Current Organizations / Institutes

The organizations/institutes from the scholar's latest article


Alexander Bonchev has a total of 29 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    Clinical Observations on Postless Fiber-Reinforced Composite Restorations in Endodontically Treated Teeth with Immediate Pre-Endodontic Dentin Sealing and an Internal Adhesive Ferrule: A Case Series

    by Alexander Bonchev

    Background: Traditional reliance on intraradicular posts for the restoration of root-filled teeth is decreasing due to advances in adhesive dentistry. Immediate pre-endodontic dentin sealing (IPDS) aims to protect dentin during endodontic procedures and improve adhesive outcomes. For teeth with minimal remaining structure and absent ferrule, internal adhesive ferrule approaches using fiber-reinforced composites or fiber mesh offer an alternative to posts. Methods: Four endodontically treated teeth with severely reduced coronal structure were restored using the IPDS protocol, reinforcement with an internal adhesive ferrule ring and fiber composites, and postless adhesive build-ups. Clinical and radiographic assessments were performed up to 2.5 years post-treatment. Results: All teeth remained asymptomatic, with stable periodontal and periapical conditions. Restorations maintained structural integrity and favorable adhesive performance. Conclusions: Within the limitations of this small case series, the IPDS approach combined with fiber-reinforced postless restorations showed favorable short-term clinical outcomes. Given the small sample size, case heterogeneity, and lack of a control group, these observations should be considered preliminary, and well-designed, long-term controlled studies are required to confirm the durability and broader applicability of this technique.

  • Open Access

    Changes in Oral Mucosa Associated with Melanotan II Injections: A Case Report

    by Alexander Bonchev

    This case report presents a three-month follow-up of a patient who self-administered Melanotan II injections over a period of 64 days with the goal of achieving a deeper tanning effect. Melanotan II is an unlicensed synthetic peptide analog belonging to the melanocortin hormone family. It acts primarily by activating melanocortin 1 receptors on melanocytes, stimulating eumelanin production and resulting in skin pigmentation independent of sun exposure. Despite its popularity, particularly through promotion on social media, Melanotan II remains unregulated, and its use is associated with a range of potential adverse effects. During the initial intraoral examination, brown pigmentation was observed on the attached gingiva in both the maxillary and mandibular arches. The lesions were almost symmetrically distributed, with a more intense coloration in the anterior region of the lower jaw. Additional pigmented areas with irregular shapes and poorly defined borders were noted on the left and right buccal mucosa. At the one-month follow-up after discontinuation of the injections, the buccal mucosal pigmentation had nearly disappeared. However, at the three-month follow-up, gingival pigmentation persisted, though with visibly reduced intensity. To date, there is a lack of published data specifically addressing the timeline for resolution of oral pigmentation associated with Melanotan II use, making this case a valuable contribution to the limited existing literature on the subject.


  • Open Access

    Clinical Management of Cervical Restorations with Closing Gap Technique: A Follow-Up of Two Cases

    by Alexander Bonchev

    Background: Cervical restorations remain clinically challenging due to complex anatomy, limited enamel availability, and difficulties in achieving reliable adhesion at dentin or cementum margins. Polymerization shrinkage and marginal leakage are frequent causes of failure. Although the Closing Gap Technique has been proposed to improve marginal adaptation in cervical restorations, evidence supporting its medium- to long-term clinical performance is limited. The aim of this case report was to evaluate the clinical effectiveness of the Closing Gap Technique in the restoration of carious and non-carious cervical lesions. Materials and Methods: Two patients presenting with cervical lesions were treated using the Closing Gap Technique. One case involved carious cervical lesions, while the second included multiple non-carious cervical lesions. Restorations were performed following an enamel-anchored incremental layering protocol with resin composite. Clinical evaluations were conducted at 8 years (case #1) and 2 years (case #2) post-treatment, respectively. Results: Both cases demonstrated favorable clinical outcomes at follow-up. The restorations exhibited good marginal integrity, satisfactory esthetics, absence of marginal discoloration, no secondary caries, and no signs of debonding. The only minor defect observed was slight chipping of one of the restorations. Conclusions: Within the limitations of this case report, the Closing Gap Technique showed stable and predictable medium- and long-term clinical performance, supporting its use as a viable restorative approach for managing cervical lesions in daily clinical practice.

