Scripta Scientifica Medicinae Dentalis

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Authors: Deyan Neychev, Ivan Chenchev, Dimitar Atanasov

AIM: To assess the incidence of mandibular second molar impaction and the treatment methods for this condition. MATERIALS AND METHODS: A retrospective review of the cases of patients diagnosed with impaction of mandibular molars at the Department of Oral Surgery of the Faculty of Dental Medicine - Plovdiv during the past 11 years was performed. RESULTS: 962 patients with impaction of mandibular molars were operated on in the analyzed period. This diagnosis is relatively rare in second mandibular molars and represents 0.94% of all cases. Most often, diagnosis is based on clinical evidence of missing molars and on panoramic radiographs. In the cases described by us, only surgical treatment was used. CONCLUSION: The treatment of this condition is a challenge which requires an individual approach to each case and an аssessment to determine what treatment approach is to be used - surgical or orthodontic.

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Authors: Elitsa Sabeva, Stefan Peev, Mariya Miteva, Milena Georgieva

The aim of this literature data review was to investigate the influence of the bone density, bone volume, cortical bone thickness and the anatomical area on the primary stability of dental implants. Understanding the effect of the bone quality could help us predict the primary stability and prevent to some extent the poor implant stability by choosing implants of different design, diameter, length or surface modification. Considering the reviewed articles, we have concluded that inserting implants in dense bone of higher quality with thick cortical portion, as well as implant placement in lower jaw could lead to higher primary stability of those implants. To enhance the primary stability in bone of poor quality we suggest the use of implants with such characteristics of the design or dimensions, which are proven to influence the primary stability of the implant in a positive way.

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Authors: Maya Doychinova, Vesselin Kussovski, Slavcho Dimitrov

AIM: The aim of this study is to evaluate and compare the in vitro antimicrobial effect of 2 photosensitizers: FotoSan®medium and ZnPcMe on a biofilm isolate of clinical strain of Streptococci species. MATERIALS AND METHODS: Twelve patients were instructed to stop using any kind of oral hygiene care for 24 hours. Plaque was collected with sterile dental floss, placed in vial containing 3ml of BFS. Tenfold dilution of the suspension was made. Samples of 0.1ml were plated on Mitis Salivarius agar. Bacteria were Gram-stained as well and underwent morphological identification. A bacterial suspension at a density of 106 cells/ml was used. An incubation mixture of 1 ml bacterial suspension (106 CFU/ml) and the corresponding photosensitizer were prepared, achieving a different final concentration of PS. LED light source with a wavelength of 643 nm was used for irradiation. Samples and controls for each tested PS after 24h incubation at 37ºC were reported. RESULTS: The control samples in dark showed a minor antimicrobial effect. Samples of bacterial suspension + PS + light irradiation expressed statistically relevant antibacterial effect on Streptococci species with small differences in the different concentrations and irradiation time used. CONCLUSION: The clinical strain of Streptococci species was susceptible to photodynamic inactivation by the used photosensitizers: FotoSan®medium and ZnPcMe. Full photoinactivation was not observed. Dark toxicity was to be neglected. ZnPcMe should undergo further trials and given the positive photodynamic effect in vitro, be licensed for clinical use. FotoSan®medium should undergo further in vivo and in vitro experiments in order to establish an alternative protocol for caries prevention.

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Authors: Polina Asenova Velcheva, Metodi Zahariev Abadzhiev, Plamen Mihailov Nenkov

