The teeth most likely to be transposed are:

 # The teeth most likely to be transposed are:

A. Mandibular Premolars and maxillary incisors

B. Maxillary premolars and mandibular incisors

C.  Maxillary molars and canines

D. Mandibular molars and canines

The correct answer is B. Maxillary premolars and mandibular incisors.

Transposition is a rare positional interchange of two adjacent teeth. It occurs with a prevalence of approximately 0.3% and equally affects males and females. The teeth most likely to be transposed

are mandibular incisors and maxillary premolars, and this usually occurs as a consequence of ectopic eruption. There appears to be a genetic component to this problem. In the early mixed dentition years, transposition can develop when distally directed eruption of the permanent mandibular lateral incisor leads to loss of the primary mandibular canine and primary first molar. If left untreated, this can result in a true transposition of the permanent lateral incisor and canine.

The first material used for orthodontic TADs was:

 # The first material used for orthodontic TADs was:

A. Titanium

B. Stainless Steel 

C. Vitallium

D. Nickel - Chromium

The correct answer is C. Vitallium.

To date, three types of materials have been used for orthodontic TADs: titanium alloy, stainless steel

and vitallium. Vitallium was the first material used for orthodontic TADs. However, due to undesirable biocompatibility and a higher failure rate, vitallium was gradually replaced by titanium alloy. Stainless steel is also used for orthodontic mini-implants and recent evidence indicates that the success rate is similar between titanium alloy and stainless steel mini-implants. Nowadays, due to high biocompatibility of titanium, orthodontic TADs made of titanium alloy are most frequently used in clinical practice.

Reference: Clinical Insertion Techniques of Orthodontic Temporary Anchorage Devices, Wiley Blackwell

Who first advocated the opening of mid palatal suture to expand the dental arch?

 # Who first advocated the opening of mid palatal suture to expand the dental arch?

Emerson C. Angell 

B. Pierre Fauchard

C. Edward H. Angle 

D. Raymond Begg

The correct answer is A. Emerson C. Angell.

In 1860 Emerson C. Angell was probably the first person to advocate opening of the midline suture to provide space in the maxillary arch, because he took a very strong stand against extraction.

Ref: Graber, 7th Edition

Double lip is a feature of:

 # Double lip is a feature of:

 A. Aschers syndrome

B. Parry Romberg syndrome

C. Pierre Robin Syndrome

D. Mieschers syndrome

The correct answer is A. Aschers syndrome.

Ascher syndrome was first described in 1920 by an ophthalmologist. This syndrome presents as blepharochalasis(swelling of the eyelids), double lip and nontoxic thyroid enlargement. The thyroid enlargement is not present in all cases of this syndrome. The syndrome is often undiagnosed because of its rarity.