Recent Advances In Endodontic Surgery Presented by- Hena Rahman (JR-III)

INTRODUCTION

According to the strictest definition of the word surgery, most endodontic treatment falls into the category of a surgical procedure, since removal of tissues, such as vital pulp, necrotic debris, or dentin, is involved. However, as commonly used, the term endodontic surgery refers to the removal of tissues other than the contents of the root canal space to retain a tooth with pulpal and/or peri-apical involvement.

Endodontic surgery encompasses surgical procedures performed to remove the causative agents of radicular and peri-radicular disease and restore these tissues to functional health.

With the recent advent of magnification and illumination, coupled with ultra-sonic root end canal preparations and sealing with new retro-grade filling materials, the success of surgical endodontic treatment will provide the answer to solving myriad problems that were once considered hopeless. The expanded scope of surgical endodontics includes apical curettage, apicoectomy, root end filling, root resections, hemisections, replantation, transplantation, and guided tissue regeneration, with more advances on the horizon. This gives the clinician a wide range of choices in this conservative approach.

Microsurgery is defined as a surgical procedure on exceptionally small and complex structures with an operating microscope. The microscope enables the surgeon to assess pathological changes more precisely and to remove pathological lesions with far greater precision, thus minimizing tissue damage during the surgery. One of the most significant developments in the past decade in endodontics has been the use of the operating microscope for surgical endodontics . The medical disciplines (e.g. neurosurgery, ENT, and ophthalmology) incorporated the microscope into practice 20 to 30 yr ahead of us. It is now inconceivable that certain procedures in medicine would be performed without the aid of the microscope.The operating microscope provides important benefits for endodontic microsurgery in the following ways:

Advantages and uses of operating microscope

i. Visualization of surgical field

ii. Evaluation of surgical technique

iii. Use of fewer radiographs

iv. Patient education through video

v. Reports to referring dentists

vi. Reports to insurance companies

vii.Documentation for dental legal purposes

viii. Video libraries for teaching purposes

ix. Marketing the dental practice

x. Less occupational stress

INDICATIONS FOR ENDODONTIC SURGERY

1. Surgical DrainageA. Necessity for drainage

1. Elimination of toxins2. Alleviation of pain

2. Apical surgeryA. Irretrievable root canal fillings

1. Obviously inadequate filling2. Apparently adequate filling

B. Calcified canals

C. Procedural errors1. Instrument fragmentation.2. Nonnegotiable ledging.3. Over instrumentation and apical fracture.4. Symptomatic overfilling.

D. Presence of dowelsE. Anatomic variationsF. Apical cystG. BiopsyH. False indications.

1. Presence of an incompletely formed apex, making hermetic sealing of the apex impossible.

2. Marked overfilling.3. Persistent pain.4. Failure of previous treatment.5. Extensive destruction of peri-apical tissue and bone involving

one third or more of the root apex.6. Root apex that appears to be involved in a cystic condition.7. Presence of crater shaped erosion of the root apex,

indicating destruction of apical cementum and dentin.8. Inability to gain negative culture.9. Internal resorption.10. Extreme apical curvature.11. Fracture of root apex with pulpal death.

3. Corrective surgeryA. Root anomaliesB. Perforating carious and resorptive defectsC. Periodontal-endodontal defects

Guided tissue regeneration. Root resection, hemi section, bisection. Correction, radicular gingival groove.

4. Replacement surgeryA. Replant surgery

Intentional. Post-traumatic.

B. Implant surgery Endodontic. Endosseous.

CONTRA-INDICATIONS TO ENDODONTIC SURGERY

1. Indiscriminate surgery.2. Poor systemic health.3. Psychological impact.4. Local anatomic factors

Short root length. Poor bony support. Site of surgery.

CLASSIFICATION OF ENDODONTIC SURGERYIt can be classified as follows:

1. Surgical drainage Incision Trephination (fistulative surgery)

2. Radicular surgeryA. Apical surgery.

Curettage and biopsy (peri-radicular surgery). Apicoectomy. Retro filling.

B. Corrective surgery.1. Perforative repair.

Mechanical. Resorptive.

2. Periodontal repair. Guided tissue regeneration. Resection.

3. Replacement surgery.A. Replant surgery

Intentional Post traumatic.

B. Endosteal implants surgery. Endodontic Osseo-integrated (endosseous)

Implication of microsurgery in Endodontics

In medicine, incorporation of the concept of microsurgery began in the late

1950’s. The surgical operating microscope was used for the first time in

neurosurgery and ophthalmology in 1960. Precision is a key element in

endodontic microsurgery because of the restricted access to the surgical field.

The surgical operating microscope, which has long been a standard

instrument in medical surgery, provides the necessary illumination with a bright,

focused light and magnification upto 32x. This enhanced visibility allows the

surgeons to locate and treat anatomic variations such as partial or complete

isthmus, multiple foramina, C- shaped canals and apical root fractures. These

variations often cannot be treated by nonsurgical means.

Main advantages of microsurgical approach are small osteotomies, shallow

level, resected root surface under high magnification reveals anatomic details such

as isthumi, canal fins, lateral canals. Together with microscope, ultrasonic

instrument permit conservative coaxial root end preparations and precise retrofills.