INTRODUCTION: The shape of deciduous and permanent teeth can differ morphologically from that which is considered normal, partially or entirely. The variations in tooth shape can be hereditary or caused by a disease or trauma. Gemination, for example, means that two separate morphological units were created by division of the tooth germ. This is an extremely rare condition with a prevalence of 0.2 - 0.5%. AIM: A patient with symptomatic apical periodontitis of a previous endodontically treated tooth 21 was complaining of swelling and pain in the frontal area of maxilla. The basic features and specific appearance of geminated teeth were present - an enlarged mesio-distal diameter of the tooth crown, a groove on the incisal edge, a shallow or deeper groove on the vestibular and oral surface, which divides the tooth into two, usually unequal parts. MATERIALS AND METHODS: Isolation of the tooth was made by OpraDam (Ivoclar Vivadent). For the mechanical debridement of this complex root canal system, we used H-files and rotary files Pro Taper Next till X3 file. Cleaning was done by passive ultrasonic activation and photon-induced photoacoustic streaming by Er-YAG laser of 5.25% NaOCl, 16% EDTA and 2% XX. After double application of Ca(OH)2 as an intracanal medicament for at least 1 week, the sinus track and symptoms were gone. The obturation technique was warm vertical condensation with System B and Obtura(SybronEndo). CONCLUSION: Dentes geminati are extremely rare and difficult to treat endodontically but after proper cleaning, shaping and obturation of this complex root canal system with 2 main root canals with huge isthmus between them and lateral canals we can expect healing.

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Authors: Silviya Dimitrova, Nadia Bibova

The main part of dentists’ work is associated with the operative treatment of dental caries, aiming at the stabilization of the process and restoration of the natural anatomy and function of the teeth with artificial materials. With the emergence of restorative dental medicine came the questions related to the survival rate of the restorations, the reasons for their replacement and the possibilities for control and management of the factors, leading to activation and progression of the carious process. The aim of the literature overview is to study the most common reasons, leading to a decrease of the survival rate of different restorations within the conditions of the mouth cavity. It analyzes factors with direct and indirect importance for the development of secondary caries and the longevity of obturations, such as polymerization shrinkage, accumulation of dental biofilm, micropermeability, marginal adaptation, microgap, etc.

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Authors: Antoniya Pomakova, Nataliya Gateva, Nina Milcheva

INTRODUCTION: The role of simple carbohydrates as a major etiological factor for the carious process is well known. Studies have shown that frequent use of conventional sugar containing medications increases the risk for oral health. Today, a significant proportion of the population chooses alternative medicine and particularly homeopathy for treatment and prophylaxis, considering it effective and safe. However, its influence on oral conditions and its involvement as a risk factor for oral health still remains an under-discussed topic. MATERIALS AND METHODS: The study included 18 volunteer students in dental medicine. An in vitro saliva test with colored strips was used for four consecutive weeks and after intake of three commonly used homeopathic medications. The following entries were registered: baseline value, 15th, 30th and 60th minute following the intake of the respective homeopathic doses. During the first week, the study was carried out without intake of any homeopathic medicine. The data was subjected to statistical analysis. RESULTS: There was a fall in saliva pH following intake of homeopathic medications in all studied patients. The рH reduction was most significant at the 15th minute, and the average drop for the three homeopathic medications was - 0.68, 0.94, 1.07, respectively. On the 30th and 60th minute, the mean pH drop remained the highest for the third drug. CONCLUSION: There was a decrease in saliva pH in all individuals after administration of each medication. In a significant part of the cases the drop was below the critical value of 5.5. The values remained lower than the baseline even an hour following the intake.

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Authors: Tihomir Vasilev, Tsanka Dikova, Dzhendo Dzhendov, Elisaveta Ivanova

The aim of the present paper is to evaluate and compare the strength properties and deformation characteristics of cast and Selective Laser Melted (SLM) Co-Cr dental alloys by using CAD/CAE software. The Solid Works Simulation software is used for simulation of chewing load of the virtual 3D model of a four-part dental bridge. Two Co-Cr dental alloys, cast and SLM were used in this study. During the simulation process by means of linear static analysis the displacements, strains, stresses, and reaction forces under the effect of the applied load were calculated. As a result, the equivalent von Mises stresses, Factor of Safety (FOS) and displacements were evaluated in this study. It was established that the highest values of the equivalent von Mises stresses of cast and SLM bridges are situated in the connectors between the teeth, i.e. the zones with the lowest areas of the cross sections. They are in the range 95-162 MPa, which is lower than the stress limits for the both materials. The minimum FOS of both materials is higher than 1. In the cast bridges it is 1.32-2.64 in the zones with the highest load, while in the SLM samples it is 2.61-5.68. As FOS shows the reserve strength of the material for the applied load, it is obvious that the SLM bridge possesses twice as high reserve strength. This allows optimization of the construction, economy of material and possibility for manufacturing of objects with porous structures.

