Healing After Endodontic Microsurgery Using a Rotary Bur Versus Piezoelectric Unit for Osteotomy and Root Resection

The aim of this study is to prospectively compare postsurgical healing after the use of microsurgical technique to eliminate apical pathology, either by use of rotary burs for osteotomy and root resection, or by use of piezoelectric surgery for the same clinical procedures. Null hypothesis is that there is no difference in healing and buccal bone thickness reformation between the two surgical procedures Another purpose of the study is to prospectively evaluate healing after the application of a novel buccal bone preservation technique, called the 'bone window' technique. The technique will be applied in a subgroup of patients on maxillary and mandibular premolar and molar teeth with an intact buccal cortical bone and healing and buccal bone reformation will be assessed at follow up. Null hypothesis in this part, is that there is no difference in healing and buccal bone preservation between osteotomy with a bur and the 'bone window' technique.

Inclusion criteria

• Age 18 years and older consenting to the surgical procedure as well as agreeing to preoperative, postoperative and at least one follow-up CBCT evaluation after 12 months
• Noncontributory medical history (American Society of Anesthesiologists class I and II)
• A history of previous endodontic treatment with radiographic presence of apical periodontitis
• A true endodontic lesion: microsurgical classification A, B, or C according to Kim and Kratchman, 2006.
• Lesion size 10 mm or smaller in diameter measured on preoperative CBCT
• Coronal restoration should be present at the time of follow up examination.

Exclusion criteria

• Nonconsenting patients and patients younger than 18 years of age
• Medical history with American Society of Anesthesiologists class III to V
• Insufficient coronal restoration
• Nonrestorability or traumatized teeth
• Teeth with microsurgical classification D, E, or F according to Kim and Kratchman, 2006.
• Mobility I or higher
• Radiographic presence of nonapical root resorption
• Teeth with a vertical root fracture or coronal/ midroot perforation
• Lesion size larger than 10 mm in diameter measured on preoperative CBCT
• Use of bone graft material for regeneration