Can Peri-Implant Marginal Bone Loss Progression and a-MMP-8 Be Considered Indicators of the Subsequent Onset of Peri-Implantitis? A 5-Year Study.

The aim of this retrospective study was to investigate the relationship between the amount of early bone remodeling, the marginal bone loss (MBL) progression, and the peri-implant sulcular fluid concentration of active metalloproteinase-8 (a-MMP-8) and the incidence of peri-implantitis (P) over 5 years of implant function. It has been documented that dental implants with a high degree of early marginal bone loss (MBL) are likely to achieve additional increased MBL during function. Moreover, it has been speculated that early increased MBL might be a predictive factor for the subsequent onset of peri-implant inflammatory diseases. Clinical and radiographic data at implant placement (T0) and restoration delivery (TR) at 6 months (T1), 2 years (T2), and 5 years (T5) post-loading were retrospectively collected. MBL levels/rates (MBLr) and peri-implant sulcular fluid levels/rates of a-MMP-8 were assessed at TR, T1, T2, and T5. Implants were divided into two groups: group 1 with peri-implantitis (P+) and group 2 without peri-implantitis (P−). A multi-level simple binary logistic regression, using generalized estimation equations (GEEs), was implemented to assess the association between each independent variable and P+. A receiver operating characteristics (ROC) curve was used to evaluate an optimal cutoff point for T1 MBL degree and a-MMP-8 level to discriminate between P+ and P− implants. A total of 80 patients who had received 80 implants between them (39 implants with a laser-microtextured collar surface (LMS) and 41 implants with a machined collar surface (MS)) were included. Periapical radiographs and a software package were used to measure MBL rates. Peri-implant sulcular implant fluid samples were analyzed by a chairside mouth-rinse test (ImplantSafe®) in combination with a digital reader (ORALyzer®). Twenty-four implants (six with an LMS and eighteen with an MS) were classified as P+. No statistically significant association was found between the amount of early bone remodeling, MBL progression, and MBLr and the incidence of peri-implantitis. Implants with a-MMP-8 levels >15.3 ng/mL at T1 presented a significantly higher probability of P+. The amount of early marginal bone remodeling cannot be considered as an indicator of the subsequent onset of P, whereas high a-MMP-8 levels 6 months after loading could have a distinct ability to predict P.

Clinical, radiographic, and biochemical evaluation of two-piece versus one-piece single implants with a laser-microgrooved collar surface after 5 years of functional loading.

AIM: To compare the clinical and radiographic conditions and the expression of pro-inflammatory cytokines in peri-implant crevicular fluid (PICF) at two-piece/bone level (TP/BL) versus one-piece/tissue level (OP/TL) single implants with a laser-microgrooved collar after at least 5 years of loading. MATERIALS AND METHODS: In total, 20 single TP/BL implants and 20 contralateral OP/TL implants, both with a laser-microgrooved collar surface, in 20 systemically and periodontally healthy subjects (12 males and 8 females, between the age of 36 and 64 [mean age of 49.7 ± 12.3 years]), were examined. Levels of IL-1ß, IL-1RA, IL-6, IL-8, IL-17, b-FGF, G-CSF, GM-CSF, IFN, MIP-1ß, TNF-α, and VEGF were assessed in PICF using the Bio-Plex 200 Suspension Array System. Plaque index (PI), probing depth (PD), bleeding on probing (BOP), and gingival recession (REC) were recorded. Radiographic crestal bone levels (CBL) were assessed at the mesial and distal aspects of the implant sites. RESULTS: The mean PI, PD, BOP, and REC values had no significant differences in either group. A higher mean value of CBL with statistical difference was detected for TP/BL compared with OP/TL implants. The levels of IL-1ß, IL-6, IL-8, GM-CSF, and MIP-1ß and TNF-α were higher at TP/BL implants than at OP/TL implants. However, only IL-1ß, IL-6, and TNF-α values presented significant differences between the groups. CONCLUSIONS: Although after 5 years of loading single TP/BL and OP/TL implants with a laser-microgrooved collar surface presented similar good clinical conditions, a higher proinflammatory state and higher crestal bone loss were detected for TP/BL implants.

Surgical-anatomical evaluation of mandibular premolars by CBCT among the Italian population.

