which:

A. Permanent canine, premolar and molar erupt

B. Permanent molar has just erupted

C. 7-9 years of age with 12 primary and 12 permanent teeth

D. When all first molars are erupting

The correct answer is C. 7-9 years of age with 12 primary and 12 permanent teeth

Inter transitional period:

• Relatively stable phase 

• Teeth present are the permanent incisors and first molar (8 + 4 = 12) and deciduous canines and molars (4 + 8 = 12) 

Some of the features of this stage are: 

• Presence of Ugly duckling stage (7 to 9 years) 

• Root formation of emerged teeth + increase in alveolar process height 

• Root resorption of remaining deciduous molars 

• Preparatory phase for second transitional phase 

Class II division 2 features:

  # Class II division 2 features:

A. Maxillary centrals tipped palatally and in retruded position; maxillary lateral tipped labially and mesially 

B. Maxillary centrals tipped palatally and in retruded position; maxillary lateral tipped palatally 

C. Maxillary centrals tipped labially and in protruded position; maxillary lateral tipped labially and mesially 

D. Maxillary centrals tipped labially and in protruded position; maxillary lateral  tipped palatally 

The correct answer is A. Maxillary centrals tipped palatally and in retruded position; maxillary lateral tipped labially and mesially 

In class II division 2, it is typical for maxillary centrals to have linguoversion, whereas maxillary laterals are tipped in the labial mesial direction. Class II division 1 typically has maxillary centrals tipped labially and in a protruded position. Maxillary laterals are also tipped labially. 

All of the following are indications for removable appliances EXCEPT:

 # All of the following are indications for removable appliances EXCEPT:

A. Limited tipping movement

B. Retention after comprehensive treatment

C. Growth modification during mixed dentition

D. Close extraction spaces fully

The correct answer is D. Close extraction spaces fully.

Answer D is false because bodily tooth movement is required to close extraction space fully for which full orthodontic treatment with fixed appliances is necessary.

Which of the following is not true with regard to anterior open bites (AOBs)?

 # Which of the following is not true with regard to anterior open bites (AOBs)? 

A. Digit sucking is commonly associated with symmetrical AOB with associated posterior cross-bite 

B. An AOB of skeletal etiology is associated with an increased Frankfort-mandibular plane angle 

C. An AOB due to digit sucking can usually resolve spontaneously in the early mixed dentition stage 

D. An AOB in permanent dentition cannot be treated with orthodontics alone

The correct answer is A. Digit sucking is commonly associated with symmetrical AOB with associated posterior cross-bite

Digit sucking often presents with an asymmetrical AOB with associated posterior cross-bite. An AOB of skeletal etiology is when the vertical component of facial growth is disproportionally greater than the horizontal growth. The patient presents with a 'long face', with an increased lower anterior facial height, pronounced antegonial notching, retrognathic chin, and reduced interincisal angle. 

A symmetrical AOB may be associated with endogenous tongue thrust.  An AOB due to digit sucking usually resolves when the patient breaks the habit in the early mixed dentition stage, but if the habit is not broken by the late mixed dentition stage a deterrent appliance may be fitted. If an AOB is present in permanent dentition it is unlikely to resolve spontaneously.  In some cases, it is possible to close mild AOBs with the orthodontic intrusion of molars.