The Differences between Traditional and Microsurgical Techniques in Endodontic Surgery

Endodontic surgery is perceived as difficult because the surgeon must often

approximate the location of anatomical structures such as large blood vessels, the

mental foramen, and the maxillary sinus. Although the chances of damage to these

structures are minimal, traditional endodontic surgery does not have a positive

image in the dental profession because of its invasive nature and questionable

outcome. If we accept the premise that the success of endodontic surgery depends

on the removal of all necrotic tissue and complete sealing of the entire root canal

system, then the reasons for surgical failure by the traditional approach become

clear. Examination of failed clinical cases and extracted teeth by surgical operating

microscopes reveal that the surgeon cannot predictably locate, clean, and fill all

the complex apical ramifications with traditional surgical techniques. These

limitations can only be overcome with the use of the microscope with

magnification and illumination and the specificity of microsurgical instruments,

especially ultrasonic instruments.

Comparing Traditional and Modern Endodontic Microsurgery

Procedure Traditional Surgery Microsurgery

Identification of the apex Sometimes difficult Precise

Osteotomy Large (= > 10 mm) Small (= < 5mm)

Root surface inspection Imprecise Precise

Bevel angle Large (45 degrees) Small (< 10 degrees)

Isthumus identification Nearly impossible Customary

Retro preparation Approximate Precise

Root end filling Imprecise Precise

Sutures 4 _ 0 silk 5_ 0, 6 _ 0 monofilament

Suture removal 7 days post-op 2–3 days post-op

Healing Success (over 1

yr)

40 – 90% 85 – 96.8%

Classification of Endodontic Microsurgical cases

Endodontic surgery can be classified as follows:-

1 Class A represents the absence of a periapical lesion, but unresolved

symptoms after nonsurgical approaches have been exhausted. The symptoms

are the only reason for the surgery.

2 Class B represents the presence of a small periapical lesion & no periodontal

pockets.

3 Class C represents the presence of a large periapical lesion progressing

coronally but without periodontal pockets.

4 Class D represents a clinical picture similar to class C with a periodontal

pocket

5 Class E classifies a periapical lesion with an endodontic and periodontal

communication but no root fracture

6 Class F represents a tooth with an apical lesion and complete denudement of

the buccal plate.

Classes A, B and C present no significant treatment problems and do not adversely

affect the successful treatment outcomes. Cases in the D, E, F categories present

serious difficulties. Although these cases are in the endodontic domain, proper and

successful treatment requires not only endodontic microsurgical techniques but

also current periodontal surgical techniques. (eg. the membrane barrier techniques)

PRESURGICAL PRECAUTIONS

Patient interview

The patient interview is an important part of the diagnostic work-up. The

interview give the surgeon the opportunity to develop thrust within the patient, to

assess the patient’s state of mind and physical conditions, most importantly to

establish a rapport with the patient. This is extremely important because most

surgeries are done under local anesthesia so the patient’s confidence in the surgeon

allays anxiety. The surgeon should also explain the microscope and microsurgical

methods. For most patients this is the first experience with a microscope,

therefore having it come within a few inches of the face can be intimidating.

Medical Evaluation

A systematic approach to determine the patient’s medical condition is

essential. Endodontic surgical procedures produce transient bacteremia, hence

antibiotics must be given prophylactically for patients with a history of rheumatic

fever, endocarditis, abnormal or damaged heart valves, organ transplants, or

placement of an implant prosthesis, such as a hip or knee replacement. It is

important that the patient be treated in consultation with the patient’s physician,

the most recent guidelines of the AHA should be observed.

Oral examination

The oral examination should be conducted in a systematic manner and in a specific

sequence. The patient’s complaint or complaints and chronologic history of the

problem should guide the line of inquiry to identify the etiology and source of the

problem. (e.g. Pain, swelling, reinforced pain such as earache and heaviness or

tightness of the jaws or muscles). An earache is usually indicative of radiating pain

from an infected ipsilateral mandibular molar tooth.

Extraoral swelling indicates that surgery should be postponed until the

swelling is reduced with oral antibiotics. If a sinus tract has developed, it should

be traced with a gutta-percha point. The tooth should be evaluated for its

periodontal integrity and for fractures. In cases designated class E or F, the

success of surgical endodontics becomes questionable.

A vertical fracture can be detected clinically or radiographically or upon

elevation of the flap.

Radiographic evaluation

Anatomic deviations, fractures, periradicular pathosis, evidence of

traumatic injuries, root resorption, periodontal disease, changes in bone patterns

and the success or failure of prior endodontic therapy can be obtained from

radiographs. Atleast two periapical radiographs taken from different angles ie one

straight on and the other 250 to 300 mesially or distally are needed to ascertain root

length, long axis, morphology and proximity to the mental foramen, inferior

alveolar nerve bundle, or the antrum which allows the clinician to visualize the

three-dimensional space.

It is very important to view the radiograph systematically.

PREMEDICATION

The drugs used in endodontic practices before and after endodontic surgery

are:-

1 Anti-inflammatory analgesics:- It is recommended that the patient (average

weight of 150lbs) take ibuprofen (400 mg) just before surgery to minimize

the postsurgical inflammatory response. To minimize bleeding problems

during surgery the dose should not be taken sooner. With this regimen

most patients will not require narcotic pain medication.

2 Tranquilizers – sublingual triazolam taken 15-30 minutes before the surgery

relieves anxiety.

3 Antibiotics – patients in poor health must be premedicated in accordance

with the most recent AHA recommendations.

4 Antibacterial rinses - Reduces microflora with a 0.12% chlorhexidine

gluconate mouth rinse (eg:- peridex, perioguard) given the night before

surgery, the morning of surgery & 1 hr before surgery. Rinsing continued

after the surgery for 1 week reduces microorganisms in the oral cavity &

promotes better healing.

