A D VA NC E S I N S U R G I C A L ENDODONTICS

ARNALDO CASTELLUCCI, MD, DDS

Pag. - 2

Advances inSurgical Endodontics

Arnaldo Castellucci, MD, DDS

IntroductionBy Surgical Endodontics one refers to that branch of Dentistry that is concer-ned with the diagnosis and treatment of lesions of endodontic origin that do not respond to conventional endodontic therapy or that cannot be treated by conventional Endodontic therapy.The scope of Surgical Endodontics is to achieve the three dimensional cleaning, shaping and obturation of the apical portion of the root canal system which is not treatable via an access cavity, but only accessable via a surgical flap (Fig. 1). For this reason it is preferable to use the term Surgical Endodontics rather than Endodontic Surgery, in as much as the procedure should be plan-ned and carried out as an endodonticprocedure via surgical access and not a surgical access and not a surgicalsurgical procedure done for endodonticreasons.Once a diagnosis of Endodontic failure has been made, it is necessary to under-stand what the cause of the failure was so that successively the possibility of correcting the failure by orthograde retreatment can be evaluated.Only in the case where this possibility does not exist or better still after fai-

lure of the non-surgical therapy carried out to resolve the problem, only then is one authorized to intervene surgically. Apical Surgery in other words is not a substitute for incomplete debridement and poor endodontics (Fig. 2).In agreement with what Nygaard-Ostby and Schilder 8 confirmed, Surgical Endodontics must be reserved for those cases in which the preparation and obtu-ration of the root canal appear impossi-ble right from the beginning or when the non-surgical retreatment attempts have failed. Nevertheless, even in such cases, the authors recommend filling as much of the root canal by conventional method as possible.Currently the technique and instrumen-ts for clinical retreatment of endodon-tic failures are so refined that the cases that for certain have to be treated sur-gically because they cannot be retrea-ted by orthograde means are becoming fewer. Often a high level of Surgical Endodontics experience masks the ope-rators inability to carry out a correct cleaning, shaping and three dimentional obturation of the root canal system by non-surgical means.

1a

Fig. 1A typical example of Surgical

Endodontics. a. Pre-operative radio-graph. b. There are two sinus tracts

present. c. Post operative radiograph: the main and the lateral canals were

retreated surgically. d. Two year recall.

1b 1c 1d

Pag. - 3

Ultimately even after the indication for surgery has been established, in agree-ment with Weine and Gerstein,17 it is recommended to remove as much as possible of the inadequate preceeding canal obturation material and replace it with well compacted guttaperca: in this way lateral canals, forgotten additional canals can be filled, often removing the need for surgery (Fig 3).Nevertheless, in those cases which still have the indication for surgery it is cur-rently possible to have a notably increa-

sed percentage of success with the treat-ment of surgical cases compared with what could be attained up untill a few years ago, and this is thanks to recent technological progress that has happe-ned in the field of Surgical Endodontics.In the last 10-15 years two important developments have been introduced in surgical endodontics: the ultrasonic root end preparation and the surgical opera-ting microscope.

2a

Fig. 2A typical example of Endodontic Surgery: the procedure was carried out after failure of a poorly executed orthograde therapy. a. Preoperative radiograph. b. Postoperative radio-graph after orthograde retreatment. c. After a few months the patient pre-sented with a fistula: now there is an indication for surgical retreatment. d. Postoperative radiographs : Super EBA was used as a retrofilling mate-rial. e. Two year recall.2b

2c 2d

2e

Fig. 3a Due to presence of material beyond the apex and the closeness of the preceeding root canal obturation to the bifurcation, there could be an indi-cation for surgical retreatment.3b