  • Open Access

    Non-Surgical Management of Apical Fenestration Associated with Apical Periodontitis in a Tooth with an Open Apex: A Case Report

    by Alexander Bonchev

    Background and Clinical significance: Apical fenestration is a rarely reported clinical finding that may be associated with apical periodontitis. However, its diagnosis can often be complicated by overlapping clinical and radiographic features. While management traditionally involves a combination of endodontic and surgical interventions, there is limited documentation regarding successful outcomes achieved through non-surgical treatment alone. Therefore, further reporting and investigation of such cases are warranted to enhance clinical understanding and inform decision-making. Case Presentation: This case report describes the non-surgical management of a 20-year-old patient presenting with symptomatic apical periodontitis and a labial apical fenestration in a previously treated maxillary left central incisor (tooth #21) exhibiting an open apex. Diagnosis was confirmed using cone-beam computed tomography (CBCT), which revealed a bone defect in the facial cortical plate. The treatment protocol involved conservative canal debridement, intracanal placement of calcium hydroxide, and final obturation using an apical plug of calcium silicate-based hydraulic cement (CSBHC) and the monoblock technique. Over a follow-up period of two years and eight months, clinical and radiographic assessments demonstrated resolution of symptoms, healing of the sinus tract, and complete regeneration of the buccal cortical bone. Conclusions: This case highlights the potential for complete healing of apical fenestration associated with apical periodontitis in an open apex tooth through non-surgical endodontic treatment alone.

  • Open Access

    Polycarboxy/Sulfo Betaine—Calcium Phosphate Hybrid Materials with a Remineralization Potential

    by Diana Rabadjieva, Rumiana Gergulova, Konstans Ruseva, Alexander Bonchev, Pavletta Shestakova, Marin Simeonov, Radosveta Vasileva, Dragomir Tatchev, Rositsa Titorenkova, Elena Vassileva

    Biomacromolecules control mineral formation during the biomineralization process, but the effects of the organic components’ functionality on the type of mineral phase is still unclear. The biomimetic precipitation of calcium phosphates in a physiological medium containing either polycarboxybetaine (PCB) or polysulfobetaine (PSB) was investigated in this study. Amorphous calcium phosphate (ACP) or a mixture of octacalcium phosphate (OCP) and dicalcium phosphate dihydrate (DCPD) in different ratios were identified depending on the sequence of initial solution mixing and on the type of the negative functional group of the polymer used. The more acidic character of the sulfo group in PSB than the carboxy one in PCB determines the dominance of the acidic solid phases, namely, an acidic amorphous phase or DCPD. In the presence of PCB, the formation of ACP with acicular particles arranged in bundles with the same orientation was observed. A preliminary study on the remineralization potential of the hybrid material with the participation of PSB and a mixture of OCP and DCPD did not show an increase in enamel density, contrary to the materials based on PCB and ACP. Moreover, the latter showed the creation of a newly formed crystal layer similar to that of the underlying enamel. This defines PCB/ACP as a promising material for enamel remineralization.


  • Open Access

    Bioinspired Remineralization of Artificial Caries Lesions Using PDMAEMA/Carbomer/Calcium Phosphates Hybrid Microgels

    by Alexander Bonchev, Marin Simeonov, Pavletta Shestakova, Radosveta Vasileva, Rositsa Titorenkova, Anton Apostolov, Elena Dyulgerova, Elena Vassileva

    Dental caries remains one of the most prevalent bacterium-caused chronic diseases affecting both adults and children worldwide. The development of new materials for enhancing its remineralization is one of the most promising approaches in the field of advanced dental materials as well as one of the main challenges in non-invasive dentistry. The aim of the present study is to develop novel hybrid materials based on (PDMAEMA)/Carbomer 940 microgels with in situ deposited calcium phosphates (CaP) and to reveal their potential as a remineralization system for artificial caries lesions. To this purpose, novel PDMAEMA/Carbomer 940 microgels were obtained and their core–shell structure was revealed by transmission electron microscopy (TEM). They were successfully used as a matrix for in situ calcium phosphate deposition, thus giving rise to novel hybrid microgels. The calcium phosphate phases formed during the deposition process were studied by X-ray diffraction and infrared spectroscopy, however, due to their highly amorphous nature, the nuclear magnetic resonance (NMR) was the method that was able to provide reliable information about the formed inorganic phases. The novel hybrid microgels were used for remineralization of artificial caries lesions in order to prove their ability to initiate their remineralization. The remineralization process was followed by scanning electron microscopy (SEM), X-ray diffraction, infrared and Raman spectroscopies and all these methods confirmed the successful enamel rod remineralization upon the novel hybrid microgel application. Thus, the study confirmed that novel hybrid microgels, which could ensure a constant supply of calcium and phosphate ions, are a viable solution for early caries treatment.


  • Open Access

    EVALUATION OF THE APICAL SEAL AFTER POST SPACE PREPARATION: IN VITRO STUDY

    by Elka Radeva, Desislava Tsanova-Tosheva, Alexander Bonchev, Rumen Radev, Mario Gruncharov, Martin Vloka, Slavka Dimitrova, Valena Ivancheva