LOCAL ANESTHESIA AND HEMOSTASIS

Adequate hemostasis is a prerequisite for microsurgery. For endodontic

microsurgery, effective hemostasis is essential because the bone crypt & resected

root surfaces have to be examined at high magnification.

Hemostasis in a surgical procedure can be considered in three phases

(1) presurgical

(2) surgical and

(3) post surgical.

Presurgical phase

Local Anesthesia – In surgical endodontics, local anesthesia has two prime

purposes (1) anesthesia and hemostatis. A good topical anesthetic ointment or

transoral lidocaine patch (eg: - Dentipatch) is left in place for a minimum of 2

minutes to take effect. The anesthetic solution of choice for endodontic surgery is

lidocaine 2% Hcl with 1:50,000 epinephrine. High concentration of 1:50,000

epinephrine is preferred for surgery, because it produces effective and lasting

vasoconstriction via the α-adrenergic receptors in the smooth muscle of the

arterioles. This prevents the anesthetic from being dissipate prematurily by the

microcirculation.

Epinephrine Connection – ideally for the purposes of endodontic surgery, an

adrenergic vasoconstrictor would be a pure & agonist. The predominant receptor

in the oral tissues is an - receptor, and the number of collocated - 2 receptors is

very small. Thus the drugs predominant effect in the oral mucosa, submucosa and

periodontium is that of vasoconstriction.

An aspirating syringe ensures that epinephrine is not accidentally injected

into the blood stream. Virtually the effects associated with epinephrine in dentistry

are dose – route dependent. The current recommended maximum doses of

epinephrine in local anesthetics are:

EpinephrineMg/ml

Maximum parts/thousand

Mg ml # cartridges

0.02 1:50,000 0.20 10 5.5

0.01 1:100,000 0.20 20 11

0.005 1:200,000 0.20 40 22

Clinical reasons for using 1:50,000 epinephrine

There was no correlation between the administration of epinephrine, blood

pressure and pulse rate during periapical surgery using 1:50,000 epinephrine. The

majority of patients had transitory, statistically insignificant increases in pulse rate

2 minutes after the injection. Pulse rates returned to normal within 4 minutes

Local anesthetic injection techniques

Inferior alveolar nerve block using the epinephrine – containing lidocaine

has been shown to reduce blood flow to the jaw by 90% along with buccal and

lingual infiltration to enhance the vasoconstrictive effect at the surgical site. What

ever the injection technique used for anesthesia, infiltration into the surgical site is

essential for hemostasis.

The infiltration sites for the anesthesia are in the loose connective tissue of

the alveolar mucosa near the root apices. As skeletal muscle has a predominance

of -2 receptors, the injection of epinephrine into muscle will produce vasodilation

rather than vasoconstriction and therefore must be avoided. If the anesthetic is

injected in to the muscle, not only is hemostasis inadequate, but a more rapid

uptake of the anesthetic and vasoconstrictor occurs, increasing the potential for

substantial bleeding during surgery.

Rapid injection produces localized pooling of solution in the injected

tissues, resulting in delayed and limited diffusion into adjacent tissues, minimal

surface contact with microvascular and neural channels and less than optimal

hemostasis. The initial incision should be delayed for atleast 15 minutes after the

injection until the soft tissues through out surgical site have blanched.

Maxillary Anesthesia

1 Infiltration anesthesia in the mucobuccal fold over the apex of the root and

in the adjacent mesial and distal areas is the most effective anesthesia for

maxillary teeth. For surgery on anterior teeth, a supplemental nerve block

should be injected near the incisive foramen to block the nasopalatine

nerve. For surgery in the posterior quadrant, the anesthetic is injected near

the greater palatine foramen to block the greater palatine nerve. If a patient

has a large swelling in the cuspid and premolar region, an infraorbital block

injection can be very effective to attain profound anesthesia in this area.

The choice for the supplemental anesthetic is also a 2% lidocaine

Hydrochloride (eg: xylocaine) solution with 1:50,000 epinephrine

Mandibular Anesthesia – For surgery in the mandible a mandibular and long

buccal nerve block with a supplemental infiltration injection in the mucobuccal

fold and lingual mucosa in the apical area is the most effective method. One

carpule of 2% lidocaine HCl (ie, xylocaine) solution with 1:50,000 epinephrine is

also preferred with a 27 gauge, 11-inch needle in an aspirating syringe. After the

mandibular block, another carpule is injected in to the mucobuccal fold, mesial

and distal to the tooth. After 10 minutes, another infiltration injection of one-half

carpule is made into the lingual aspect of the tooth.

Hemostatic Control during Surgery

Local hemostasis can be achieved by the pressure technique of pressing

cotton pellets or gauze into the bone crypt for a few minutes. If the bleeding

persists, topical hemostats should be considered.

Topical Hemostats

The topical Hemostatic agents are:-

Mechanical Agents

Bone wax (Ethicon, Somerville, NJ)

Chemical agents

Epinephrine – saturated cotton pellets and other vasoconstrictors.

Ferric sulfate solution

Etiologic agents

Thrombin VSP (Throbostat, Thrombogen)

Absorbable Hemostatic agents

Intrinsic action

1) Gelfoam (The Up john Co., Kalamazoo, MI)

2) Absorbable collagen

3) Microfibrillar Collagen hemostats

Extrinsic action

1) Surgicel

Mechanical

1) Calcium Sulphate

Epinephrine pellets – Racellets are cotton pellets containing racemic epinephrine

HCl. Suggested by Grossman. The amount of epinephrine in each pellet varies

according to the number on the label. For example Racellet no.3 pellets contain an

average of 0.55 mg racemic epinephrine and Racellet no.2 pellets contain 0.2 mg.