Pag. - 4

The ultrasonic preparationFor many years the root end has been surgically prepared drilling a class 1 pre-paration into the dentin, using a strai-ght slow-speed handpiece or a so called “miniature” contra-angle handpiece (Fig. 4) with small round or inverted-cone carbide burs. This approach had many disadvantages, mainly the impossibility to create a preparation in the longitudi-nal axis of the root canal and to clean the buccal surface of the root end. Trying to give enough retention to the cavity, the risk of a palatal or lingual perforation was always present and the procedure was more and more difficult as the root canal was more and more difficult to reach from the operator. The smallest burs were always too big compared with the diameter of the root canals and the

big cavities were therefore more difficult to seal. For the same reason, retroprepa-rations often failed to include isthmus areas.The introduction of the ultrasonic root end preparation made possible to obtain what is defined as the ideal retropre-paration: a class 1 preparation at least 3 mm into the root dentin with walls parallel to an coincident with the ana-tomic outline of the pulpal space.1,3 In order to do this, special ultrasonic tips were developed to enable the clinician to reach every root in all clinical situations.The use of the specifically designed retrotips allows the operator to clean the root canal from an apical approach, lea-ving clean dentinal walls not only on the lingual or palatal side, but also on the buccal aspect, which was impossible to clean with the previous techniques. The cavity now can be made 3 mm deep, without the necessity of making under-cuts, since there is no need of further retention. The retrotips are of the same size or even smaller compared to the original size of the root canal, so that the retroprepara-tion can be easily and predictably sealed in the maximum respect of the original anatomy. The isthmus area can now be included into the preparation, without damaging or weakening the root, while being extremely conservative in the mesio-distal dimension.4

Fig. 4The smallest contra-angle handpiece

is too big compared to the ultrasonic retrotip

Fig. 3bOrthograde retreatment was carried

out which brought to light the pre-sence of two missed canals, the disto-

buccal and the mesio-medial canal.

Fig. 3cThe five year recall shows the comple-

te healing of the lesion and complete disappearance of the extruded apical material, confirmation that a “foreign body reaction” is an excuse invented

by someone that does not want to and does not know how to prepare

canals in their entire length.

AUTHOR PROFILE. Dr. Castellucci graduated in Medicine at the University of Florence in 1973 and he specialized in Dentistry at the same University in 1977. From 1978 to 1980 he attended Continuing Education Courses on Endodontics at Boston University School of Graduate Dentistry. He limits his practice to Endodontics. Dr. Castellucci is Past President of the Italian Endodontic Society (S.I.E.), Past President of the International Federation of Endodontic Associations, an active member of the European Society of Endodontology, an active member of the American Association of Endodontists, and a Visiting Professor of

3c3a

Pag. - 5

The surgical operating microscopeThe introduction of the surgical opera-ting microscope (Fig. 5) represents the other important development in surgical endodontics.2,10 For many years periapi-cal surgery has been performed without any magnification, using the dental light as the only light source to illumi-nate the surgical field. No surprise the-refore if until recentely the success rate after surgery was much lower compared to nonsurgical endodontics.4 To increase visibility, surgical telescopes or loops and surgical headlamps became availa-ble. Loops are available in a variety of configurations and magnifications, star-ting from 2x up to 6x, with Galileian optics or prismatic optics. When a fibe-roptic headlamp is added to the loops, a coaxial light is projected into the sur-gical field, so that both magnification and illumination are enhanced. On the other hand, how much magnification is enough? Clinicians who have benefited

from the use of loops and headlamps soon understand the limitations of this system. Magnification of 6x sooner or later is not enough anymore and the hea-dlamp is not capable to send the light deep into the canal in surgical and non-surgical endodontics. The right answer to the previous question is: “enough to see and solve the problem”. The surgi-cal operating microscope has a range of magnifications from 2.5x to 25x and the illumination is coaxial with the line of sight. The coaxial illumination has two advantages:a) the clinician can look into the surgical field without any shadows (which means that it is possible to examine the cleanli-ness of the retropreparation during sur-gical endodontics);b) since the coaxial illumination is made possible because the operating micro-scope uses Galileian optics, and since Galileian optics focus at infinity and send parallel beams of light to each eye,

5Fig. 5The surgical operating microscope.