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Authors: Vassil Svechtarov, Savina Nencheva - Svechtarova

INTRODUCTION: The aim of this study is to evaluate the distribution of the most common comorbid conditions associated with chronic temporomandibular disorders, and the pharmacological agents which play an integral role in the overall management of temporomandibular joint disorders. MATERIALS AND METHODS: A total of 23 articles are included in this comprehensive review of the relevant studies on common comorbid conditions related to temporomandibular disorders. This review provides summarized clinical and online platform based analyses focused on the five most common comorbid conditions and their relevant pharmacological therapy. RESULTS AND CONCLUSION: The majority of the studies show that comorbid conditions may include fibromyalgia, systemic myofascial pain and chronic fatigue syndrome, chronic headaches, migraine, heart arrhythmias, endometriosis, interstitial cystitis, irritable bowel syndrome, lower back pain, sleep disorders - insomnia, autoimmune diseases, sleep apnea, noises and irritation in the ear, vulvodynia and mental disorders. The top comorbid conditions reported from people with TMJ syndrome, regardless of status are: anxiety, depression, insomnia, fatigue and pain.

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Authors: Albena Gencheva, Tihomir Georgiev, Hristina Arnautska, Ivan Gonkov, Petyr Chankov, Kamen Nogalchev

AIM: The aim of this research is to demonstrate the necessity of CBCT – examination for evaluation of the surgical approach of high-risk impacted lower third molars. As “high-risk” we defined lower third molars which have signs of proximity to the mandibular canal seen on standard panoramic radiography. MATERIALS AND METHODS: All patients who had undergone a CT examination between September, 2015 and October, 2016 were reviewed. We included images from cone beam computed tomography made in the Department of Radiologic Diagnostics, University Medical and Dental Centre of the Medical University of Varna. The device used was Planmeca ProMax 3D Max with software for images Planmeca Romexis. We chose 100 images randomly. From these images we selected 39 images with high-risk lower third molars. We examined different signs with which we defined the exact position to the mandibular canal of 60 wisdom teeth and we managed to asses the risk of damaging the IAN during a classical odontectomy of these teeth. In the research we included the panoramic radiographs of 20 patients from these 39 cases. RESULTS: From the examination of the CBCT images we found: 28 lower third molars where the mandibular canal runs apical and has contact; 11 where the mandibular canal runs apical in contact with the tooth and penetration of the apices of the tooth is seen; 10 where the mandibular canal runs buccal with contact; 8 where the mandibular canal runs lingual with contact; 3 where the mandibular canal runs between the roots touching one/both of them. In three of the cases we found severe deviation of the root apices. From the examination of the panoramic radiographs we found: 5 cases with darkening of roots in the apical area; 8 with interruption of the white line (lamina dura) of the mandibular canal; 1 with diversion of the mandibular canal with/without narrowing of the mandibular canal; 6 without any of these three signs. CONCLUSION: The development and rapid commercialization of new technologies like CBCT allows us to have precise images and exact diagnosis of the diseases in the oral and maxillofacial area. Our study confirmed the high diagnostic value of CBCT regarding to precise the position of the lower third molars to the mandibular canal and IAN. This gives the clinician the opportunity to determine which lower third molars are “high-risk” teeth and to choose the best method for surgical treatment.