Racellet no.2 pellets do not seem to change the pulse rate of patients when pressed

into the bone cavity for 4 minutes. This is plausible because topically applied

epinephrine causes immediate local vasoconstriction, thus there is minimal

absorption into the systemic circulation.

The following procedure is most effective to achieve local hemostasis

quickly during apical surgery:-

1 A small epinephrine – saturated cotton pellet is first placed in th bony crypt

and packed solidly against the lingual wall of the bony crypt.

2 In quick succession, small sterile cotton pellets are packed in over the first

pellet, filling until the entire bone crypt.

3 Pressure is applied on these pellets and all but the last pellet is removed

after 2-4 minutes. At this time even the most persistent bleeding should

have stopped.

Ferric sulfate solution – Ferric sulfate (FS) is a hemostatic agent causing

hemostasis by agglutination of blood proteins from blood with both ferric and

sulfate ions and the acidic pH (0.21) of the solution occlude the capillary orifices.

FS affects hemostasis through a chemical reaction with blood. FS is an excellent

hemostatic agent on the buccal plate for small bleeders and is readily applied and

easily removed by the yellowish FS fluid turn into a dark brown or brown

coagulum immediately upon contact with epinephrine. The color differences are

useful for identification of the sources of any persistent bleeders. The

commercially available FS solutions are control – 50% FS, Monsel sol – 70% FS

& Stasis – 21% FS.

FS is known to be cytotoxic and to cause tissue necrosis, but systemic

absorption of FS solution is unlikely because the coagulum isolates it from the

vascular bed. FS has also been found to damage bone and to delay healing when

used in maximum amounts and when left in-situ. When the FS coagulum is

completely removed and the surgical site is thoroughly irrigated with saliva

immediately after hemostasis and before closure, there is no adverse reaction.

When there is a persistent bleeding despite of the epinephrine and cotton

pellet technique, FS solution is applied to the bone crypt. Brushing FS solution on

to the buccal surface around the bone crypt just before retrofilling ensures

hemostasis during this important procedure.

Calcium sulfate paste

It is not designed as topical hemostat. CS paste acts by mechanically blocking

blood vessels (i.e. tamponade effect). It’s a bone-inductive agent and is absorbed

by the body after 2 to 3 weeks. CS comes as a powder and a mixing solution,

which can be mixed to make a thick, pasty pellet the size of the osteotomy. After

placing the pellet into the bone, it is tamped down with a moist cotton pellet. CS

paste hardens quickly and the excess is removed, exposing the root apex for

further surgery. After the surgery, the Cs is left in the bone cavity, where it acts as

a barrier to the faster –growing soft tissue and potentially a matrix for the

osteoblasts. CS is an excellent agent for a large bone crypt that does not respond

to the other methods of hemostasis.

Other commercially available hemostats – Many other commercially available

topical hemostats are costlier effective and include bone wax, Thrombin, Gelfoam,

Collagen, Microfibrillar collagen, Hemostat (MCH), and surgical.

Calcium sulfate paste, boen wax and surgical achieve hemostasis through a

tamponade effect by mechanically blocking open vessels, whereas epinephrine

causes vasoconstriction by activating adrenergic receptors. Gelfoam made of

animal skin gelatin acts intrinsically by promoting the disintegration of platelets

causing release of thromboplastin. Collagen is known to aggregate platelets,

which then release coagulation factors. These and plasma factors help form fibrin

and subsequently a clot. Thrombin is a protein that acts rapidly in an intrinsic

fashion, combining with fibrinogen to form blood clots. MCH is prepared from

bovine corium, which promotes rapid hemostasis by attracting platelets.

Post surgical Hemostasis

To avoid post surgical bleeding, it is important that hemostasis be

maintained after the flap is sutured. An ice cold, wet, sterilized gauze placed over

the suture helps stabilize the flap and control oozing of the blood from the surgical

sites. The gauze should be placed into the mucobuccal fold for about 1hr and an

ice pack should be applied to the cheek 10 minutes on, 5 minutes off, for 1 to 2

days.

SOFT TISSUE MANAGEMENT

The soft tissue management consists of flap design, incision, elevation,

retraction, repositioning & suturing.

The two reasons for proper management of soft tissue when performing

endodontic surgery include:- to gain adequate access to the surgical site and to

ensure good post surgery healing. This can be achieved by proper flap designing

making precise incision, elevating and retracting the flap with minimum trauma to

the tissue and repositioning, suturing the flap precisely into its original position.

FLAP DESIGNS

The two major categories of flap designs are (1) Sulcular full thickness flap (or

full mucoperiosteal flap) and (2) mucogingival flap design (or limited

mucopperiosteal flap).

Design for sulcular full thickness flap

The flap design involves horizontal and vertical incisions. The horizontal incision

extends from the gingival sulcus, through the fibers of the periodontal ligament to

the crestal bone. The incision should pass through the mid-col area separating the

buccal and lingual papillae. The vertical incision should be firmly against cortical

bone between the root eminences, because the mucoperiosteum is thin over the

root eminence and tears easily. This design reflects the entire soft tissues, attached

gingival, midcol and mucosa overlying the cortical plate with the horizontal

incision being an intrasulcular incision. Thus provides the best access to all

surgical sites in the oral cavity and can be a triangular flap with one vertical

releasing incision or a rectangular flap with two vertical releasing incisions.

The rectangular design may be better for anterior teeth than the triangular

design because it provides better access to the root apex, especially when the root

is long. The rectangular design have the base of the flap as wide as the top which

follows the direction of the tissue fibers of blood vessels because less severity to

the fibers & allowing the sutured incisions to heal quickly with no scarring.

