Use of Ultrasound Investigation in the Treatment Plan of Apical Surgery Relapse

Among the determining factors of chronical periodontitis is listed bacterial microbiota, especially Gram-negative bacteria that induce bone resorption due to lipopolysaccharides (LPS) and Gram-positive bacteria that damage the dental pulp and the periapical tissues through the lipoteichoic acid (LTA) [1]. The treatment of apical periodontitis is performed by mechanical instrumentation and thorough irrigation with antimicrobial substances, followed by the sealing of the root canals. Although the endodontic field seems to emerge with more effective substances used for disinfection and mechanical instrumentation to improve the clinical outcome, the residual endotoxins in the root canals lead to relapse or to complications [2]. The complications such as periapical periodontitis is treated by root-end surgery consisting in the removal of the tooth’s apex, followed by retrograde obturation. The association of an oral antibiotic such as ciprofloxacin, ofloxacin or azithromycin is more efficient in the eradication of the microbial infection compared to large-spectrum antibiotics such as penicillin [3]. Cystic periapical infections are less likely to heal after endodontic treatment due to the fact they are self-sustaining even in the absence of the microbial infection [4].


Introduction
Among the determining factors of chronical periodontitis is listed bacterial microbiota, especially Gram-negative bacteria that induce bone resorption due to lipopolysaccharides (LPS) and Gram-positive bacteria that damage the dental pulp and the periapical tissues through the lipoteichoic acid (LTA) [1]. The treatment of apical periodontitis is performed by mechanical instrumentation and thorough irrigation with antimicrobial substances, followed by the sealing of the root canals. Although the endodontic field seems to emerge with more effective substances used for disinfection and mechanical instrumentation to improve the clinical outcome, the residual endotoxins in the root canals lead to relapse or to complications [2]. The complications such as periapical periodontitis is treated by root-end surgery consisting in the removal of the tooth's apex, followed by retrograde obturation.
The association of an oral antibiotic such as ciprofloxacin, ofloxacin or azithromycin is more efficient in the eradication of the microbial infection compared to large-spectrum antibiotics such as penicillin [3]. Cystic periapical infections are less likely to heal after endodontic treatment due to the fact they are self-sustaining even in the absence of the microbial infection [4].
Complications after endodontic treatment mainly appear as a consequence of forwarding beyond the apex the gutta-percha, root-filling material, or other foreign bodies, such as paper points, amalgam, endomethasone, calcium salts [4]. After establishing the diagnosis of the periapical pathology based on clinical and radiological examination (bidimensional radiographies, tridimensional Computer Tomography-CT, Magnetic Resonance Imaging-MRI or Ultrasonography), the histological examination of the biopsy specimens is useful to exclude a malignancy. Rud & Moller presented a radiographical classification of the periapical tissue after surgery, recommending a minimum of one-year follow-up, ranging from Group 1-complete healing, to Group 4unsatisfactory healing-failed intervention [5].

ARTICLE INFO abstract
Consecutive to endodontic treatment, the periapical infection, either acute or chronic, is a frequent disease in oral pathology. The two clinical features of periapical infection are granulomatous and cystic, characterized by bone loss, root resorption and impairment of tooth implantation. In current practice, the diagnosis of bone resorption is established using bidimensional and tridimensional radiological examinations. The present case report presents the fibrous exophytic wound healing as a rare complication of apicoectomy and shows the advantages of using ultrasonography in determining the size and nature of maxillary mucosa exophytic structures.

Discussion
Literature states that regarding apical periodontitis, the specimens sent to histopathogical examination are mostly granulomatous inflammation (due to foreign bodies), benign central giant-cell granulomas, fibro-osseous dysplasia, odontogenic keratocyst and periapical pathologies caused by infections (actinomycosis, histoplasmosis) [6]. Over the time, more accurate radiological methods such as MRI, CT and CBCT were used to investigate the periapical pathologies, especially cysts and granulomas, [7][8][9]. These methods are very useful in revealing bone resorption and soft tissue changes. In our case, after the first and second surgical interventions, a fibrous healing of both of the periapical bone and vestibular mucosa of the surgical situs were observed. The ultrasound color Doppler investigation showed no vascularization of the exophytic structure. This might be due to a fibroblastic hyperplasia induced by the healing process itself and the proinflammatory mechanisms involved. In dentistry, ultrasonography has been used to diagnose periapical cysts and granulomas, either as primary pathology or consecutive to endodontic treatment, and the postoperative healing.
Ultrasonography has the advantage of providing in a nonionizing manner, the size and nature of the analyzed structures [10][11][12]. In the presented case, the excised specimen had a larger size in mesiodistal direction compared with the ultrasound measurements, but with a similar shape in frontal section. The mesial extension showed a higher hypoechogenicity compared with the exophytic fibrous structure adjacent to tooth 2.3, which might be due to the dense fibrous hyperplasic and hyalinized structure of the tissue.

Conclusion
Ultrasonography is a non-invasive, nonionizing, painless, repetitive and real-time imaging method that can be used for examinations both the soft and the hard tissues. It could be taken into consideration as a more suitable investigation compared with the current radiological assays, due to the measurement and Doppler functions, which allows the assessment of the vascularization pattern of oral cavity lesions and periapical pathological tissues. This represents an advantage in setting a treatment protocol, foreseeing possible complications and their management. The assessment of ultrasonography is an attractive and useful approach and should be considered to be implemented as an area of expertise in dentistry and oral surgery practice.