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Authors: Radosveta Andreeva, Ani Beltcheva

In spite of all the methods of prevention, there still are untreated or improperly treated caries and it’s followed by complications. This often leads to premature loss of teeth. The premature loss of the deciduous teeth depends on different factors such as oral hygiene, traumas, complicated caries. The aim of this study is to compare the OHI-S between children with premature loss and those without premature loss of deciduous teeth. Subject of the monitoring of the clinical research were 140 children between ages 6 and 9. The clinical group consisted of 90 children with prematurely extracted teeth, divided into three groups. The control group consisted of 50 children with intact denture. The oral hygiene status was examined and registered by the Greene-Vermillion index-simplified. There was a statistically significant difference in the OHI-S between the control group (1.86±0.05) and the clinical groups (1.90±0.08 and 2.01±0.05). The children with premature extraction of the primary teeth had higher OHI-S compared to the control group (children without premature extraction of teeth). The third group of children, with prematurely extracted temporary teeth and severe orthodontic deformation, have the highest OHI-S. These results demonstrate the connection between OHI, the orthodontic deformations and the need for prevention.

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Authors: Tihomir Georgiev, Radosveta Andreeva

The premature extraction of primary teeth of children could be done both under local or under general anesthesia. Тhe method of choice depends on different factors. Dental treatment under GA is an effective way to provide necessary dental care to children with special needs, medically-compromised, cognitively immature, highly anxious. The aim of this study is to compare the average age and the average DMFT index of the children with premature extraction of primary teeth treated under local and under general anesthesia. Subject of monitoring of the research were 60 children. The clinical group consists of 30 children with teeth for premature extraction under general anesthesia and the control group consists of 30 children for premature extraction under local anesthesia. The dental status was examined and registered by the DMFT index. The age of the children was filled out in special registration cards. There was a statistically significant difference in the age and the DMFT index between the first group (4.67±0.26 average age) and second group(4.67±0.26 average age ). The DMFT index for the first (clinical) group is 7.18±0.66 and – 5.17±0.33 for the second (control) group. The results show the connection between the carious activity and the need of prevention in younger children.

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Authors: Elitsa Djongova, Tihomir Georgiev, Karen Dzhabalyan, Radosveta Andreeva, Mariana Dimova-Gabrovska

INTRODUCTION: Bony projections on the inner surface of the maxillary sinus are divided into two main groups: exostoses, which are rounded bone structures, and septa, defined as having a pointed end. Bony septa are common anatomical structures and can lead to complications during sinus augmentation procedures. MATERIALS AND METHODS: The study reports a clinical case of a vertical partial basal bony septum, where upon elevation of the sinus membrane, its perforation was observed (size >5 mm). RESULTS: The present study proposes a method of treatment of perforated sinus membranes.The post-surgical period was uneventful. The bone grafting material remained compact in the sinus augmentation site. CONCLUSIONS: The proposed method for the management of perforated sinus membranes can be applied in surgical procedures for perforations > 5 mm in size.

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Authors: Tsanka Dikova, Dzhendo Dzhendov, Iveta Katreva, Diana Pavlova, Maksim Simov, Svetlana Angelova, Metodi Abadzhiev,Tsvetan Tonchev

The purpose of the present paper is to establish experimentally the possibilities of the 3D printer Rapidshape D30 for the manufacturing of standard cubic samples from different types of monomers and to evaluate their geometrical accuracy and roughness. Standard cubic samples with dimensions 5mm х 5mm х 5mm were printed from all the materials, given by the producer, in two ways of dimensional orientation according to the base – horizontally and inclined at 45о. They were manufactured with 3D printer Rapidshape D30, working on a stereolithography principle with LED light. It was established that: ❖ The samples, made of NextDent Surgical Guide, have the highest dimensional accuracy and the lowest deviation interval in both ways of placement. This polymer is characterized with the highest thickness of the polymerization layer – 0.100 mm, but it is transparent, thus ensuring the entire polymerization throughout the depth of the whole layer. NextDent C+B, intended for manufacturing of temporary crowns and bridges, occupies a middle position in comparison to the other 6 materials. ❖ Nearly in all the materials the surface roughness of the cube with horizontal placement is lower than that of the cube printed inclined (average values of Ra 0.46-2.69µm and Ra 1.74-2.77, respectively). ❖ In 3D printing the surface roughness depends on the thickness of the polymerization layer and the inclination to the printing direction. The thicker the polymerization layer and the larger the slope, the higher the surface roughness.