Earlier it was taught, the flap should be broader at the base to facilitate better

microvascular perfusion (ie Trapezoidal flap). In fact, the wider-based flap causes

delayed healing and unsightly scars because the incision cuts the fiber lines and

blood vessels obliquely rather than tracing them.

For posterior teeth the triangular design with one mesial vertical releasing incision

is recommended. For surgery on a mandibular first molar, the vertical releasing

incisions should be made distal or mesial of the first premolar .

In general whether it is the triangular or rectangular design, the sulcular full

thickness flap is preferred for most endodontic surgical cases.

Design for mucogingival flap:

The mucogingival flap design or limited mucoperiosteal flap design is most

suitable for crowned teeth, where there is an esthetic concern for open – crown

margins as a result of the surgery. The design calls for a scalloped incision in the

middle of the attached gingiva reflecting one half of he attached gingiva close to

the mucobuccal fold, leaving the remaining one half of the attached gingival intact

around the root and the sulcus. The angle of the incision in relation to the cortical

plate is 45 degrees, because this angle provides the widest cut surface allowing for

better adaptation once the flap is repositioned.

The mucogingival flap differs from Leubke – Ochsenbein design in that the

two vertical releasing incisions are parallel; they are wider at the base in the L – O

design. There is a significant difference in healing and potential scar formation.

The vertical incision of the mucogingival flap should be parallel. The junction

where the horizontal scalloped incision in the attached gingival meets the vertical

incision should be rounded to promote smoother and faster healing. Sharp 900

angled intersection makes healing slower and leaves a small, hard, knobby scar.

The purpose of the scalloped horizontal incision is to provide a guide for

the correct repositioning of the elevated flap for suturing which leaves a faint

unnoticeable scar in the attached gingiva.

Semilunar flap

Widely used in the past. Now rarely used because it does not allow for

adequate access to the surgical site and often leaves a noticeable scar.

FLAP ELEVATION

After giving horizontal and releasing incisions, the microperisteum is elevated and

reflected with a sharp elevator. The elevators P14S or P9 HM are placed

underneath the gingiva at the line angle. The mucoperiosteum is lifted away from

the alveolar bone by gently lifting the elevator toward the apex while it is under

the flap. The sharp wide end of the elevator is placed at a 45 degree angle to the

cortical bone surface; the mucoperiosteum peeling motion closely tracing the

cortical bone contours. The irregular surfaces of buccal cortical plates can easily

contribute to tearing or perforating the flap during the reflection. In addition to

shrinking, a traumatized flap will also swell, making it difficult to place it back to

its original position without additional trauma. A perforated or torn flap will be

difficult to suture. Moist gauze underneath the initially reflected flap helps by

gently pushing the gauze with an elevator to produce a smooth flap elevation

which have minimal bleeding.

FLAP RETRACTION

The retractor should be chosen for the specific purpose and to fit the anatomy of

the cortical plate. Retractors have narrow tips which are convex possessing

problems. Where the cortical bone protrudes the convex retractor is an unstable

anchor, because the only point of contact with the bone is the small area at the top

of the curve.

Retractors in Endodontic Microsurgery

KP retractors have wider (15mm) and thinner (0.5 mm) serrated working ends.

Some are concave & some are convex to accommodate the irregular contours of

the buccal plate. The serrated tips provide better anchorage on the bone and

prevent accidental slipping. The surfaces of the retractors are matted, so that the

light from the microscope is not reflected. KP – 1 retractor has a V shaped

working end to fit the bone eminences in the maxillary molar and mandibular

incisor regions. The KP – 2 retractor has a slight concavity in the center and is

curved gently inward to accommodate the slight bone eminences found in the

maxillary canine region. The KP – 3 retractor tip has a slight convexity that is

well suited for the mandibular premolar and molar bone anatomy. Groove

technique overcomes the danger of being close to the mental foramen during

mandibular surgery.

Repositioning of the Flap

After surgical procedures the retracted tissue is carefully repositioned with tissue

forceps. After repositioning the flap, a chilled (with ice water), damp gauze pad

is placed firmly on the flap with finger pressure to remove accumulated blood and

fruits from underneath the flap. A clean, bloodless surgical site will aid in the

accurate repositioning of the flap. Flap shrinks during lengthy surgery, hence the

flap may have to be stretched for proper adaptation and first strategic suture is

placed into the free ends of the triangular or rectangular flap. Another suture is

placed just above the free ends to reduce the tension on the free ends. The third

strategic suture is a sling suture around the tooth centre to the flap. After the flap

has reassumed its original size, the remaining sutures can be placed.

SUTURE MATERIALS AND SUTURE TECHNIQUES

Silk sutures are braided and exhibit a wicking effect that accumulates bacterial

plaques. Also causes severe inflammation to the incision site. Synthetic

monofilament sutures, such as supra mid and monovicryl, have no wicking effect,

resulting in a better, more predictable postoperative outcome. The preferred suture

size is 5 – 0 or 6 – 0. Monofilament sutures have smoothness, flexibility as

compared to 4-0 silk sutures without the risk of causing inflammation. Resorbable

gut sutures are/not recommended, except when patient can’t return. Removal of

sutures is recommended within 48 hrs. Regardless of the suture materials, the

patient must keep the surgical site as clean as possible by frequent rinsing with

warm salt water and chlorhexidine to prevent any plaque accumulation after the

surgery.

