Grossly decayed mandibular molar removal

# While attempting to remove a grossly decayed mandibular molar, the crown fractures. What is the recommended next step in order to facilitate the removal of this tooth?
A. Use a larger forceps and luxate remaining portion of tooth to the lingual
B.  Separate the roots
C.  Irrigate the area and proceed to remove the rest of the tooth
D. Place a sedative filling and reschedule patient

The correct answer is B. Separate the roots.

This can be done with a chisel, elevator, or most easily with a bur.

Teeth with two or more roots often need to be sectioned into single entities prior to successful removal.

A popular method of sectioning is to make a bur cut between the roots, followed by inserting

an elevator in the slot and turning it 90° to cause a break.

Roots can be removed by closed technique. The surgeon should begin a surgical removal if the

closed technique is not immediately successful.

Indications for surgical extractions:

• After initial attempts at forceps extraction have failed

• Patients with dense bone

• In older patients, due to less elastic bone

• Short clinical crowns with severe attrition (bruxers)

• Hypercementosis or widely divergent roots

• Extensive decay which has destroyed most of the crown

Root most often dislodged into maxillary sinus

# The root of which tooth is most often dislodged into the maxillary sinus during an extraction procedure?
A. Palatal root of the maxillary first premolar
B. Palatal root of the maxillary first molar
C. Palatal root of the maxillary second molar
D. Palatal root of the maxillary third molar

The correct answer is B. Palatal root of the maxillary first molar.

If an entire tooth or a large fragment of one is displaced into the sinus, it should be removed. If the tooth fragment is irretrievable through the socket, it should be

retrieved through a Caldwell-Luc approach ASAP. However, this should be performed only if the dental surgeon is well versed with the procedure, else, the patient should be referred to an oral and maxillofacial surgeon.

If a small communication is made with the maxillary sinus during extraction of a tooth, the best treatment is leave it alone and allow the blood clot to form.

Post-operative instructions to patient:

• Avoid nose blowing for 7 days

• Open mouth when sneezing

• Avoid vigorous rinsing

• Soft diet for 3 days

If a sinus communication should occur the following medications may be prescribed for one week:

1. local (nasal) decongestant

2. Antibiotics (Amoxicillin)

3. systemic decongestant

1. If the opening is of moderate size (2-6 mm), a figure of eight suture should be placed over the tooth socket.

2. If the opening is large (7 mm or larger), the opening should be closed with a flap procedure.

The integrity of the floor of the maxillary sinus is at greatest risk with surgery involving the removal of a single remaining maxillary molar. The fear here is possible ankylosis.

Ideal time to remove impacted third molars:

# The ideal time to remove impacted third molars is:
A. When the root is fully formed
B. When the root is approximately two-thirds formed
C. Makes no difference how much of the root is formed
D. When the root is approximately one-third formed

The correct answer is B. When the root is approximately two thirds formed.

• Patient would be around the age of 17-21.
• At this time, the bone is more flexible and the roots are not formed well enough to have developed curves and rarely fracture during extraction.
• When the root is fully formed, the possibility increases for abnormal root morphology and for fracture of the root tips during extraction.

Cuplike resorptive area at the crest of the alveolar bone

# A cuplike resorptive area at the crest of the alveolar bone is a radiographic finding of :
A. Gingivitis
B. Occlusal trauma
C. Early periodontitis
D. Acute necrotizing ulcerative gingivitis

The correct answer is C. Early Periodontitis 

Radiographic Changes in Periodontal Disease:

• Early periodontitis: areas of localized erosion of the alveolar bone crest (blunting of the crest in

anterior regions and a rounding of the junction between the crest and lamina dura in the posterior

regions).

• Moderate periodontitis: the destruction of alveolar bone extends beyond early changes in the

alveolar crest and may include buccal or lingual plate resorption, generalized horizontal erosion or

localized vertical defects and possible clinical evidence of tooth mobility.

•Advanced periodontitis: the bone loss is so extensive that the remaining teeth show excessive mobility and drifting and are in jeopardy of being lost. There is usually extensive horizontal bone loss

or extensive bony defects.