Endodontics at the University of Florence Dental School. He is the Editor of “The Italian Journal of Endodontics ” and of “The Endodontic Informer”, Founder and President of the “Warm Gutta-Percha Study Club” and of the Micro-Endodontic Training Center. An inter-national lecturer, he is the author of the text “Endodonzia”, which will soon be published in English. He lives and practices in Florence, and can be reached at 39 055 571 114 or at castellucci@dada.it

Pag. - 6

Advances in Surgical Endodontics

the operator’s eyes are also focusing at infinity and every procedure can be per-formed without any eye fatigue.As far as the magnification is concerned, there is no need to go beyond 25-30x. Lower and medium magnifications are used for operating; higher magnifica-tions are used only for observing fine details. Working at high magnifications means to have a very limited depth of field and limited illumination, and the-refore is not practical.9

The use of the surgical operating micro-scope has several advantages in surgical endodontics: a) better visualization of the surgical field; b) better evaluation of the surgical technique; c) better accuracy during the entire procedure; d) better predictability of long term resultsFor these reasons, the author is firm-ly convinced that surgical endodontics should not be performed without the use of the microscope, from the incision to the removal of sutures.Under the microscope, the incision made with the microsurgical scalpel is more accurate, with less trauma to the soft tissue, a more passive flap elevation and later reapproximation is semplified. At minimum magnification, the entire surgical field can be observed (Fig. 6), looking for the mental nerve (Fig. 7), for instance. The size of the osteotomy is

usually small (usually less than 5 mm), big enough to accomodate the ultrasonic tips, which have a tip length of 3 mm. Working at 10x to 20x magnifications, the small osteotomy allows a perfect control of the entire surgical procedure.

Microsurgical techniqueAnesthesiaIn surgical endodontics the goals in anesthesia are to provide profound ane-sthesia not only for the procedure, but also for a prolonged period of time fol-lowing the surgery and also to provide a good hemostasis.1 For this purpose, the anesthesia of choise is 2% lidocaine with 1:50.000 epinephrine. Other ane-sthetic solutions with less epinephrine are contraindicated, because the ecces-sive bleeding of the surgical site will compromise surgical visibility. The slow administration of anesthetic solution with 1:50.000 epinephrine has no con-traindication even in medically compro-mised patients. The use of the microsco-pe during the administration of the ane-sthetic solution is helpful to avoid the injection near bigger capillary vessels and can guarantee almost no bleeding once the needle is removed.

IncisionUsing microsurgical scalpel blades

6

Fig. 6At minimum magnification, the entire

surgical field can be observed.

Fig. 7During a surgical procedure in a lower quadrant, it is necessary to locate the mental nerve to avoid any damage to

this important anatomic stucture. 7

Pag. - 7

8

Fig. 8The microsurgical scalpel blade CK2 by Analytic Endodontics compared with the Bard-Parker # 15.

(Fig. 8) under the microscope even at minimum magnification, the surgeon can make a very precise incision with minimum damage to the soft tissue. If enough attached gengiva is present, the mucogengival incision is preferable, in order to preserve the existing epithelial attachment. If there is limited attached gengiva or if there are short roots or large periapical lesions or when the cer-vical aspect of the root must be exami-ned because for istance a vertical root fracture is suspected, the flap of choice is the triangular or rectangular flap with sulcular incision. In both flaps, the ele-vation must be undermined, to reduce the trauma to the soft tissue: the ele-vation begins at the vertical releasing incision and continues to the coronal margins in an apical-coronal direction. The mucogengival incision is scalloped, to facilitate reapproximation.

