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INTRODUCTION: Due to COVID-19, innovative, virtual educational methods are being developed to provide students with learning experiences comparable to established clinical practices. Our objective was to produce the Periodontal Senior Case Clinical Challenge (PSCCC) that would provide fourth-year students an alternative for senior case presentations and would be a formative assessment for which student opinions would be provided and analysed. The PSCCC would utilise an online, case-based, written, clinical assessment and follow-up, structured discussion to challenge students to demonstrate ability to apply didactic periodontal knowledge to patient-based experiences. We hypothesised the PSCCC would provide effective learning and a formative assessment. MATERIAL AND METHODS: Relevant didactic resources were distributed to 48 students for independent review. The PSCCC was delivered in two sections, (1) a case-based assessment via a virtual classroom with written student responses, and (2) oral discussions conducted via virtual meetings that were moderated and assessed by ten periodontists, with the collaboration of nine residents. A voluntary six-statement survey was used to evaluate the students' opinions of the PSCCC. The scores for 75% (36/48) of students who participated were evaluated for statistical and clinical importance. RESULTS: The value of our PSCCC was supported by 91.7% (33/36) of the analyses (p

Hydraulic calcium silicate-based (HCSB) or “bioceramic” sealers are widely used for root canal obturation and rapidly gaining popularity among general practitioners and endodontists. The premixed or fifth-type HCSB materials can be used with all root canal obturation techniques, such as cold lateral and warm vertical compaction or a single-cone technique. Meanwhile, the fourth-type HCSB sealers are sensitive to heat and desiccation, therefore suitable for cold root canal obturation techniques. Although all obturation techniques are equally effective and not superior to each other, the single-cone obturation technique is easier to apply, and is more time-consuming and clinically appealing in modern endodontics. This article will introduce and discuss the most popular HCSB sealers and root canal obturation techniques used in conjunction with these materials.

The present study evaluated the effect of ultrasonic agitation on the porosity distribution of BioRoot RCS/single gutta-percha cone (BR/SC) and MTA Flow (MF) root canals fillings used as apical plugs in moderately curved and apically perforated roots. Eighty mesial root canals of mandibular first molars were enlarged up to ProTaper NEXT X5 rotary instrument 2 mm beyond the apical foramen, simulating apical perforations. Specimens were randomly divided into four experimental groups (20 canals per group) according to the material and technique used for root canal obturation: BR/SC, BR/SC with ultrasonic agitation (BR/SC-UA), MF and MF with ultrasonic agitation (MF-UA). The ultrasonic tip was passively inserted into the root canal after the injection of flowable cement and activated for 10 s. The specimens were scanned before and after obturation with a high-resolution micro-computed tomography scanner, and the porosity of the apical plugs was assessed. The differences between groups were analyzed using the Kruskal-Wallis and Mann-Whitney tests, with the significance level set at 5%. None of the obturation materials and techniques used in this study was able to provide a pore-free root canal filling in the apical 5 mm. Considerably higher percentages of open and closed pores were observed in the MF and MF-UA groups, with the highest porosity being in the MF-UA group (p &lt, 0.05). No significant differences were observed between the BR/SC and BR/SC-UA groups, where the quantity of open and closed pores remained similar (p &gt, 0.05).

The objective of this study was to assess the porosity distribution of BioRoot RCS/single gutta-percha point root-canal fillings performed by a general dental practitioner and endodontist. Fourteen plastic models of maxillary premolars with two roots were selected and shaped with HyFlex EDM instruments to a size 40/0.04 taper and randomly divided into two experimental groups. A total of 14 canals in each group were obturated by two different operators with one HyFlex EDM size 40 gutta-percha point and BioRoot RCS sealer. The specimens were scanned with a high-resolution micro-computed tomography scanner, and the porosity of the fillings at the coronal, middle, and apical thirds of the root canals was qualified and quantified. The differences between groups and root-canal thirds were compared using Mann–Whitney, Friedman, and Wilcoxon tests with the significance level set at p &lt, 0.05. The highest number of pores was observed in the apical third of root-canal fillings in both groups, however, the porosity distribution between the two groups was not significantly different in the apical and middle thirds (p &gt, 0.05). Statistically significant differences were determined only in the coronal third (p &lt, 0.05). The predominance of open pores was detected in all root-canal thirds and groups, with no significant differences in the number of open pores between the coronal and middle thirds (p &gt, 0.05).