BACKGROUND: The thorough knowledge of the anatomy of mandibular premolars is an essential factor for a correct approach to endodontic treatment, concerning both non-surgical and surgical treatment. OBJECTIVES: Since there is no data on the Italian population in this context, the aim of this study was to evaluate, from a surgical perspective, the anatomy of mandibular premolars among the Italian population through a cone-beam computed tomography (CBCT) analysis, considering the morphology of their root canals according to Vertucci's classification and the prospect of their apices with regard to the vestibular bone plate and the proximity to the inferior alveolar nerve and the mental foramen as well as to evaluate the most appropriate distance from the apex in the radicular resection (3 mm or 5 mm). MATERIAL AND METHODS: At total of 492 CBCT acquisitions (from 246 males and 246 females) were included retrospectively, evaluating 720 mandibular premolars. Age, gender, the tooth position in relation to the vestibular plate, the number of roots, the tooth length and the root length, the number of canals, the configuration of the root canal system according to Vertucci's criteria, C-shaped canals, the distance from the cementoenamel junction (CEJ) to the canal bifurcation, the number of apical foramina, and the distance from the apex to the inferior alveolar nerve or the mental foramen were evaluated. RESULTS: The study highlighted the frequent anatomic variability of the root canal system. It found the presence of 1 root for first and second premolars in 97% and 99% of cases, of 2 roots in 2.7% and 0.7% of cases, and of 3 roots in 0.3% and 0.3% cases, respectively. In 92% of cases, the mental foramen was located below a second premolar, or between a first premolar and a second premolar; only in 8% of cases, it was located close to a first premolar, but never as close as to a second premolar. CONCLUSIONS: Mandibular premolars show a truly surprising anatomical variability, especially for mandibular first premolars, which therefore requires adequate radiographic planning before providing any endodontic treatment, or especially endodontic retreatment or endodontic surgery. Taking into account proximity to the inferior alveolar nerve and the mental foramen, any surgical approach must be carefully planned. Frequently, a two-dimensional (2D) radiographic examination is not sufficient to fully understand the anatomical variability of these teeth.

In Vitro Direct and Indirect Cytotoxicity Comparative Analysis of One Pre-Hydrated versus One Dried Acellular Porcine Dermal Matrix.

Aim: The aim of the present study was to compare the direct and indirect cytotoxicity of a porcine dried acellular dermal matrix (PDADM) versus a porcine hydrated acellular dermal matrix (PHADM) in vitro. Both are used for periodontal and peri-implant soft tissue regeneration. Materials and methods: Two standard direct cytotoxicity tests­namely, the Trypan exclusion method (TEM) and the reagent WST-1 test (4-3-[4-iodophenyl]-2-[4-nitrophenyl]-2H-[5-tetrazolio]-1,3-benzol-desulphonated)­were performed using human primary mesenchymal stem cells (HPMSCs) seeded directly onto a PDADM and PHADM after seven days. Two standard indirect cytotoxicity tests­namely, lactate dehydrogenase (LTT) and MTT (3-[4,5-dimethyl-2-thiazolyl]-2,5-diphenyl-2H-tetrazoliumbromide)­were performed using HPMSCs cultivated in eluates from the matrices incubated for 0.16 h (10 min), 1 h, and 24 h in a serum-free cell culture medium. Results: The WST and the TEM tests revealed significantly lower direct cytotoxicity values of HPMSCs on the PHADM compared with the PDADM. The indirect cytotoxicity levels were low for both the PHADM and PDADM, peaking in short-term eluates and decreasing with longer incubation times. However, they were lower for the PHADM with a statistically significant difference (p < 0.005). Conclusions: The results of the current study demonstrated a different biologic behavior between the PHADM and the PDADM, with the hydrated form showing a lower direct and indirect cytotoxicity.

Metallurgical Tests in Endodontics: A Narrative Review.

Since there are no reviews of the literature on this theme, the aim of this narrative review is to summarize the metallurgical tests used in endodontics, pointing out their functional use and their pros and cons and giving readers a user-friendly guide to serve as an orientation aid in the plethora of metallurgical tests. With this purpose, a literature search for articles published between January 2001 and December 2021 was conducted, using the electronic database PubMed to collect all published articles regarding the metallurgical tests used in endodontics for the evaluation of NiTi rotary instruments. The search was conducted using the following keywords: "metallurgy", "differential scanning calorimetry" (DSC), "X-ray diffraction" (XRD), "atomic force microscopy" (AFM), "energy-dispersive X-ray spectroscopy" (EDS), "focused ion beam analysis" (FIB) and "Auger electron spectroscopy" (AES) combined with the term "endodontics" or "NiTi rotary instruments". Considering the inclusion and exclusion criteria, of the 248 articles found, only 81 were included in the narrative review. According to the results, more than 50% of the selected articles were published in one of the two most relevant journals in endodontics: International Endodontic Journal (22.2%) and Journal of Endodontics (29.6%). The most popular metallurgical test was DSC, with 43 related articles, followed by EDS (33 articles), AFM (22 articles) and XRD (21 articles). Few studies were conducted using other tests such as FIB (2 articles), micro-Raman spectroscopy (4 articles), metallographic analysis (7 articles) and Auger electron spectroscopy (2 articles).