OsteotomyWith a round surgical bur mounted on a straight slow speed handpiece and under copious irrigation with saline solution the surgeon starts the removal of bone to isolate the root apex. If the cortical plate has been perforated by the lesion, the location of the root apex is very easy and the removal of bone is minimum. If the cortical plate is still intact, the gentle removal continues until a diffe-rence in color is appreciated: the yel-lowish dentin can be easily recognized against the white bone. The osteotomy must be large enough to provide good visibility and to allow the use of all necessary instruments: curettes, retroti-ps, micropluggers. Once the root apex is identified, the lesion is removed in toto to provide a better control of the bleeding and later a faster healing. The complete removal of the lesion is con-traindicated if the aggressive curette-

ment could endanger anatomic structu-res, such as mental or mandibular nerve, maxillary sinus or floor of the nose. It is well known that healing of lesions of endodontic origin proceeds only after the removal of contaminants from the root canal system and not just removing the inflammed tissue surgically.1

Apical resectionThe apical resection is made using a Lindemann bone-cutting bur on a high speed handpiece specifically designed for oral surgery: it has no air out-put to eliminate the danger of air embolism and the bur is mounted at a 45° angle to enhance visibility under the microscope, especially in posterior teeth. The apical resection is made almost perpendicular to the long axis of the root and must be complete both in bucco-lingual and in mesio-distal directions.1,5

The microscope is very helpful in loca-ting the root canal, to evaluate the presence of multiple portals of exit, to locate and then eliminate the extruded filling material and the old and failing amalgam retrograde, the apical root fracture, and the accessory canal on the root surface. The best way to inspect the surface of the beleved root is painting a small amount of methylene blue dye: it will

Pag. - 8

Advances in Surgical Endodontics

be a lot easier to verify that the root has been completely sectioned, that an isth-mus is present, and that a vertical root fracture is present (Figs. 9-16).

Bleeding controlIt is imperative that the retrofilling

procedure is made in a dry field. For this purpose, the bleeding inside the bony cript must be totally eliminated and totally under control. The dental assistant uses a small suction tip and follows the entire procedure using the assistant scope. She will help to main-

11 12

13 14

Fig. 11After the removal of about 1 mm of root structure and a second applica-tion of methylene blue the fracture

disappeared: the prognosis is now very good.

Fig. 12The retropreparation has been com-

pleted with ultrasonic tips.

Fig. 13Fitting the microplugger.

Fig. 14The retrofilling material (Super EBA)

is now carried to the apicalpreparation.

9

Fig. 9The methylene blue dye is used to

detect an apical root fracture.

Fig. 10The apical vertical root fracture is

now evident. 10

Pag. - 9

tain a dry field and a good visibility for the surgeon. If the suction is not enough to keep the blood away from the beveled root surface, a few drops of anesthetic solution with 1:50.000 epi-nephrine are placed on a sterile gauze and then pushed against the walls of the bony crypt for a few minutes. Another more efficient method to completely eliminate the bleeding from inside the crypt is the use of ferric sulfate, which causes instantly a very good hemostasis, having an extremely low pH (0.21) and causing rapid intravascular coagulation. The use of ferric sulfate has no contrain-dications, but it must not be used in contact with important anatomic struc-tures, like mandibular or mental nerve, maxillary sinus or floor of the nose. Its use is also to be avoided on the corti-cal bone and on soft tissues. When the retrofilling procedure is completed and before suturing, it is also imperative to completely remove it in order to avoid a delay in the healing process.6,7

Apical retropreparationA large variety of retrotips are today available to make what has been defined as the ideal retropreparation. Several ultrasonic units specifically designed for root end preparation are also commer-cially available. The first retrotips intro-duced into the market were designed by Gary Carr3 and were available in diffe-rent sizes, the standard CT Tips (Fig. 17) and the smaller SLIM JIM tips (Fig. 18). A special tip to work in roots with a very pronounced lingual inclination is

Fig. 16A. Preoperative film. The first right upper premolar has a broken instru-ment in the palatal root and gut-tapercha extruded from the buccal root. During the surgical procedure appeared evident that the guttaper-cha was extruded through an apical fracture caused during the obturation made with lateral condensation. B. Postoperative film. C. Two year recall.

15

16a 16b 16c

Fig. 15The retrograde has been finished.