Two simple suturing techniques are there:- interrupted and sling. The

vertical releasing incision is sutured with interrupted sutures; the interproximal

and sulcular incisions are sutured with sling sutures. In the sling-suturing

technique, the buccal gingival papilla is pierced with a 3/8 inch circle or straight

5-0 suture needle that is then brought through the interproximal space of the tooth.

The suture is then led around the lingual and interproximal aspects of the tooth to

go through the adjacent buccal papilla. The path is now reversed to arrive at the

first buccal papilla, where a knot is made to secure the suture.

The value of using a microscope with this procedure is marginal, because

the site for suturing is readily seen by with 3.5 x to 4.5 x telescopes. Suturing

under the microscope provides negligible added advantage, except when a 6-0 or

smaller sutures are used. The 6-0 sutures are generally used for crowned

maxillary anterior teeth where gingival esthetics and crown margins are always a

concern.

OSTEOTOMY

Osteotomy is the removal of the facial cortical plate to expose the root end. It

must be approached with a visualized 3-D image to ensure it is made exactly over

the root apices. The first step is to expose periapical radiographic images

perpendicular to the roots from two different horizontal angles. This is done to

ascertain the length and curvature of the roots, the position of the apices in relation

to the crown, and the number of roots. In addition, the proximity of each apex to

the apices of adjacent teeth, the mental foramen, the inferior alveolar nerve, and

the antrum can be ascertained. Once the flap has been raised, the clinician should

superimpose the visualized mental image gained from the radiographs and clinical

examination onto the cortical plate.

To locate the apex:-

1) Mark the probable apex position on to the buccal plate using the radiograph

as a guide

2) Make a 1 mm deep indentation with a no.1 round, high speed bur and fill it

with a small amount of radioopaque material such as gutta-percha. A radio

graph exposed with this marker in place will show the marker in relation to

the root apex.

The microscope clearly distinguishes the root tip from the surrounding bone. The

root has a darker, yellowish color and is hard, whereas the bone is white, soft and

bleeds when scraped with probe. Root tip when cannot be distinguished,

methylene blue is used at the osteotomy site which stains the periodontal ligament.

The absence of a distinct periodontal ligament stain at mid magnification (10 x to

12X) indicates that the root tip has not yet been exposed.

Optimal Osteotomy size

Osteotomy should be as small as possible but just large enough to

manipulate ultrasonic tips freely within the bone crypt. Large size of the

osteotomy causes destruction of the buccal plate resulting in periodontic

endodontic communication. The large osteotomy causes slower and incomplete

healing period. Because the length of an ultrasonic tip is about 4 to 5 mm, leaving

just enough space to manipulate the ultrasonic tip and microinstruments within

its confines. A larger than 10 mm osteotomy was the norm with the previous

method. Under 10 x to 20 x magnification of the microscope, even a small

osteotomy looks huge. This magnified field forces the clinician to work in a small

space with small but precise movements resulting in a small osteotomy. This is

one of the true advantages of using the microscope in endodontic surgery.

Periradicular Curettage

Periradicular curettage does not eliminate the origin of the lesion it only relieves

the symptoms temporarily. The granualomatous soft tissue must be removed

completely before the apex is resected done by Columbia no.13 and no.14 curettes

or molt or Jaquette 34/35 curettes under medium magnification (10 x to 16 x)

Inspection of Resected Root Surface under the microscope

Once hemostasis is established in the bony crypt, the resected root surface

is stained with methylene blue and is examined carefully using a CX – 1

microexplorer, under 12 x to 25 x microscope magnification. The outline of the

anterior teeth demonstrate usually around outline, premolar and molar teeth

demonstrate an hourglass shape. Canal system appears elongated with more acute

bevels.

Another advantage of examining the resected root surface under the

microscope is the identification of the causes of endodontic failure. The most

frequent causes are missed canals, poor canal obturation and microfractures. The

most common failures of premicroscope endodontic surgery can be attributed to

misplaced amalgam retrofilling, apical microfractures with amalgam retrofillings

and lingual perforations of lingually positioned apices. Microleakage is the

common denomine underlying the failures in endodontics and endodontic surgery.

APICAL RESECTION

Apical resection is a root end resection or apicoectomy. Once the bone crypt is

free of granulation tissue and the root tip is clearly identified, 3 mm of the root tip

is resected perpendicular to the long axis of the root. This is done at low

magnification of 4 x to 8 x with the Lindemann bur in an Impact Air 45 handpiece

using copious water spray. Try to resect perpendicular to the long axis of the root,

especially with lingually inclined roots. The resected root surface is examined at

midmagnification (10 x to 12 x) for the presence of the periodontal ligament. This

is done to verify that the entire root tip has been removed. If the stained PDL is

visible only around the buccal aspect, the resection must be extended deeper

lingually.

Two important elements to consider with this procedure are

1) Extent of apical resection (apicoectomy)

2) Bevel Angle

Extent of Apicoectomy

The amount root tip to resect depends on the incidence of lateral canals and apical

ramifications at the root end. Using a computer system the roots of the Hess

models were resected, 1,2,3and 4 mm from the apex, counting the incidence of

lateral canals and apical ramifications at each level.

Only when 3 mm of the apex is resected are lateral canals reduced by 3 %.

Additional resection reduced the percentage insignificantly. A root resection of

3mm at a 0-degree level angle removes the majority of anatomic entities that are

potential causes of failure. Any remaining lateral canals are sealed during

retrograde filling of the canal. Therefore removing the apex beyond 3mm is of

marginal value and compromises a sound crown / root ratio.