Sulcus fluid volume, IL-6, and Il-1b concentrations in periodontal and peri-implant tissues comparing machined and laser-microtextured collar/abutment surfaces during 12 weeks of healing: A split-mouth RCT.

OBJECTIVES: To compare gingival tissue healing at surgically manipulated periodontal sites and at sites receiving implants and healing abutments with machined (MS) vs laser-microtextured (LMS) surface placed with one-stage protocol. MATERIAL AND METHODS: Twenty-four non-smoking patients each received two implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one implant with a MS collar and one immediate healing abutment with a MS, and one implant with a LMS collar and one immediate healing abutment with a LMS were used. Soft tissues healing at surgically manipulated periodontal tissues (T+) and at non-surgically manipulated periodontal tissues (T-) at MS implant sites and at LMS implant sites were compared by means of clinical and biochemical parameters at baseline and at 1-2-3-4-6-8 and 12 weeks. RESULTS: PD and BoP mean values were statistically higher in MS than LMS implant sites (p<0.05). During early healing phase (1-4 weeks), MS and LMS peri-implant tissues and periodontal tissues at T(+) showed no statistically significant difference in crevicular fluid volume changes (p>0.05). Between 6 and 12 weeks, compared with T(+), no statistically significant difference in crevicular fluid volume and IL-6 and IL-1ß concentrations was noted in LMS implant sites (p>0.05), while statistically significantly higher mean values were noted in MS implant sites (p<0.05). CONCLUSIONS: Compared with T(+) and T(-), both MS and LMS implant sites presented a higher pro-inflammatory state in the early phase after surgery (1-4 weeks). At 12 weeks, only MS implant sites kept a higher pro-inflammatory state, while at LMS implant sites, it becomes similar to T(+) and T(-).

Ultrasound Imaging in Dentistry: A Literature Overview.

(1) Background: the frequency with which diagnostic tests are prescribed with exposure to ionizing radiation, a cause of biological damage, has been studied, and with much more attention, patients are subjected to these diagnostic tests for diagnosis and follow-up. This review aimed, given the recent developments of this technology, to evaluate the possible use of ultrasound in different branches of dentistry. The possibility of applying ionizing-radiation-free diagnostic exams in dentistry, overcoming the limits of this application, has led scientific research in this area to obtain interesting results that bode well for the future. (2) Methods: a search for articles on the application of ultrasounds in dentistry was performed using the PubMed electronic database. (3) Results: only 32 studies were included, and these clearly stated that this examination is widely usable and in great progress. (4) Conclusions: regarding the modern application techniques of this diagnostic test, it is essential to consider technological evolution as an objective to reduce the damage and side effects of necessary diagnostic tests. The use of ultrasound in dentistry can represent a valid radiation-free alternative, in certain contexts, to the other most used exams.

Operative Torque Analysis to Evaluate Cutting Efficiency of Two Nickel-Titanium Rotary Instruments for Glide Path: An In Vitro Comparison.

AIM AND OBJECTIVE: The aim and objective of this study was to evaluate and compare the cutting efficacy of two different nickel titanium rotary instruments by a novel methodology: the operative torque (torque and time needed to progress toward the apex). MATERIALS AND METHODS: Ten fresh extracted upper first premolars with two canals were instrumented with a KaVo (Biberach, Germany) and a KaVo 1:1 handpiece at 300 rpm with maximum torque set at 2 N. One canal was instrumented with ProGlider NiTi rotary instruments (Dentsply Sirona Endodontics, Ballaigues, Switzerland), with tip size of 16.02, and the other one with EgdeGlidePath rotary instrument (EdgeEndo, Albuquerque, New Mexico). Mean instrumentation time, mean torque values, and maximum torque values were evaluated for each instrument. The significance level was set at p <0.05. RESULTS: EdgeGlidePath instruments reached the working length in significantly less time with a significantly smaller amount of torque when compared to ProGlider (p >0.05). No instruments exhibited flute deformation or underwent intracanal failure. CONCLUSIONS: Operative torque is related to the capability to cut dentin and progress toward the apex: the smaller the torque values, the higher the cutting ability (and safety). Operative torque is also dependent on debris removal and irrigation techniques. Nevertheless, both operative torque and instrumentation time are clinically relevant parameters for evaluating instruments' performance (i.e., cutting ability). CLINICAL SIGNIFICANCE: Operative torque during endodontic instrumentation helps understanding the overall performance in terms of both cutting efficiency and safety.