Pag. - 10

Advances in Surgical Endodontics

17

Fig. 17The standard ultrasonic retrotips desi-gned by Gary Carr. From left to right:

CT 1, CT 5, Back Action tip.

Fig. 18The small SLIM JIM tips, # 1 and # 5. 18

19

the Back Action Tip, designed by Gary Carr (Fig. 19).Recently, Syngcuk Kim designed new tips made in stainless steel coated with zirconium nitride (Fig. 20a).They are called KiS Microsurgical Ultra-sonic Instruments and they have several advantage:a) they are more aggressive and cut den-tin faster, without need for repeated ultrasonicsb) the irrigation port has been placed near the working tip, with increased efficiency and more abundant irrigation during the retropreparation (Fig. 20b)c) they are slightly longer than other retrotips, for better access to areas diffi-cult to reach.Retrotips coated with diamond are also available, like the ones designed by Elio

Berutti (Fig. 21). Very useful are also the retrotips designed by Bertrand Khayat BK3, with three bends specifically made to reach areas of difficult approach (Fig. 22).The retrotips should be placed perpendi-cular to the long axis and then activated. The tips should penetrate the old filling material without resistance. They should be disactived before their removal from the root canal. This is done to avoid a scratch or any kind of damage to the surface of the root bevel. The removal of the previous failing amalgam retrofill is also facilitated by the use of the retro-tips which many times can remove the old filling in one single piece, without risk of tatoo. If the root to be treated has two or more canals, the surgeon must be very careful and look for the isthmus, which contains pulp tissue and debris as any other endodontic space and the-refore must be cleaned and incorpora-ted into the retropreparation (Fig. 23). Failure to prepare and seal the isthmus is an invitation for failure. The isthmus sometimes can be so narrow that it is difficult to see even under the micro-scope. Therefore, as a general rule, in all roots with multiple canals the isthmus must always be prepared,1 even though we cannot see it with the microscope!Once the ultrasonic preparation is com-

Fig. 19The Back Action tip is indicated in

roots with a very pronounced lingual inclination.

Pag. - 11

pleted, it is examined for completeness. If debry are still present, the surgeon can use again the retrotip, irrigate and reexamine the retropreparation. The cavity should be 3 mm deep and the walls completely free of the old gutta-percha or sealer (Fig. 24). The operating

microscope is crucial to examine the accuracy of the retropreparation and this is done with the use of the micromirror (Fig. 25) after the cavity has been irriga-ted with saline solution and dried with a light system of air using the Stropko surgical irrigator12 (Fig. 26).

20a

21

20b

22

Fig. 20The KiS Microsurgical Ultrasonic Tips designed by Syngcuk Kim. Note the irrigation port very close to the working tip.

Fig. 21The retrotips designed by Elio Berutti are diamond coated (EMS).

Fig. 22The retrotips BK3 designed by Bertrand Khayat (Analytic Endodontics) have three bends specifi-cally made to work easily in posterior teeth.

23 24

Fig. 23Stereo-microscopic view of the retro-preparation made in a third molar by a dental student: the isthmus has been incorporated into the retroprepara-tion, with the maximum respect of the root canal anatomy.

Fig. 24Stereo-microscopic view of a clean retropreparation.Stropko surgical irrigator.

Pag. - 12

Root end filling materialsHistorically, amalgam has been the retrofilling material of choice for many years, but today it is not used anymo-re since it has several disadvantages, like corrosion, expansion, and leaka-ge. The most widely accepted retro-filling materials today are zinc oxide-eugenol cements, like IRM and Super EBA.8 They are easy to manipulate, have adequate working time, dimensional-ly stable, biocompatible, unaffected by moisture, bacteriostatic, radiopaque, don’t discolor the tooth or the surroun-ding tissues and are easy to remove. The Super EBA cement is mixed to a putty consistency, shaped into a narrow cone, attached to the end of a spoon excavator or a little spatula and carried to the apical preparation10 (Fig. 27).