The knowledge of the internal anatomy of the root canal system and its variations has a significant impact on the quality and outcome of endodontic treatment. The aim of this study was to evaluate the three-dimensional anatomical features of the root canals of mandibular first molars by using micro-computed tomography.Sixty mandibular first molars were scanned using a high-resolution micro-computed tomography device. The 2- and 3-3-dimensional anatomical features of each root such as distance between anatomical apex and apical foramen, the number of the lateral canals and configuration of the isthmuses, were evaluated.The average distance between the anatomical apex and the apical foramen was 1.047 mm. Lateral canals were present in 85% of the cases, while 76% of them were localized in the apical third of the root. 80% of the mesial roots had isthmuses and the configuration of Type I, according to the Fan classification, was the most prevalent (35%).The results of this study revealed the wide variations of internal root canal anatomy in mandibular first molars, including lateral canals and isthmuses. A clinician should always consider the possible difficulties of anatomical variations before starting root canal treatment, to select the best and optimal treatment strategies.

The present study evaluated the obturation quality of root canals filled with BioRoot RCS sealer and single gutta-percha point by undergraduate student (US), postgraduate student (PS) and endodontist (ED). Twenty-one plastic models of upper premolars were enlarged with HyFlex EDM instruments to a size 40/0.04 taper and randomly divided into three groups (7 teeth/14 canals per group): US, PS and ED. After the obturation of root canals with BioRoot RCS and one HyFlex EDM size 40 gutta-percha point, plastic models were scanned using micro-computed tomography scanner (µCT) SkyScan 1272 at isotropic resolution of 10 µm. The porosity distribution was evaluated separately for the apical, middle and coronal thirds. The Kruskal–Wallis, Mann–Whitney, Friedman and Wilcoxon tests with the significance level set at 5% were used for data analysis. The µCT evaluation revealed open pores being the dominant type of porosity in all experimental groups and root canal thirds, with the highest percentage of pores in the apical third of root canal fillings. The quality and homogeneity of single cone root canals fillings remained similar between the groups in the apical and middle thirds (p &gt, 0.05). Significant differences were observed only in the coronal third (p &lt, 0.05).

Pulpectomy in deciduous teeth involves endodontic access opening, root canal debridement and obturation with an appropriate filling material. EndoREZ (ER) is the urethane dimethacrylate-based filler, which can be used for root canal obturation in permanent and primary teeth. This observation aimed to evaluate the behavior of the ER as a filler in root canals of two primary molars after the physiological resorption process using the scanning electron microscopy (SEM) and micro-computed tomography (µCT) in second lower molars after their natural exfoliation. The SEM analysis revealed a non-uniform, porous and lacunary structure of ER, visually similar to the resorbed surface of the dentine. The µCT observations demonstrated the differences in the resorption level of the root and material surfaces. The preliminary observations suggest that ER is resorbed faster than root tissues and can therefore be a suitable material for the root canal filling in primary teeth. However, more investigations are needed to support these preliminary findings.

The better understanding of the clinically important behavioral features of new instrument systems has an important significance for the clinical endodontics. This study aimed to investigate the shaping and centering ability as well as cyclic fatigue resistance of HyFlex CM (CM), HyFlex EDM (EDM) and EdgeFile (EF) thermally treated nickel&ndash, titanium (NiTi) endodontic instrument systems. Sixty curved root canals of the mesial roots of mandibular molars were randomly assigned into three groups (n = 20) and shaped using CM, EDM and EF files up to the size 40 and taper 04 of the instruments. &micro, CT scanning of the specimens before and after preparation was performed and the morphometric 2D and 3D parameters were evaluated in the apical, middle and coronal thirds of root canals. In each group, 40.04 instruments (n = 20) were subjected to the cyclic fatigue resistance test in artificial root canals at 37 &deg, C temperature until fractures occurred, and the number of cycles to failure (NCF) was calculated. The fractographic analysis was performed using a scanning electron microscope, evaluating topographic features and surface profiles of the separated instruments. The one-way analysis of variance with post hoc Tuckey&rsquo, s test was used for statistical analysis of the data, the significance level was set at 5%. All systems prepared the comparable percentage of root canal surface with the similar magnitude of canal transportation in all root thirds (p &gt, 0.05), but demonstrated significantly different resistance to cyclic fatigue (p &lt, 0.05). The most resistant to fracture was EF, followed by EDM and CM. The length of the fractured fragments was not significantly different between the groups, and fractographic analysis by SEM detected the typical topographic features of separated thermally treated NiTi instrument surfaces.