Bevel Angle

Bevel helps the surgeon to view the apex so that it can be identified and

retroprepared. Early the bevel angle is 45 degrees. No biologic basis for this

practice existed. Bevel angle is used to 1) gain visual and operating access for

root tip /resection 2) place retrofilling materials and 3) Inspect. These reasons

were especially true for operating on lingually inclined roots eg:- mesiolingual

root of mandibular molars. Gilheany and colleagues found a positive correlation

between increasing bevel angles and increasing apical leakage. No bevels angle

thus would be best. The combination of the microscope, ultrasonic

retropreparation tips and micromirrors allows the apex to be prepared with

virtually no bevel. This is made possible by small, only 3 mm long ultrasonic tips,

which are offset by 90 degrees from the handle. Together with a small osteotomy

and bevels between 0 and 10 degrees, the minimal removal of both cortical plate

and the root apex are ensured. In this manner, surgical complications, such as the

unnecessary reduction of the crown to root ratio and creation of a periodontic

endodontic communication can be eliminated or minimized, thus preserving tooth

and bone structure promoting better healing.

The root resection must be done perpendicular to the long axis of the root.

Resections not made at 90 degrees to the long axis result in an uneven or

incomplete resection of the apex. The buccal aspect is resected but the lingual part

is partially or not resected at all, leaving leaky lateral canals. Because the apices

of many teeth (especially maxillary anterior teeth) are tilted slightly lingually,

surgeons must approach the resection with this lingual inclination in mind. The

clinician should use a 10-degree bevel and tilt the patients head to the side, away

from the microscope, for optimal viewing of the apex.

ROOT END PREPARATION

It’s the fulfillment of biologic imperative with the hermetic sealing of any

actual or potentially noxious agent within the physical confines of the root.

Ideal retropreparation

It is a class I preparation alteast 3 mm into root dentin with walls parallel to and

coincident with the anatomic outline of the pulpal space.

The root end preparations did not often follow the long axis of the root,

rather it went off to the side, occasionally perforating the lingual aspect of the root

end. Often retrofillings were too large, covering most of the resected root surface

and too shallow, resulting in a dislodged apical seal.

Major errors of retropreparation

1. Retropreparation not placed down the long axis of the pulp canal

2. Retropreparation lacks sufficient retention form

3. Retropreparation lack proper (bucco – lingual) extension to assure adequate

seals

4. Retropreparation fails to include isthmus areas

5. Retropreparation weakens delicate apical dentin by unnecessary over

enlargement

ULTRASONIC APICAL PREPARATION

One of the advancements in endodontic surgery that allowed greater efficiency

was the adaptation of piezoelectric ultrasonics for root end preparations.

Ultrasonic tips are available in various configurations (Analytic Endo, Satelect/

Amadent Co. and Spartan / obtura co.) to accommodate virtually all access

situations. These microtips are very narrow in diameter ie about one tenth the size

of a conventional microhead handpiece.

The first ultrasonic tips for endodontics and endodontic surgery were the

CT tips made of stainless steel (SS) and designed by Dr. Gary Carrin 1990. In

1999 Kis tips were introduced which have cutting efficiency by coating the tip

with zirconium nitride, more convenient angles, and relocation of irrigation port.

The location of the ultrasonic irrigation shaft, delivers maximum irrigation volume

directly into the cutting site. Kis tips are different from CT tips in terms of shaft

angle, tip angle and length.

The advantages of ultrasonic tips over microhead burs are

1 Better access, especially in difficult to reach areas as the lingual apex.

2 More thorough debridement of tissue debris.

3 Conservative preparations tracing the long axis at a precise depth of 3 mm.

4 Precise isthmus preparations with parallel canal walls for better retention of

filling materials.

Ultrasonic Root End Preparation

This procedure is accomplished under the miscroscope at low-to-mid

magnifications (14 x 16x). a number of appropriate tips are preselected,

depending upon the location of each apex. The resected root surface then is

stained with methylene blue, which must be critically examined at high

magnification (16 x to 25 x) to see the microanatomy. Thirdly, at low

magnification (4 x to 6 x), the selected ultrasonic tip is positioned at the apex. It is

important at this stage that the tip is positioned parallel with the long axis of the

root. To accomplish this, the surgeon must examine the position of entire tooth at

low magnification (4 x), including the crown and root eminence and compare this

with the position of the ultrasonic tip. Failure to make this comparison will risk an

off-angle root end preparation or perforation. Fourth, the ultrasonic tip is activated

and the apical canal is retroprepared with copious water coolant to a depth of 3

mm. For effective cutting action, a light sweeping motion using short forward and

backward and up and down strokes can be done. A typical 3 mm retropreparation

should take less than 1 minute with kis tips. Preparation is inspected with a

micromirror at high magnification of 16 x to 25 x. A thorough inspection should

include the interior canal walls for remnants of gutta-percha, especially on the

difficult –to-reach facial wall and confirmation that the parallel walls are sharply

defined and smooth.

Micromirrors

One of the key instruments in microsurgery is the micromirror. The reflective

surface is made of either highly polished stainless steel or sapphire. The mirrors

are small enough to fit into an osteotomy measuring no larger than 4 to 5 mm in

diameter. Inspection of root ends cannot be performed thoroughly without the aid

of micromirrors.

INSPECTION OF THE ROOT END PREPARATION

The root end is best prepared at low to-mid magnification (8 x to 12 x). the

preparation must be inspected at high magnification (16 x to 25 x). The completed

preparation should be inspected for clean, sharply defined walls, anatomic

structures like accessory canals and microfracture.