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Authors: Tihomir Georgiev, Karen Dzhabalyan, Radosveta Andreeva, Krasimira Prodanova

INTRODUCTION: Pneumatization of the maxillary sinus can be triggered throughout a patient‘s life. Prior to any sinus floor augmentation procedure, it is imperative to conduct a linear and volumetric assessment of the maxillary sinus. MATERIALS AND METHODS: The CBCT scans in this randomized retrospective study were selected from 120 patients (50 men and 70 women) to analyze the maxillary sinus dimensions both linearly and volumetrically. RESULTS: The volume of the maxillary sinus was significantly increased in the male patients. Statistically significant differences in the volume of the maxillary sinuses were not observed in dentate or edentulous patients. CONCLUSIONS: CBCT imaging for surgical interventions of the maxillary sinus to assess its volume and size has proven to be an indispensable diagnostic tool.

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Authors: Roussi Minev, Ekaterin Minev

The paper describes the basics of the 3D printing technologies for rapid prototyping (RP). It shows the benefits of their utilization in product design and manufacturing of conventional parts and items with medical and other application. The most mature RP principles are presented and compared. Some trends in developing new 3D printers and corresponding materials for micro/nano and biological applications are described. Some modern budget platforms are suggested for technology users. The paper also provides a summary of the main quality issues in the layering technologies as well as methodologies for studying the process capabilities, accuracy and maturity.

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Authors: Stefan Peev, Elitsa Sabeva, Angela Gusiyska, Tihomir Georgiev, Tsvetan Tonchev

INTRODUCTION: The aim of this study was to assess the reduced length implants as an alternative of conventional length implants in combination with bone augmentation. The following criteria were observed: survival rate, marginal bone loss, bleeding on probing. MATERIAL AND METHODS: This study included 186 Straumann Standard Plus implants with dimensions: length of 6 mm and diameter of 4.8 mm. The implants were loaded with non-removable crowns or bridges at least 10 weeks after the implant placement. Depending on the type of the prosthetic option the distribution of the implants was as follows: 83 implants were co-abutments to one more implant with conventional length (8-14 mm); 67 implants were co-abutments to more than one implant with conventional length, 33 implants were loaded with single crowns. RESULTS: The mean period of observation was 5.59 years. The mean marginal bone resorption was 0,224mm. In 12.4% from the cases was registered BOP (bleeding on probing). A correlation was found between the BOP and mean marginal bone resorption. No correlation was found between the values of marginal bone resorption and the type of the prosthetics. The survival rate of the implants in the observation period was 99.5%. CONCLUSION: Тreatment by short implants is a reliable alternative to implants with conventional length with combination of bone grafting procedures. It is less invasive, cost effective and consumes less treatment time.

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Authors: Stefan Peev, Borislav Ivanov, Elitsa Sabeva, Tihomir Georgiev