25 26

27

The cone of material reaches the base of the preparation and the sides of the cone contact the walls. Between each aliquot of material, a pre-fitted plugger is used to condense the Super EBA. The material is condensed in excess on the beleved surface of the root using a ball burnisher (Fig. 28). When the cement has set, a finishing bur is used to finish the retrofilling (Fig. 29). The integrity of Super EBA is then examined at high magnification after the surface has been dried with the Stropko irrigator (Fig. 30). A post-operative radiograph is now exposed and then the surgeon is ready to suture the flap.As an alternative to ZOE cements, a new material has been recently introdu-ced in endodontic surgery as a retrofil-ling material11,13,14,15 (Fig. 31). Mineral Trioxide Aggregate is a powder consi-sting of fine hydrophilic particles of tri-calcium silicate, tricalcium aluminate, tricalcium oxide and silicate oxide. It also contains small amounts of other mineral oxides, which modify its chemical and physical properties and make the mate-rial radiopaque. Hydration of the powder results in a colloidal gel that solidifies to a hard structure in approximately three hours. MTA has several advantages:a) easy to mix and place into the cavity with a small carrier

Advances in Surgical Endodontics

Fig. 27The narrow cone of Super EBA is

attached to the end of a little spatula and carried to the apical preparation.

Fig. 25Note the size of the most commonly

used micromirror, compared with a standard dental mirror. The micromir-ror on the right is 3 mm in diameter.

Fig. 26The retropreparation is dried with the

Stropko surgical irrigator.

Pag. - 13

Vol. 6, Nr. 1 2003

L’Informatore Endodontico

28 29

b) since it sets in the presence of moistu-re, it is not moisture sensitivec) seals better than amalgam or Super EBAd) has a better adaptation to the sor-rounding dentine) has excellent biocompatibilityf) activates cementogenesis (Figs. 32-33).

MTA can be difficult to manipulate in narrow retropreparation and the long setting time could be considered a disa-vantage.

SutureSuturing under the operating microsco-pe has the advantage of being more accu-rate in repositioning the flap, allowing a

Fig. 28The excess material is condensed with a ball burnisher.

Fig. 29A finishing bur is used to finish the retrofilling.

30 31

32a 33a32b

Fig. 30The integrity of the retrofilling is exa-mined at maximum magnification.

Fig. 31The white ProRoot MTA (Dentsply Tulsa Dental, OK)

Fig. 32A. Preoperative film. Two retrofillings made in amalgam are failing. B. The six month recall shows the perfect hea-ling after the surgical retreatment and the use of MTA as retrofilling material (Courtesy of Dr. Luigi Scagnoli).

Pag. - 14

perfect healing by primary intention, without any scar tissue. The author disa-grees with people who recommend the use of the microscope for osteotomy, curettage, apicectomy, apical prepara-tion, retrofilling and documentation but not for suturing as well as for the inci-sion. Suturing under the microscope can be difficult sometimes, especially in posterior regions, but the accuracy in reapproximation provided by the micro-scope cannot be compared with that provided by the use of loops.Ideally, the suture must keep the soft tissue in place during the time of hea-ling and should not encourage coloni-zation of bacteria. If repositioning has been accurate as it should be, healing occures by primary intention in 24-48 hours and this is the reason why suture removal is indicated after 24-48 hours.1

When left in place for a longer period

of time, the suture has no function and is simply an irritant: soon it will be completely covered by bacteria and will cause inflammation and delayed healing by secondary intention.Many suture materials are commercially available today. Silk is not recommen-ded anymore because it encourages colo-nization by bacteria. Nylon is colonized more slowly, but is too rigid and often patients complain because the suture is irritating the lip or the cheek. Tevdek is a newly introduced suture made of a polytetrafluoroethylene impregnated polyester material. It is very resistant to bacterial colonization and is nonirrita-ting. The suggested size of the suture is 6-0 (Figs. 34 and 35).

ConclusionEndodontic surgery can today be perfor-med with an accuracy and predictabi-

33b 33c

34 35

Advances in Surgical Endodontics

Fig. 28Removal of sutures (Tevdek 6-0) 48

hours after surgery.