The newer types of hydraulic calcium silicate–based materials (Types 4 and 5) are rapidly gaining popularity among clinicians. These materials are modified by additives which enhance their performance and also presented in different consistencies thus easier to use. Due to their exceptional biological, physicochemical properties, superior handling characteristics, and simplified clinical application, these materials have come into widespread use for the management of endodontic complications. Management of immature apices, repair of root perforations, root resorption defects, filling the retrocavities in endodontic surgery, and other treatment procedures can be performed using these materials with the similar success rates as mineral trioxide aggregate (MTA). This chapter will introduce and discuss the most popular hydraulic calcium silicate–based repair materials and techniques, used for management of endodontic complications.

The fourth and fifth types of hydraulic calcium silicate-based sealers are rapidly gaining popularity among clinicians due to their exceptional biological, physicochemical properties, and simplified clinical application. These materials can be used with all root canal obturation techniques, such as cold lateral or warm vertical compaction techniques, and especially a single-cone technique. Although all obturation techniques are equally effective and not superior to each other, the single-cone obturation technique is easier to apply, is more time-consuming, and clinically appealing in modern endodontics. This chapter will introduce and discuss the most popular hydraulic calcium silicate–based sealers and root canal obturation techniques used in conjunction with these materials.

To identify the prevalence and determinants of dental trauma in permanent anterior teeth among 11- to 13-year-old schoolchildren, to compare self-reported dental trauma rates with clinical examination trauma rates, and to examine mouthguard use among children engaged in contact sports.A probability sampling scheme was used to recruit schools, with all 6th grade children in the selected schools invited to participate. A total of 2621 caregiver consent forms were sent, of which 807 were returned (31%). Caregivers were asked four trauma-related questions. Clinical examinations included assessment of dental trauma experience (trauma index with five severity codes), lip competence and incisal overjet. Child- and tooth-level analyses were performed.Clinical evidence of dental trauma was found in 52% of participants, 13% self-reported dental trauma, and 7% of children did not remember the occurrence of any trauma. The two most frequently self-reported reasons of dental injury were falls or collisions with objects (63%) and sport/leisure activities (32%). Nearly half of the more severe dental injuries did not receive the necessary treatments. One-third of schoolchildren participated in contact sport activities, but only 3% always used mouthguards. There was a substantial difference between the clinical and self-reported findings. Logistic regression analyses revealed no statistically significant associations between dental trauma experience and the potential determinants studied: gender, lip coverage and overjet.In this study, traumatic dental injuries were observed with 52% prevalence. A substantial discrepancy between self-reported and clinical findings was observed.

Objective: The aim of this study was to compare the impact of treatment procedures on roots previously treated with resorcinol–formaldehyde resin and analyze the effectiveness of dye and magnification for the detection of dentin cracks. Materials and methods: Distal roots of 80 permanent first mandibular molars with a single canal were sectioned at 3 mm and 9 mm from the anatomical apex. Two groups were formed according to the method used for root canal penetration: group 1 (K-file and Pro Taper instruments) and group 2 (Ultrasound with Pro Ultra and Pro Taper files). Before and after the completion of procedures, photographs of the roots were taken for examination for cracks or/and infraction lines with two levels of magnification and with or without a dye. Results: In groups 1 and 2, either with dye or without it, there were statistically significant differences (P &lt, 0.001) with more fractures observed in the coronal than in the apical part of specimens. Statistically significant proportional differences regarding the location of fractures were observed at both magnifications. When the dye was used, there were no statistically significant differences between the two magnifications in the detection of cracks. In the specimens where the dye was not used, differences between the groups were statistically significant at both magnifications with more complete and intra-dental fractures observed in group 2. Conclusions: Retreatment methods had a damaging effect on the root dentin of teeth previously treated with resorcinol–formaldehyde resin. At magnification ×16, the efficacy of using the dye for the detection of cracks was higher than detection without the dye.