Introduction: The aim of this investigation was to evaluate the 5-year outcomes regarding presence of intraoperative and postoperative complications and the survival rate of implants placed simultaneously with lower alveolar nerve lateralization or transposition. Material and Methods: implants placement was performed on 34 patients with advanced atrophy of the posterior mandible simultaneously with lower alveolar nerve lateralization or transposition. Transposition was done only in two cases; in the rest of the cases lateralization of lower alveolar nerve was performed. Results: The survival rate at the end of the fifth year after implant placement was 100%. The mean height of residual bone at the region of implant placement was 2.76 mm. The mean marginal bone resorption for at the fifth year was 0.309 mm. In 20.6% of cases a positive BOP (bleeding on probing) was registered. 14.7% of the patients were free of symptoms of NSD (neuro-sensory dysfunction). In the rest of the patients the mean duration of NSD was 2.06 weeks. In 76.4% of patients the symptoms of NSD of nervus alveolaris inf. resolved after the second week. The maximum period of reported NSD was 6 weeks. No permanent NSD occurred. Conclusion: Properly performed lateralization or transposition of the lower alveolar nerve is associated with minimal risk of permanent neuro-sensory dysfunction and providing an opportunity for placement of intraosseal implants in the posterior mandible with high survival rate.

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Authors: Vassil Svechtarov, Savina Nencheva-Svechtarova, Tsvetan Tonchev, Krassimira Prodanova

Introduction: The aim of this study is to evaluate the distribution of the most common etiological factors responsible for the development of chronic temporomandibular disorders, and to test the pain – relief effectiveness of combined gallium-aluminum-arsenide laser (GaAlAs; 785 nm) and superluminiscent diods (SLD; 633 nm) phototherapy (MedX 1100 device) for most common tension and compression pain-related diagnostic subgroups of chronic temporomandibular disorders. Material and methods: This study includes 62 patients - 7 men and 55 women, aged between 21-74 years with clinical signs and symptoms of chronic temporomandibular joint and myofascial pain. Using DC/TMD instruments the most common causative factors were identified, and part of the TMDs assessed were classified to tension and compression related diagnostic subgroups. Trigger point oriented combination of laser (MedX 1100 console with three GaAlAs laser diodes, 785 nm, 3x33 mW, 100 s, 8 J/cm 2 per spot) and SLD red light sessions (633 nm, 200 mW, 300 s, 8 J/cm 2 per spot) was applied for temporomandibular joints and affected muscles. Results and conclusion: Using descriptive analysis and paired samples Student’s t-test, the most statistically manifested pain reduction is found for Arthralgia attributed to Tension-related TMDs (Subluxations, Dislocations, Sprain and strain of joints, ligaments and TMJ – related structures, Flexion-extension injuries; р=0,000001), followed by Myalgia for the same disorders (р=0,000014), followed by Arthralgia attributed to Compression-related TMDs (bruxism, psychosomatic parafunctions, occlusal microtrauma, dentofacial anomalies and malocclusions, р=0,000037), and Myalgia attributed to the same TMDs (р=0,000808). This study shows that combined phototherapy provides statistically significant reduction of pain symptoms for the most common temporomandibular disorders, and that Arthralgia and Myalgia attributed to tension-related disorders are better influenced by combined phototherapy than compression-related ones.

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Authors: Iveta Katreva, Metodi Abadjiev, Simeon Simeonov, Ognjan Tivchev, Maya Doychinova, Tsvetan Tonchev

Purpose: The purpose of this study is to observe, compare and evaluate the effect of two α-adrenomimetic decongestants which are clinically approved nasal and eye drops – 0.05% xylometazoline hydrochloride and 0.05% tetrahydrozoline hydrochloride, when applied as chemical agents for chemo-mechanical retraction of free gingiva prior to impression making in fixed prosthodontics. Materials and methods: The study includes 90 prepared abutment teeth indicated for fixed prosthodontic treatment. α-adrenomimetic decongestants in the composition of 2 approved for clinical usage nasal and eye drops commercial products were applied as chemical agents for gingival retraction – Xylometazoline (0.05% xylometazoline hydrochloride) and Visine (0.05% tetrahydrozoline hydrochloride). Ultrapak retraction cord of four different sizes impregnated with the investigated chemical agents was used. Two steps twolayered impressions with polyvinyl and polydimethylsiloxane were taken from the prosthetic fields. Impression sections were fabricated and studied under microscope. Results: The low viscosity polyvinyl and polydimethyl siloxane layers tend to penetrate deeper in the gingival groove after chemo-mechanical retraction with Xylometazoline compared to the second group impressions fabricated after Visine retraction. Conclusion: The conducted testing demonstrated that effective retraction of the free marginal gingiva is possible to obtain with α-adernomimetic decongestants. 0.05% xylometazoline hydrochloride (Xylometazoline) provides better results in comparison to the eye decongestant drops 0.05% tеtrahydrozoline hydrochloride (Visine).