Fig. 29Perfect healing with no scar after

three months.

Pag. - 15

Vol. 6, Nr. 1 2003

L’Informatore Endodontico

lity of results that were not possible to reach 10 or 15 years ago. Magnification and illumination together with the new instruments and materials provide a higher success rate than ever before (Fig. 36).Using the microscope, the incision is more accurate, the elevation of the flap is less traumatizing for the soft tissues, the osteotomy and the apicectomy are

Fig. 36A. Preoperative film. B. Two year recall. Note the retrofilling made in Super EBA, 3 mm long, in the long axis and of the same size like the original root canal.36a 36b

more conservative. Using the ultrasonic tips the retropreparation is more precise, coaxial with the root canal, the entire circumference is cleaner, the retrofill is also more accurate, and the exact repo-sitioning of the soft tissue guarantees a perfect healing without any scar. For all these reasons, the surgical procedure is more predictable and the success rate is very high.

Pag. - 16

1) - Carr G.B., Bentkover S.K.: Surgial Endodontics. In: Cohen S. and Burns R.C. Eds. Pathways of the Pulp 7th edn. St. Louis, USA: Mosby, 1998: 608-656.2) - Carr G.B.: Microscopes in Endodontics. Calif. Dent. Assoc. J. 11: 55-61, 1992.3) - Carr G.B.: Ultrasonic Root End Preparation. In:Kim S. ed. The Dental Clinics of North America. Microscopes in Endodontics. Philadelphia, USA. W.B. Saunders Company Vol. 41, N° 3, July 1997, 541-554.4) - Frank A.L. et al.: Long-term evaluation of surgically placed amalgam fillings. J. Endod. 18:391-398, 1992.5) - Kim S.: Principles of Endodontic Microsurgery. In: Kim S. ed. The Dental Clinics of North America. Microscopes in Endodontics. Philadelphia, USA. W.B. Saunders Company Vol. 41, N° 3, July 1997: 481-498.6) - Lemon R.R., Jeansonne B.G., Boggs W.S.: Ferric sulfate hemostasis: effect on osseous wound healing. II. With curettage and irrigant. J. Endod. 19:174-176, 1993.7) - Lemon R.R., Steele P.J., Jeansonne B.G.: Ferric sulfate hemostasis: effect on osseous wound healing. I. Left in situ for maximum exposure. J. Endod. 19:170-173, 1993.8) - Oynick J., Oynick T.: A study of a new material for retrograde fillings. J. Endod. 4:203-206, 1978.9) - Rubinstein R.A.: The Anatomy of the Surgical Operating Microscope and Operating

Positions. In: Kim S. ed. The Dental Clinics of North America. Microscopes in Endodontics. Philadelphia, USA. W.B. Saunders Company Vol. 41, N° 3, July 1997:391-414.10) - Rubinstein R.A.: Endodontic Microsurgery and the Surgical Operating Microscope. Compendium. (18) 7:659-672, 1997.11) - Schwartz R.S. et al.: Mineral trioxide aggregate: a new material for endodontics. Case reports. J. Am. Dent. Assoc. 130:967-975, 1999.12) - Stropko J.J.: Apical microsurgery. Endodontic Communiqué. Boston University, School of Dental Medicine, Summer 1998, 12-14.13) - Torabinejad M., Higa R.K., McKendry D.J., Pitt Ford T.R.: Dye leakage of four root end filling materials: effects of blood contami-nation. J. Endod. 20:159-163, 1994.14) - Torabinejad M., Hong C.U., McDonald F., Pitt Ford T.R.: Phisical and chemical properties of a new root-end filling material. J. Endod. 21:349-353, 1995.15) - Torabinejad M., Watson T.F., Pitt Ford T.R.: Sealing ability of a mineral trioxide aggre-gate when used as a root end filling material. J. Endod. 19:591-598, 1993.

BIBLIOGRAPHY

Advances in Surgical Endodontics