Comparison of Two Root End Filling Techniques during Endodontic Microsurgery of Permanent Anterior Teeth: A Parallel Double Blind Randomized Clinical Trial

Periapical lesions are a common outcome of pulpal infections often leading to the

need for endodontic intervention. While conventional root canal therapy (RCT)

serves as the primary mode of treatment for infected or necrotic pulps, there are

cases where it does not yield the desired therapeutic outcome. When nonsurgical

retreatment fails or is unlikely to succeed, surgical intervention becomes necessary,

making endodontic microsurgery (EMS) a crucial treatment option. This

microsurgical technique, enhanced by magnification tools such as surgical

microscopes and loupes, allows precise surgical intervention to address unresolved

periapical infections. EMS results in high long-term healed (78.3%) and survival

(95.2%) rates

The most critical step of EMS is Root End Filling which comprises of root end

resection, root end preparation and root end filling. Root end resection involves

removal of 3 mm of the root apex, followed by retrograde preparation of canal by

ultrasonic tips and retro-filling it with a biocompatible material. However, it is

more technique-sensitive, as it involves working within a small surgical field under

magnification. Furthermore, there is a risk of the filling material being washed out

before it sets properly due to a lack of effective hemostasis around the root-end

area. Retrograde placement necessitates specialized armamentarium and

preparation of the root-end before placing the filling material carries a risk of

initiating or propagating microcracks, which may eventually result in vertical root

fractures.

There is a concept of ―orthograde technique,‖ which has been proposed. In this,

after completion of biomechanical preparation and achieving a dry canal , the root end

filling material like MTA/Bio dentine is introduced into the root canal space

to about 7 mm from the root apex, followed by obturation of the root canal. The

surgery is performed after 3-5 days. Surgery involves resecting the root end

eliminating the need of retro preparation and retro-filling. This can potentially

reduce postoperative discomfort, including pain and swelling. Wash out of the set.

material is prevented from blood contamination and there is no need of specialized

armamentarium such as ultrasonics reducing the risk of dentinal microcracks.

The efficacy of orthograde technique has been evaluated in few in vitro and animal

studies. Andelin et al (2002) conducted a dye leakage study on 46 extracted teeth

to evaluate the effect of resection on the microleakage of MTA. They found no

significant difference in leakage in teeth with resected MTA or in those with MTA

placed as a retrograde root-end filling material. A micro-CT study (2022) found

no significant difference among the two techniques regarding the total volume of

voids in the root canal of extracted single rooted teeth. Another in vitro study

(2023) found that the retrograde method offered superior marginal adaptation,

while the orthograde method demonstrated greater resistance to dislodgement. An

animal study by Apaydin et al (2003) compared the effects of fresh and set

mineral trioxide aggregate (MTA) on hard tissue healing after peri radicular

surgery. Root canals of 24 mandibular premolars in four 2-year-old beagle dogs

were filled with MTA. After two weeks, half of the roots were resected to the set

MTA, while the other half were prepared ultrasonically and filled with fresh MTA.

Four months later, histomorphometry analysis revealed that fresh MTA led to

significantly higher cementum formation (12/12 vs. 8/12, p = 0.028), but there was

no notable difference in the amount of cementum or bone healing between the two

groups. Another animal study (2011) reported no significant difference in

inflammation or hard tissue healing between the two techniques, though fresh

MTA showed slightly better outcomes.

Despite the presence of favorable in vitro and animal studies, there is no clinical

evidence directly comparing their outcomes of these two techniques. Thus,

conducting a comparative clinical study is essential to assess which method offers

better clinical success and patient outcomes. Hence the proposed randomized

clinical trial aims to compare the outcomes of orthograde and retrograde

placement of root-end filling materials during endondontic microsurgery in

permanent anterior teeth.