Laser microgrooved vs. machined healing abutment disconnection/reconnection: a comparative clinical, radiographical and biochemical study with split-mouth design.

BACKGROUND: Repeated removal and replacement of healing abutments result in frequent injuries to the soft tissues. PURPOSE: The purpose of this study was to evaluate the effect of disconnection/reconnection of laser microgrooved vs. machined healing and prosthetic abutments on clinical periodontal parameters, marginal bone levels, and proinflammatory cytokine levels around dental implants. MATERIAL AND METHODS: Twenty-four patients each received 2 implants with one-stage protocol in a split-mouth design on the same jaw. In each patient, one healing and prosthetic abutments with a laser microgrooved surface (LMS group) and one healing and prosthetic abutments with machined surface (MS group) were used. Four months following implant placement (T0), the healing abutments were disconnnected and reconnected three times to carry out the impression procedures and metal framework try-in. Four weeks later (T1), definitive prosthetic abutments were installated with screw-retained crowns. Modified plaque index (mPI), modified gingival index (mGI) bleeding on probing (BOP), and probing depth (PD) were recorded at T0 and T1. At the same time points, samples for immunological analyses were taken from the sulcus around each implant. Peri-implant crevicular fluid (PICF) samples were analyzed for interleukin-1beta (IL-1ß), interleukin-6 (IL-6), and tumor necrosis factor (TNF)-α levels using the ELISA kit. RESULTS: At T0 and T1, mPI and mGI showed no statistical difference between the two groups, while higher PD and BoP values were noted for the MS group (P < 0.05). The mean PICF volume and mean concentrations of IL-1ß, IL-6, and (TNF)-α in the LMS group were statistically less than those in the MS group (P < 0.05). In addition, comparison of IL-6 and IL-1ß mean concentrations at T0 and T1 in the MS group showed a statistically significant increase (p < 0.05) over time, which was not noted for the LMS. CONCLUSION: Disconnection/reconnection of healing and prosthetic abutments with a laser-microgrooved surface resulted in less inflammatory molecular response compared with conventional machined ones. TRIAL REGISTRATION: ClinicalTrials.gov NCT04415801 , registered 03/06/2020.

Longevity of Teeth and Dental Implants in Patients Treated for Chronic Periodontitis Following Periodontal Maintenance Therapy in a Private Specialist Practice: A Retrospective Study with a 10-Year Follow-up.

The aim of the present study was to retrospectively evaluate the longevity of teeth and implants during a long-term period in a cohort of periodontally compromised patients, treated and maintained in a private specialist periodontal practice, and to analyze the associated risk factors. Fifty-eight patients (30 men, 28 women) who had received active periodontal therapy (APT) and regular periodontal maintenance (PM) ≥ 10 years were included and evaluated. The following were evaluated: (1) statistically significant differences of clinical parameters assessed at six tooth or implant sites (plaque scores, bleeding score, periodontal probing depth, bleeding on probing, and gingival recession) and radiographic parameters (mesial and distal bone crest loss) between patients with and without tooth/implant loss during PM; and (2) associations between the number of teeth and implants lost and potential risk factors. During PM, the overall average tooth loss was 0.07 teeth/patient/year (0.04 teeth/patient/year for periodontal reasons), while the overall average implant loss was 0.4 implants/patient/year. The overall implant failure was 10.08%, and the rate of implant failure due to biologic reasons was 9.8%. Incidence of implant failures in patients with vs without recurrent periodontal disease was 83.3% vs 16.7% (P < .05). Results showed that in chronic periodontitis patients, ATP followed by long-term PM is successful in keeping the majority of periodontally compromised teeth. In the same patients, a higher tendency for implant loss than tooth loss was found.