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Authors: Elitsa Deliverska, Assya Krasteva

Epidermolysis bullosa (EB) represents a rare chronic autoimmune subepidermal vesiculobullous disorder that affects the skin and mucosa and is characterized by blistering and mechanical fragility of the skin. The most recent classification recognizes four major EB groups: intraepidermal EB (Simplex), junctional EB, dermolytic EB (Dystrophic), and mixed EB (Kindler syndrome). Kindler syndrome is a rare genodermatosis with clinical features of trauma-induced blistering, poikiloderma, skin atrophy, mucosal inflammation and varying degrees of photosensitivity. Although Kindler syndrome is classified as a subtype of epidermolysis bullosa, it has distinct clinicopathological and molecular abnormalities. The clinical features of the syndrome have been annotated by different authors but definite criteria to confirm the diagnosis have not yet been generally accepted.

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Authors: Assya Zaharieva Krasteva

INTRODUCTION: Sturge-Weber syndrome is a rather uncommon congenital condition that occurs sporadically, characterized by the combination of ipsilateral angiomatous lesions of the face, oral soft tissues, and jaws with venous angioma of the leptomeninges over the cerebral cortex. However, the main clinical features of this syndrome are facial vascular cutaneous naevus, usually unilateral, which often follows the outline distribution of the trigeminal nerve. MATERIAL AND METHODS: We report two cases of 7-year-old and 11-year-old girls with diagnosis Sturge-Weber syndrome, emphasizing the oral and extraoral manifestation related to the syndrome. The patients were presented with a cutaneous vascular nevus on the face during early childhood as well as epileptic crisis episodes, with no ophthalmic alterations. CONCLUSION: Sturge-Weber syndrome commonly affects the oral cavity therefore, it is important for the dentists’ knowledge in order to provide an adequate dental management without complications.

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Authors: Tsvetelina Borisova-Papancheva, Vladimir Panov, Stefan Peev, Georgi Papanchev

The aim of this study is to describe different root-end filling materials according to the literature and to compare their antibacterial activity, sealing ability, biocompatibility and microleakage. The purpose of a root-end filling is to establish a seal between the root canal space and the periapical tissues. A number of materials have been suggested for use as root-end fillings, including gutta-percha, amalgam, Cavit, intermediate restorative material (IRM), super EBA, glass ionomers, composite resins, carboxylate cements, zync phosphate cements, zinc oxide-eugenol cements and mineral trioxide aggregate (MTA).

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Authors: Georgi Papanchev, Tihomir Georgiev, Stefan Peev, Hristina Arnautska, Nedyalka Zgurova, Tsvetelina Borisova-Papancheva, Elitza Dzhongova

Maxillary sinus floor augmentation has been used for occlusal rehabilitation with prosthetic appliances installed over dental implants in the posterior maxilla despite the fact that this region often presents loss of alveolar bone and increased maxillary sinus pneumatization, particularly when all of the molars are absent. The shortage and quality of the remaining bone often implies a challenge when rehabilitating with dental implants. Different kinds of grafts have been used in an endeavour to solve these problems. The aim of this study is to find out if there is a significant difference in the bone formation between the 6th- and the 9th - month periods after sinus lift grafting with a calcium- phosphate paste (Maxresorb inj. (Botiss Dental, Berlin, Germany)). For this purpose а bilateral sinus lift has been made by own methodology. Results showed no significant difference in the percentage of newly formed bone in the sixth and the ninth month, which warrants the dental implants to be placed on the sixth month post-sinus lifting.