The present study evaluated the porosity distribution of BioRoot RCS/single gutta-percha point (BR/SC) and MTA flow (MF) fillings, which were used as plugs for the apical perforation repair in curved canals of extracted mandibular molars using micro-computed tomography (&mu, CT). Forty mesial root canals of mandibular first molars were shaped with ProTaper NEXT X1&ndash, X5 files 2 mm beyond the apex to simulate apical perforations that were randomly divided into two groups (n = 20) according to the material and technique used for the apical plug: BR/SC or MF. The specimens were scanned before and after canal filling at an isotropic resolution of 9.9 &mu, m. The volumetric analysis of voids in the apical 5 mm of the fillings was performed. Data were analyzed using one-way ANOVA with Bonferroni correction (p &lt, 0.05). Micro-computed tomography (&micro, CT) evaluation revealed significant differences between the groups in terms of porosity: the total volume and percentage volume of voids was lower in the BR/SC group in comparison with the MF group (p &lt, 0.05), with the predominance of open pores in both groups. Neither of the materials and/or application techniques were able to produce void-free root fillings in the apical region of artificially perforated curved roots of mandibular molars.

Dental implant abutment and prosthetic materials, their surface treatment, and cleaning modalities are important factors for the formation of a peri-implant soft tissue seal and long-term stability of bone around the implant. This study aimed to investigate the influence of a polymeric material surface cleaning method on the surface roughness, water contact angle, and human gingival fibroblasts (HGF) proliferation. Polymeric materials tested: two types of milled polymethylmethacrylate (PMMA-Ker and PMMA-Bre), three-dimensionally (3D) printed polymethylmethacrylate (PMMA-3D), polyetheretherketone (PEEK), and polyetherketoneketone (PEKK). Titanium (Ti) and zirconia oxide ceramics (ZrO-HT) were used as positive controls. A conventional surface cleaning protocol (CCP) was compared to a multi-step research cleaning method (RCP). Application of the RCP method allowed to reduce Sa values in all groups from 0.14&ndash, 0.28 &micro, m to 0.08&ndash, 0.17 &micro, m (p &lt, 0.05 in PMMA-Ker and PEEK groups). Moreover, the water contact angle increased in all groups from 74&ndash, 91&deg, to 83&ndash, 101&deg, (p &lt, 0.05 in the PEKK group), except ZrO-HT&mdash, it was reduced from 98.7 &plusmn, 4.5&deg, to 69.9 &plusmn, 6.4&deg, 0.05). CCP resulted in higher variability of HGF viability after 48 and 72 h. RCP application led to higher HGF viability in PMMA-3D and PEKK groups after 48 h, but lower for the PMMA-Ker group (p &lt, 0.05). After 72 h, no significant differences in HGF viability between both cleaning methods were observed. It can be concluded that the cleaning method of the polymeric materials affected surface roughness, contact angle, and HGF viability at 48 h.

To evaluate the root canal surfaces in teeth previously treated using RF resin by SEM.20 distal roots of mandibular molars with typical discoloration of tooth crown were used in this study: 10 brownish - red and 10 non-colored roots. The roots were removed from the crowns, splinted longitudinally and subjected to SEM in a back-scattered electron mode.In discolored root samples canal walls appeared without smear layer and varying amount of remaining debris, the observed morphology of dentine was ordinary. In the non-colored root samples the dentin profile revealed: in coronal third of the root just few open dentinal tubules were detected, while in the middle and apical thirds no open dentinal tubules were observed, dentin profile was similar to sclerotic dentin. The multiple dentinal defects were detected in all samples, however significantly more dentinal defects were found in the colored roots. The RF paste was well adhered to the root canal dentine and multiple tags of RF resin penetrating deeply into the dentinal tubules were detected.The surfaces of the root canal walls of the teeth treated using RF paste exhibits usual appearance and ordinary dentin morphology in colored roots while the dentin of non-colored samples has the profile of sclerotic dentin. Multiple dentinal defects could be determined by damaging effect of RF resin on dentin. The adaptation and adhesion of RF paste to the dentin, capability to penetrate into dentinal tubules is comparable with the modern resin based sealers.