Evaluation of peri-implant tissues condition after 10-15 years of loading in treated chronic periodontitis patients attending a private practice setting: A retrospective study.

OBJECTIVES: To retrospectively evaluate the conditions of the peri-implant tissues in treated patients with chronic periodontitis (CP) and in patients without chronic periodontitis (noCP). MATERIALS AND METHODS: A chart review was used to evaluate 267 implants, 134 placed in 42 CP treated patients and 133 placed in 46 noCP patients. The primary outcome was to evaluate the condition of the peri-implant tissues (health, peri-mucositis, and peri-implantitis). The secondary outcome was to evaluate the possible association of some variables, such as, Plaque Index (PI), Bleeding Index (BI), probing pocket depth (PD), bleeding on probing (BoP), bone level (BL), loading time, type of implant placement and loading protocol, type of prosthesis, type of bone, implant manufacturer, and implant diameter and length, with the implant health condition. RESULTS: The analysis of patient files revealed that after 10-15 years of loading (mean loading time 13.4 ± 2.07 years), six noCP patients (13%) experienced implant loss with a total of nine implants (6.7%) lost. The remaining 124 implants were classified: 54 (43.5%) as healthy, 45 (36.3%) with peri-implant mucositis, and 25 (20.2%) with peri-implantitis. Twelve CP subjects (28.5%) experienced implant loss with a total of 19 implants (14.1%) lost. The remaining 115 implants were classified: 34 (29.5%) as healthy, 40 (34.7%) with peri-implant mucositis and 41 (35.6%) with peri-implantitis. Compared with noCP subjects, only treated CP subjects with recurrent periodontal disease (RPD) showed differences statistically significant (p < .05). CONCLUSIONS: After 10-15 years of loading, in CP patients treated in a private practice setting, most implants (70.1%) were classified with some type of peri-implant inflammation. In patients with RPD, a higher tendency for implant loss and peri-implant biologic complications was found.

Influence of shaft length on torsional behavior of endodontic nickel-titanium instruments.

Torsional stresses are one of the most frequent causes of intracanal separation of nickel-titanium endodontic instruments, which represents a great concern of endodontists. For this reason, torsional resistance of rotary instruments has been deeply investigated by determining all parameters that can influenced it, that can be summarized in: (1) Tooth-related factors, (2) Strategy-related factors and (3) Instrument-related factors. This study was conducted to examine the influence of shaft length on torsional resistance of a nickel-titanium rotary instrument and if it should be considered as an Instrument-related factor. With this aim, 120 Twisted Files Adaptive M-L (TFA M-L) NiTi instruments (SybronEndo, Orange, CA, USA) were divided into 6 experimental groups (n = 20), according to instruments length and size: Group 1, 20 TFA M-L1 25/08 23 mm; Group 2, 20 TFA M-L1 25/08 27 mm; Group 3, 20 TFA M-L2 35/06 23 mm; Group 4, 20 TFA M-L2 35/06 27 mm; Group 5, 20 TFA M-L3 50/04 23 mm; and Group 6, 20 TFA M-L3 50/04 27 mm. All instruments were submitted to a static torsional test, blocking each instrument at 3 mm from the tip and rotating it until its fracture. Torque to Fracture (TtF) and fragments length were registered and all data were statistically analyzed. Results showed that Groups 2, 4 and 6 had a higher TtF, respectively, than Groups 1, 3 and 5, which differ from the former just for shaft length. Group 6 showed the highest torsional resistance (1.31 ± 0.08 Ncm), whilst Group 1 the lowest (0.40 ± 0.08 Ncm). According to that, it can be stated that the longer the instrument, the higher the torsional resistance is, proving that shaft length should be considered as an important factor about torsional resistance.

An Update of Possible Radiation-free Imaging Techniques in Dentistry.

Cone-beam computed tomography (CBCT) represents today the most widespread and most used 3D examination in dentistry. It is precise because of its usefulness in orthodontics and orthognathic surgery with large field of view (FOVs); in oral surgery and implantology for the 3D evaluation of bone volumes and proximity to noble structures; and in endodontics for the understanding of the often difficult root canal system anatomy with reduced FOV and greater resolution that this imaging technique, also considering the wide diffusion and availability in dental offices, in addition to the short examination execution times, allows its wide use.1-4.

Mechanical Characteristics, Testing, and Future Perspective of Nickel-Titanium Rotary Instruments.