GUIDED TISSUE REGENERATION

# What is guided tissue regeneration?
A. A soft tissue graft used to correct mucogingival junction involvement
B. Placement of non-resorbable barriers or resorbable membranes and barriers over a bony defect
C. A free gingival graft used to increase the amount of attached gingiva
D. Placement of an autograft to treat a bony defect

The correct answer is B. Placement of non-resorbable barriers or resorbable membranes and barriers over a bony defect.

The method for the prevention of epithelial migration along the cemental wall of the pocket that has

gained wide attention is guided tissue regeneration (GTR). This method is based on the assumption that only the periodontal ligament cells have the potential for regeneration of the attachment apparatus of the tooth. GTR consists of placing barriers of different types to cover the bone and periodontal ligament, thus temporarily separating them from the gingival epithelium. Excluding the epithelium and the gingival connective tissue from the root surface during the postsurgical healing phase not only prevents epithelial migration into the wound, but also favors repopulation of the area by cells from the periodontal ligament and the bone.

The initial membranes developed were nonresorbable (polytetrafluoroethylene [PTFE]) and therefore required a second, although frequently simple, procedure to remove it. This second procedure was done after the initial stages of healing, usually 3 to 6 weeks after the first intervention. The second procedure was a significant obstacle in the uti lizat ion of this GTR technique, and therefore resorbable membranes  were developed.

Resorbable membranes marketed in the United States include OsseoQuest (Gore), a combination of

polyglycolic acid, polylactic acid, and trimethylene carbonate that resorbs at 6 to 14 months; BioGuide (OsteoHealth), a bilayer porcine-derived collagen; Atrisorb (Block Drug), a polyactic acid gel; and Biomend (Calcitech), a bovine Achilles tendon collagen that resorbs in 4 to 18 weeks. Of these, BioGuide is easier to use and generally preferred.

Currently. regenerative procedures are applicable and predictable under a certain set of circumstances:

(1) The patient exhibits exemplary plaque control both before and after regenerative therapy, 

(2) The patient does not smoke, 

(3) There is occlusal stability of the teeth at the regenerative site,

(4) Osseous defects are vertical in nature, with the more walls of bone remaining increasing the likelihood of regenerative success.

Bacteria causing ANUG

# Which of the following bacteria are commonly associated with acute necrotizing ulcerative gingivitis (ANUG)?
A. Bacteroides forsythus
B. Aggregatibacter actinomycetemcomitans
C. Actinomyces viscosus
D. Porphyromonas gingivalis
E. Treponema denticola

The correct answer is E. Treponema denticola.

Treponema Denticola is associated with acute necrotizing gingivitis/periodontitis (ANUG/ANUP).

Acute necrotizing gingivitiss igns/symptoms:
- Pain
- Interproximal necrosis of the papilla
- Bleeding gingiva
- Fetid odor
- Low-grade fever
- Pseudomembrane

Acute necrotizing gingivitis risk factors:
- Poor oral hygiene
- Smoking
- Malnutrition
- Fatigue
- Stress
- Immunocompromised patients

Aggregatibacter actinomycetemcomitans is most commonly associated with localized
aggressive periodontitis.

Porphyromonas gingivalis is most commonly associated with chronic periodontitis.

Actinomyces viscosus is associated with healthy gingivae.

Bacteriodes Forcythus is associated with chronic periodontitis.

Dentinal plugs

# Which of the following creates the phenomena of dentinal plugs?
A. Adhesive
B. Debris from the smear layer
C. Oxalic acid
D. Sclerotic dentin
E. Primer (form micro/macrotags)

Dentinal or smear plugs are composed of the debris from the smear layer.

The smear layer is documented to be about
0.5-2mm thick layer of debris with a  mainly granular substructure that entirely coverst he dentin. The surface of the smear layer appears quite irregular.

The orifices of dentinal tubules are
obstructed by debris tags known as smear
plugs or dentinal plugs. These dentinal
plugs extend into the tubules to a depth of
1-10 micrometers.

The smear layer is reported to reduce
dentinal permeability by about 86% due to
dentinal plugging.

Dentinal plugs are removed by acid etching
the tooth surface with phosphoric acid.