The aim was to overview the etiology, prevalence and possible outcomes of dental trauma.An electronic search of Medline (PubMed), Cochrane, SSCI (Social Citation Index), SCI (Science Citation Index) databases from 1995 to the present, using the following search words: tooth injuries, tooth trauma, traumatized teeth, dental trauma, dentoalveolar trauma, oral trauma, epidemiology, etiology, prevalence, prevention, pulp necrosis, inflammatory resorption, ankylosis, cervical resorption, was performed.During last decade traumatic dental injuries were recognized as public dental health problem worldwide. Prevalence of traumatic dental injuries varies between countries. According to the existing data they are more prevalent in permanent than in primary dentition. All treatment procedures in case of dental trauma are directed to minimize undesired consequences despite that treatment of traumatic dental injuries in the young patient is often complicated and can continue during the rest of his/her life. The changing lifestyle and requirements of modern society lead to an emergence of new patterns of dental trauma. A regular update of knowledge in dental traumatology is required.

Laser-assisted gingivectomies are performed in proximity to teeth, existing restorations, and implants. In case of accidental exposures, a detrimental surface defect may cause failure. Surface interactions should be evaluated for safety margin determination of certain laser-material combinations. The purpose of this in vitro study was to assess the microscopic and visible effects of CO2, Nd:YAG, and 810-nm diode laser irradiations on various dental materials and tooth tissue.Study samples were fabricated (10 x 7.5 mm irradiation surface area, 1 mm thickness) from eight material groups (amalgam, base metal, gold, palladium-silver, composite, ceramic, titanium, and extracted tooth slices). Laser irradiations were performed with CO2, Nd:YAG, and 810-nm diode lasers using the manufacturer's recommended settings for gingivectomy at a 45-degree angle for 30 seconds. Irradiated surfaces were evaluated under SEM at 200x and 1,000x magnifications. Standardized photographs were obtained using a camera mount system (10x high-definition macro lens). The SEM images and photographs were correlated to determine surface interactions.Nd:YAG detrimentally affected all metallic materials and tooth structures. CO2 altered amalgam, gold, and palladium-silver slightly, whereas composite, ceramic, and tooth surfaces were detrimentally altered. The 810-nm diode altered amalgam, gold, titanium, palladium-silver, and composite but only gold and palladium-silver surfaces were barely traceable.Within the limitations of this in vitro study, surface effects were all instant; therefore, even a short accidental exposure may be destructive in some laser-material combinations. During gingivectomies, CO2 near tooth-colored restorations and Nd:YAG near metallic restorations and implants should be used carefully. The 810-nm diode was found to be safer due to its reversible alterations in only some materials. Further in vivo studies are necessary to clinically apply the outcomes of this study.

To analyze the need for referral to a specialist and to identify the reasons of referrals among Lithuanian general dental practitioners.Questionnaires were sent to all 2879 Lithuanian dental practitioners registered on the Lithuanian Dental Chamber license registry. The questionnaire was made with multiple-choice answers. Respondents were asked to choose only one category of answer that best fitted their clinical attitude. Questions included in the questionnaire concerned general and specific information regarding the need and main reasons for endodontic referral.Of the 2879 questionnaires mailed, 1532 questionnaires containing useful information were returned. The response rate was 53.2%. Of the 1532 respondents, 1431 were general dental practitioners. Majority (72.1%) of the respondents performed complicated root canal treatment by themselves. Almost half (49.6%) of them would like to refer patients to an endodontist. Two of the reasons, which restricted their decision, were the shortage of endodontists and high cost of the procedures in the specialized clinics. Approximately 19% of the respondents referred patients to an endodontist. The main reasons for referral were fractured instruments (86.6%), dental trauma (83.6%), difficulties in diagnostics (79%) followed by persistent symptoms (78.1%).The findings of the present study suggest that the need for referral of patients to an endodontist among Lithuanian dental practitioners exists. The main reasons for referrals were complications of endodontic treatment, traumatic injuries, difficulties in diagnostic procedures, and persistent symptoms.