The main drawback of several studies is the limited analysis performed for the comparison of nickel-titanium (NiTi) rotary systems. Most often, research articles in this area are focalized on the static characteristics such as static cyclic fatigue, torsional loads, and flexibility, not considering their reciprocal interaction and all dynamic factors.1 Recent evidence in the literature defines the reciprocal interaction between these parameters as a fundamental element in the study of their mechanical characteristics.2 However, static mechanical behavior is fundamental to assess the basic performance of NiTi instruments, but its interpretation during clinical practice is pointless as it does not resemble the real clinical scenario.1,3,4 Results arising from static tests, certainly valid as a first approach to the evaluation of an instrument recently introduced on the market, and comparative evaluations, should be considered in a general and more complete view, considering their reciprocal relationships.3-6 For these reasons, different types of researches that investigate both static and dynamic performance of NiTi instruments should be strongly recommended in order to give to original research and in vitro study an actual clinical significance, certainly much more indicative in view of a subsequent clinical application of NiTi rotary instruments.7-9.

Effect of Flexural Stress on Torsional Resistance of NiTi Instruments.

INTRODUCTION: Previously published studies have deeply investigated the characteristics of flexural and torsional resistance of nickel-titanium rotary instruments, but none of them investigated the relationship between the 2 stresses. The objective of the present study was to evaluate the influence of flexural stresses over torsional resistance. METHODS: Sixty S-One 20.04 files (Fanta Dental, Shanghai, China) were used in the present study (N = 60) and divided into 3 test groups of 20 files. A customized device made of a mobile structure with a connection that holds the handpiece and the artificial canal was used for the experiment to make the measurements repeatable. The artificial canals were created with a 90° curvature, a 60° curvature, and lastly a straight canal. Each file was rotated at 300 rpm with a maximum torque value of 5.5 Ncm with the apical 2 mm firmly secured in a vise. The torque at fracture and the time to fracture were recorded by the software integrated in the handpiece and evaluated through statistical analysis. RESULTS: Statistical analysis found significant differences in the values of torque to fracture (TtF) between these 3 groups (P < .05). The 90° curved canal group showed the highest TtF value, and the 60° curved canal group showed a higher TtF value than the straight canal group. CONCLUSIONS: The results of the present study demonstrated a positive influence of flexural stresses over torque at fracture of rotary files. When nickel-titanium instruments were used in a 90° or 60° curvature, the values of torque at fracture increased compared with the same instruments that rotated in the straight canal.

Academic Dental Activities and COVID-19 Pandemic.

COVID-19 pandemic has strongly and rapidly affected routine lifestyle and consequently, dental business, practice, and education. During the pandemic period, most Governments worldwide made specific regulations or recommendations to close practices, to avoid non-urgent dental therapies and treat only dental emergencies. Some recent surveys1,2 showed how dentists perceived the COVID-19 risk and how they reacted: by modifying their way of working, by reducing aerosol producing procedures, by improving staff and patient's safety with the increased use of personal protective equipment, environmental disinfection and limited access to dental offices, increasing use of remote consulting and triage.

Fine Aerosols and Perceived Risk of COVID-19 among Italian Dental Practitioners: An Experimental Survey.

AIM: The aim of the present study was to take a survey on Italian practitioners concerning the perceived risks of aerosol contamination in COVID-19 times and their attitude toward modifications of treatment protocols to reduce this risk. MATERIALS AND METHODS: Power analysis calculated a minimum sample size of 150 participants at 99% confidence level with a 5% margin of error. To homogenize responses elicited by different preventive measures by various national governments, only Italian dentists were included in the survey: overall 500 responses were collected. RESULTS: Of the 500 analyzed respondents, there were 266 females and 234 males; 379 practitioners were allocated in the more experienced groups, and the remaining 121 in the less experienced group based on less or more than 5 years of practice. The 70% of the dentists consider the dental practice more dangerous for the diffusion of COVID-19 than other social activities. The 5% consider dental practice more dangerous only for the patients. Aerosol contamination was perceived as a risk from the most dentist (70%), but there was agreement on the most dangerous way of cross infection in dental settings. Most of the dentists (55%) believed implementations in their protocols were needed to reduce the risk of COVID-19 infections. No significant differences were found within the groups: both women and men, as well as practitioners with different experience levels (younger or older than 35 years) perceived very similarly the problems related to COVID-19 in dentistry (p > 0.05). CONCLUSION: The survey demonstrated that COVID-19 had a great impact on dental practitioners; it increased not only fear of aerosol contamination during dental treatments but also influenced the fear of close contacts. SIGNIFICANCE: Airborne and waterborne infections are related with dental treatments and considered the preferred ways of diffusion for COVID-19. The risk of aerosol-related infections could interfere with the clinical practice of the dentist, during the COVID-19 pandemic; the limitations that provided changes to everyday behavior could affect the perception of the safety of the operators, staff, and patient and this could also affect economically the dental office.

