Microsurgery Flashcards
Q254 : Describe the stages of wound healing?
In a three-part study, Harrison & Jurosky (part 1), (Part 2) 1991, and (Part 3) 1992 they described the stages of wound healing into 4 stages:
1. Clotting and Inflammation: The fibrin clot forms extravascular day 1 - PMN move in and predominate for 12 hours then macrophages take over.
- Epithelial healing: Epithelial cell migrate over a fibrin substrate to form an epithelial seal. Initial migration from the unflapped side. Increase mitosis leads to an epithelial barrier
- Connective tissue healing: Macrophages stimulate migration and activity of fibroblasts. The fibroblast synthesizes ground substance and collagen. This transitions from granulomatous tissue to a granulation tissue, which is highly vascular with fibroblast, signals the successful progress of connective tissue healing.
- Maturation and remodeling: fibroblasts decrease and there is a reduction in the vascular channels. This begins the phase of maturation, which involves re-organization of collagen. The fibers increase in size, strength and insolubility through cross-linking.
Q255 : During endodontic surgery, vertical releasing incision should…
be perpendicular to the sulcular incision
Kindlová (Archives of oral Biology 1965) examined the blood vessels supplying the periodontium and showed that the blood vessels run vertically in the oral mucosa. Thus, vertical releasing incisions should be as perpendicular as possible to any horizontal incision created (sulcular, sub-marginal or papilla based). The incision should also be practical. If needed to be modified, it can be slightly obtuse. An acute angle should be avoided as sharp corners may affect proper adaptation of the flap and can result in poor healing.
Q256 : Which of the following roots has the closest approximation to the mandibular canal?
Mesial root of 2nd molar
In a CBCT study by Kovisto et al (JOE-2011), mandibular 2nd molar
had the closest approximation to the mandibular canal.
Also, females had closer roots to the canal compared to males.
Q257 : What is the incidence of odontogenic tumors among oral lesions?
Daley et al. (000-1994) investigated the relative incidence of odontogenic tumors and oral and jaw cysts in a Canadian population. Among 40,000 consecutive oral biopsies, the incidence of odontogenic tumors was 1.1%
- 51% odontomas (radiopaque)
- 13% Ameloblastoma (multi-locular)
- 9% Peripheral Odontogenic fibroma (soft tissue swelling)
Q258 : What does the term “Decompression” mean? and what are its clinical indications?
Decompression is a minor surgical procedure whereby a small opening is made into a cystic cavity and maintained to relieve pressure and to ensure constant drainage. This opening is kept patent by using an indwelling catheter (rubber dam, metal tube, polyethylene or polyvinyl tubing) until the cystic perpetuating conditions have been altered sufficiently to anticipate uneventful healing. The altered conditions include the cessation of drainage, the elimination of metabolic debris from apical area, a reduction in size of the cystic space, and the alleviation of patient discomfort. Only then is the opening allowed to close (Neaverth & Burg, JOE - 1982).
This technique is indicated when enucleation of the entire lesion may result in:
1- Devitalization of adjacent teeth
2- Damage to anatomic structures (IAN, Sinus)
3- Loss of bony support
4- Paresthesia
Q259 : What is the average amount of blood typically lost during root end surgery?
10ml
Selim et al (Dent Traumatol- 1987) investigated the volume of blood lost during endodontic surgery. Blood loss averaged 9.5 ml for all patients, with a range of 1.2 to 48.4 ml. Operating time was the major variable influencing factor.
It has been shown by Buckley et al (J Periodontol 1984) that the amount of blood loss during surgery can be reduced in half when using lidocaine anesthesia with 1/50,000 epinephrine instead of 1/100,000.
Q260 : Can hemostatic agents used during endo-surgery result in cardiovascular changes?
No
Viker et al (JOE - 2002) showed that the use of ferric sulfate & epinephrine pellets to achieve hemostasis during endo surgery resulted in no significant changes in blood pressure or pulse.
Q261 : How to manage a sinus perforation during endodontic surgery?
During the surgery
- cover the perforation with a membrane or gauze to avoid dropping any materials into the sinus. If bone graft is needed, a membrane should be placed against the perforated sinus prior to placing the bone graft.
Water-tight suture to avoid any oro-antral communication.
After the surgery
- Prescribe decongestants (5% neosynephrine)
- Antibiotics (broad spectrum or antibiotics that address gram negative bacteria, such as metronidazole)
- Ask the patient to avoid nose blowing and sneezing
- Tell the patient that it is expected to have some blood coming out of their nose (particularly while sleeping, they may find blood on their pillow)
Q262 : What is the incidence of metastatic tumors in the oral cavity?
Kumar & Manjunatha (J Oral Maxillofac Pathol - 2013) investigated metastatic tumors to the jaws and oral cavity. They found that 1-3% of all malignant oral neoplasms were metastatic tumors.
Mandible was the most common location for metastases and molar area were the most frequently involved site. This may stem from the poor blood supply to these areas.
Q263 : How much of the root end should be resected during an apicoectomy?
3mm
Kim et al (Color Atlas of Microsurgery, 2001) reported that root canal anatomy is similar between sections at 3 mm from the apex and those at 4, thus there is no need to cut more than 3mm. The apical 3 mm of the root canal contains around 98% of the ramifications and 93% of the lateral canals
It should be noted that each case should be evaluated separately as in some cases, cutting 3mm of the apical segment may compromise the crown/root ratio or may compromise the thickness of the root end filling material (example cases with very long posts).
Q264 : Explain why Calcium silicate materials, such as MTA, can be more superior than other previously used retro-filling material (IRM Super EBA, amalgam etc) in periapical surgery?
-MTA can set in presence of moisture and is more resistant to leakage than the other aforementioned material (Torabinejad et al, JOE - 1994).
- It has been shown by Baek et al. (JOE-2005) that a newly formed cementum coverage can be formed over the MTA (Biological barrier) but not over amalgam or super EBA.
Q265 : What is the purpose of placing a retro filling material during root-end surgery?
To create an adequate apical seal. Following apicoectomy, gutta percha becomes exposed to blood from the surgical site, which would result in apical leakage.
Kruse et al. (JOE - 2016) showed that the success rate of root end surgery was 30% higher after 6 years when MTA was placed as a retro-filling material compared to just cutting the apical root segment and smoothening the gutta percha. Similar results were also shown by Christiansen et al. (IEJ -2009)
Q266 : Is there any superiority of endodontic microsurgery over traditional endo surgery?
Yes
Setzer et al. (JOE - 2010) conducted a meta-analysis of the literature to Investigate the outcome of root-end surgery of traditional root-end surgery (TRS) Vs endodontic microsurgery (EMS). They showed that the probability of success for EMS was significantly greater (94%) than the probability of success for TRS (59%). They also showed in 2012 **(Setzer et al, JOE - 2012) **that the probability for success of root end surgery using microscopes was significantly greater than the probability for success for root end surgery with loops or no magnification.
Tsesis et al. (JOE - 2013) showed that the type of retro-filling material and magnification device may affect the outcome of surgical endodontic treatment.
In a 5 yrs. controlled clinical trial by Tortorici et al. (J CranioFaci Surg - 2014) Modern apicoectomy resulted in a significantly higher probability of success compared to traditional techniques.