The purpose of this study was to gather information about the various aspects, technical and biological, of endodontic treatment as performed by Lithuanian general dental practitioners and to compare their choices with established endodontic treatment standards of undergraduate education.Questionnaires were sent to all 2,850 Lithuanian dental practitioners. The structured questionnaire included inquiries about gender, duration of professional activity, working environment, details about instruments and materials.From total 1532 (53.8%) questionnaires were returned. Only responses from general dental practitioners (1431) were included. Of the respondents 66% never used a rubber dam. Most practitioners relied on conventional stainless steel instruments. The NiTi hand files were often and routinely used by 32.2% of the respondents. Sodium hypochlorite was the most popular choice as a root canal irrigant. Calcium hydroxide paste was used as an inter-appointment medicament. Cold-lateral condensation root filling method was used by 72.8% of the respondents while 15.6% used a paste for the root filling.The results of this study indicate that the recently graduated dental practitioners were following the recommended standard of endodontic treatment better than those with a longer time from the graduation. It is important to improve the quality of existing courses of continuous education in endodontology in order to ensure the necessary competency in clinical practice. The low use of a rubber dam and low adoption of new technologies in Lithuania is not acceptable and needs to be changed.

To gather information about the radiographic facilities and techniques used by Lithuanian general dentists.Questionnaires were sent to all 2879 Lithuanian dental practitioners registered on the Lithuanian Dental Chamber licence registry data list. The questionnaire was made with multiple-choice answers. Respondents were invited to choose the only one category of answer that best fitted their clinical attitude. Questions included in the present survey concerned general and specific information regarding peculiarities of radiographic imaging. Only answers of respondents who are licensed as general dentists were included in this study.From the 2850 questionnaires mailed 1532 were returned. The response rate was 53.8%. Of the total responses 1431 questionnaires were received from licensed general dentists. Of total 956 dentists practiced in urban and 576 dentists in rural areas. 61.6% of respondents had access to an intra-oral radiographic unit in their practice and 91.5% of them used dental radiography always or often as the diagnostic tool. To support the film packet in the patient's mouth alternatively film holder or patient's finger was used by 48% of respondents, while film holder was used only by 19.3% of dentists.Recently graduated dental practitioners more common used diagnostic radiography in endodontic pathology than dentists with a longer time from graduation. Film holder was not a popular device among general dental practitioners to perform periapical radioraphs. It is important to improve the existing dental curriculum to ensure the necessary competency when using dental radiography and film holders routinely in clinical practice.

The aim of this study was to determine and compare the microbial leakage of roots filled with EndoREZ sealer/EndoREZ Points and AH Plus sealer/ conventional gutta-percha points.60 single-rooted teeth were prepared using step-back technique. The smear layer was removed with 18% EDTA. Teeth were divided into two experimental groups (n=25 each group) and two controls (n=5 each group). In AH Plus group root canals were obturated with AH Plus sealer/gutta-percha and in EndoREZ group with EndoREZ sealer/EndoREZ Points. Five teeth were served as negative controls and five as positive controls. All teeth were inserted into Eppendorf plastic tubes and suspended in glass bottles containing sterile Schaedler broth. The coronal chambers were filled with the mix of human saliva and broth (ratio 3:1). The medium was changed every 7 days. Microbial growth in the broth was evaluated every day up to the end of experiment.Leakage in the root canals of the teeth from experimental groups occurred between 4 and 75 days. The mean leakage in AH Plus group was 18.86 days, while in EndoREZ group it was 28.28. No statistically significant difference in microbial leakage between two tested filling materials was found.Both types of root fillings - EndoREZ sealer/EndoREZ Points and AH Plus sealer/gutta-percha points - showed microbial leakage.