Depth of the root end preparation

The optimal depth of the root end preparation should be 3 mm. The

incidence of lateral canals and apical examination in the natural apex have been

studied; & over 95% of these anatomic entities are found within the apical 3 mm.

Although a retropreparation deeper than 3 mm does not provide any greater

benefits, a retropreparation shorter than 3 mm may jeopardize the long-term

success of the apical seal.

COMPACTION OF GUTTA-PERCHA IN THE RETROPREPARED

CAVIY

The remnants of gutta-percha have to be compacted well to a 3 mm depth

with microcondensers. Many different type of micro condensers with different

handles are there, but their working tips are basically the same, with a 0.2 mm

diameter and a length. The retroprepared canals must be void of any gutta-percha

or debris for the final filling.

Retrogate filling materials are:-

- Amalgam

- Guttapercha

- Gold foil

- Titanium screws

- Glass ionomers

- Ketac silver

- Zinc oxide – eugenol

- Cavit

- Composite resins

- Polycarboxylate cement

- Poly HEMA

- Bone cements

- IRM

- Super EBA

- Mineral Trioxide Aggregate (MTA)

ISTHUMUS

In general sense it is a narrow strip of land connecting two larger lands . Isthmus is

a narrow connection between two root canals which usually contains pulp tissue.

The isthmus has been called a “corridor” by Green, a “lateral connection” by

Pineda and an “anastomosis” by Vertucci. In many teeth with a fused root there is

a weblike connection between two canals called an isthmus, which can be either

complete or incomplete. At 3 mm from the apex, isthmuses are often found to

merge two canals in one root. Thus isthmus is a part of a canal system and not a

separate entity; accordingly, it must be cleaned, shaped and retrosealed.

Isthmus frequency

The isthmus is most frequently observed between two root canals within one root.

Thus, the majority of posterior teeth contain an isthmus. At the 3-mm level from

the original apex, 90% of the mesiobuccal roots of maxillary first molars have an

isthmus, 30% of the maxillary and mandibular premolars, and over 80% of the

mesial roots of the mandibular first molars have one. This high incidence of

isthmuses in premolars and molars is an important consideration when performing

apical surgery. This is one of the reasons why apicoectomy alone, without root-

end preparation and/or root-end filling, especially in molar teeth, usually fails.

Importance of Finding and Treating the Isthmus

When an isthumus was present, these cases would eventually fail.

Isthumuses should be identified, prepared and properly sealed' The high incidence

of isthumi found during microsurgery was surprising and prompted an anatomic

investigation. The untreated isthumi are one of the main causes of treatment failure

of apical surgery, especially in the posterior teeth.

POSTOPERATIVE SEQUELAE

Surgical sequelae include pain, swelling, ecchymosis laceration, premature

separation of sutures, infection maxillary sinus perforation and transient

paresthesia. To minimize postsurgical sequelae, oral and written postoperative

instructions must be given to the patient and the person accompanying the patient.

Because of anxiety and nervousness, patients sometimes misunderstand or simply

do not remember the verbal instructions for this reason written instructions allay

confusion or further anxiety.

Pain

Pain is usually not a serious problem. Long-acting anesthetic agents such as

bupivacaine (ie mercaine) or etidocainel (ie, Duranest) can be injected

postoperatively in to the surgical site to control pain for a period of upto 8 hours.

Ibuprofen or acetaminophen regimen always ensures that any pain will be minimal

and transient. Rarely are narcotic analgesics required.

Hemorrhage

Postoperative haemorrhage is rare. To prevent it from occurring two 2 x 2 sterile

gauze pads are folded in half and moistened with chilled, sterile water. This pack

is placed over the sutured flap in the buccal fold and pressed by the surgeon with

moderate pressure for several minutes. The patient is provided an ice pack to

press lightly against the cheek or jaw for at least 30 minutes to constrict the cut

microvasculature, minimizes swelling and promotes initial coagulation.

Swelling

Swelling is a common surgical sequelae & is a major concern for the

patient. Patients must be informed that the surgical site and face may swell

regardless of the home care. Also, patients must be assured that the degree of

swelling is not an indication of the success or failure of the surgery or the severity

of the case. Intermittent application of ice packs, 10 minutes on an 5 minutes off,

for the first 2 days almost minimizes swelling.

Ecchymosis

Ecchymosis is the discoloration of facial and oral soft tissues because of the

extravasation and subsequent breakdown of blood in the intestinal subcutaneous

tissues. This is basically an esthetic problem. It is more prevalent in elderly

patients with capillary fragility and patients with fair skin. Frequently, ecchymosis

occurs below the surgical site because of gravity. The ecchymosis for the

maxillary premolar surgical site is found in the neck area. The patient should be

assured that the ecchymosis has no bearing on the success or severity of the case.

Paresthesia

When Paresthesia occurs, it is when the mental nerve presents near the second

premolar and first molar. Transient paresthesia may occur even if the surgical site

is far from the nerve. Inflammatory swelling of the surgical site may cause

temporary impingement on the mandibular nerve causing transient paresthesia. If

the nerve has not been severed, normal sensation generally returns within a few

weeks. Rarely, it may take a few months to regain normal sensation. The patient

should be assured of the probable return of sensation in the affected side.

Paresthesia some times can be permanent.

Maxillary sinus perforation

Perforation of the schneiderian membrane covering the sinuses may occur. If

perforation of the sinus occurs, utmost care should be taken to prevent any

material from entering the sinus.

The patient should be instructed to elevate the head during the night. Prophylactic

antibiotic therapy with augmentin 500 mg every 6 hours along with Sudafed for 1

week should be prescribed. The patient should return for a postsurgical checkup

in 1 week.