Research data regarding attitudes of general dental practitioners towards endodontic therapy is rare. The present review summarizes existing literature and analyzes human factors that could potentially influence the outcome of endodontic treatment in general dental practice. Root canal treatment usually fails when treatment falls short of acceptable standards. The results of questionnaire surveys from several countries indicate that differences between daily general practice and academic teaching exist. The results of studies indicated that majority of general practitioners disregard the most basic principles of endodontic treatment. The most striking finding is the generally negative attitude amongst general dental practitioners towards performing endodontic treatment and adoption of new technologies in a daily endodontic practice. The results confirm that root canal treatment is technically demanding and in general practice is carried out under less than optimal conditions. This review shows the importance of continuous dental education for practitioners in order to update their knowledge.

Purpose: Plasma-sprayed hydroxyapatite (HA)-coated implants show failures along the coating–substrate interface due to poor bond strength. We analyzed HA coatings obtained by pulsed laser deposition (PLD) and compared them to commercially used plasma-sprayed coatings with respect to their bond strength to titanium alloy (Ti-6Al-4V), as well as surface roughness alterations produced by each of the two deposition methods. Materials and Methods: Twelve titanium alloy disks were plasma-sprayed under commercial implant coating conditions, and 24 titanium alloy disks were coated using PLD. All coatings were characterized by the presence of the different calcium phosphate (CaP) phases. The plasma-sprayed coatings (n = 12) were predominantly HA, and the pulsed laser-deposited coatings were hydroxydyapatite (n = 12) and HA coating with a tetra calcium phosphate (TTCP) phase (n = 12). The surface roughness was analyzed before and after the coating processes to assess roughness changes to the surface by the coatings. The adhesive bond strengths of these coatings to the substrate titanium alloy was tested and compared. Scheffe's test was used to analyze the statistical significance of the data. Results: The surface roughness alteration following PLD was a decrease of 0.2 μm, whereas following plasma spraying the decrease was 1.0 μm. Bond strengths were as follows [mean (SD) in MPa]: pulsed laser-deposited HA coatings: 68.3 (17.8); pulsed laser-deposited HA with tetra-CaP: 55.2 (21.1); plasma-sprayed HA 17.0 (2.8). The multivariate Scheffe's test revealed that HA coatings obtained by PLD had significantly increased bond strengths compared with the plasma sprayed ones (p≤ 0.05). Conclusions: HA coatings obtained by PLD showed greater adherence to titanium alloy. PLD offers an alternative method to produce thinner coatings with better adherence properties, along with precise control over the deposition process.

A traditional concept is that apical periodontitis is the result of pathogenic effects of the microorganisms colonizing the root canal system and the response of the host defence system. The composition of the microflora of root canals differs in primary endodontic treatment and retreatment cases. Persistent disease in the periapical region after root canal treatment presents a more complex situation as it was thought earlier. Scientific evidence indicates that unsatisfactory outcome of cases in which treatment has followed the highest technical standards mainly is associated with microbial factors, comprising extraradicular and/or intraradicular infections.

To compare in vitro the cleanliness of root canal walls following automated or manual instrumentation.Thirty extracted human maxillary central incisors, maxillary and mandibular canines and premolars with single root canals were used in this study. The teeth were divided into two groups. In group 1 (20 teeth) automated canal preparation was performed using Anatomic Endodontic Technology (AET). In group 2 (10 teeth) manual instrumentation was performed with K-Flexofiles. Irrigation was performed using alternately 3.00% NaOCl and 18% EDTA, followed by rinsing with saline. The roots were split longitudinally into halves and the canals examined using a scanning electron microscope. The presence of debris and smear layer was recorded at coronal, middle and apical thirds of root canals using a four-step scoring scale. Mean scores for debris and smear layer were calculated and statistically analysed for significance (P0.05) between and within groups, using the Mann-Whitney-Wilcoxon and Friedman nonparametric tests.At coronal and middle thirds the root canals prepared with manual instrumentation had significantly less surface debris on the canal walls compared with canals prepared with AET (p0.05). At apical third root canals prepared with manual instrumentation had significantly more debris compared with AET group. The amount of smear layer was greater in the apical than in the coronal and middle thirds of the root and significantly less amount was in the AET group (P0.05).Complete cleanliness was not achieved by any of the techniques and instruments investigated. It may be inferred that the choice between AET and hand instrumentation should be based on factors other than the amount of root canal debridement, which does not vary high significantly according to the instruments used.