A Survey on Perceived COVID-19 Risk in Dentistry and the Possible Use of Rapid Tests.

AIM: The present study was conducted to assess the perceived risk of COVID-19 transmission in dental professionals (DPs), that include dentists and dental auxiliary staffs, and whether rapid tests should be a recommended tool to constrain the transmission of the COVID-19, and who should be bearing their cost (governments, dentists, or patients) through an online survey. MATERIALS AND METHODS: A sample size of n = 700 was recruited in the study. The study included DPs from all over the world. A randomized selection of samples was done through dental groups present on social networks. An online survey was conducted in April 2020, using the Google Form software to provide questions and collect and elaborate answers. Data were analyzed using the statistical software STATA and presented in terms of percentages. RESULTS: About 78% of the study participants perceived a very high risk of COVID-19 contamination in dental settings. Nearly 80% of the study participants were willing to be subjected to rapid tests and the same could be performed on patients visiting their dental clinics, which could prevent the spread of the disease. About 55% of the participants had reported that additional costs for the rapid tests should be borne by the governments. CONCLUSION: The results of the present survey report that DPs do not feel safe and perceive a high risk of COVID-19 contagion and prevention of the disease could be done by performing rapid tests on dentists, dental staff, and patients visiting the dental clinics irrespective of age and gender of the participants. SIGNIFICANCE: Since all the dentists and allied staff have perceived increased risk for COVID-19 transmission, it is important that preventive measures are implemented through rapid test kits at the earliest.

Fatigue Resistance of Two Nickel-Titanium Rotary Instruments before and after Ex Vivo Root Canal Treatment.

AIM: The aim of the present study is twofold: to evaluate cyclic fatigue resistance differences of two different nickel-titanium rotary instruments, brand new and after an ex vivo instrumentation of single root extracted teeth. MATERIALS AND METHODS: Twenty new S One 20.06 were randomly divided into two groups. The first group (n = 10) was immediately subjected to a cyclic fatigue test (S One Group I). The second group (n = 10) (S one Group II) performed a cyclic fatigue test after three ex vivo root canal treatment with a single-file technique. The same process has been carried out for 20 M-Two 20.06 instruments. RESULTS: Mean time to fracture (TtF) for Group I was 51.14 ± 1.28 for S One and 32.62 ± 0.17 for M-Two 20.06 and for Group II was 46.00 ± 0.99 for S One and 27.75 ± 1.58 for M-Two 20.06. The reduction in TtF values from Group I to Group II was 11% for S One and 15% for M-Two. Statistical analysis found significant differences in all the groups examined (p value < 0.05). Mean fragment length (FL) for Group I was 3.07 ± 0.17 for S One and 3.05 ± 0.14 for M-Two 20.06 and for Group II was 3.05 ± 0.07 for S One and 3.05 ± 0.14 for M-Two 20.06. Statistical analysis was pursued, and no significant difference was found (p value > 0.05). CONCLUSION: The S-One showed significantly more resistance to cyclic fatigue stress than M-Two for both new and used instruments. This validates the hypothesis that the AF H wire enables the S One files to endure more the cyclic fatigue stresses. CLINICAL SIGNIFICANCE: This study demonstrates the cyclic fatigue resistance of a new endodontic instrument after repetitive usage.

Minimally Invasive Intraoral Approach to Submandibular Lodge.

The purpose of this study is to describe the Minimally Invasive Intraoral Approach (MIIA) performed on selected cases of abscesses and neck phlegmons of odontogenic origin when the infection has not spread beyond the inferior mandibular margin. This technique allows us to avoid cervicotomy by a direct approach to the abscess, draining it through the oral cavity. If the limits have already been crossed, then cervicotomy is necessary. The aim of the study is to show the surgical outcomes that we have achieved during a time span of two years, and to show the effectiveness of the MIIA and its results. We selected 66 patients with abscesses and neck phlegmons, from January 2018 to June 2020. Among these cases, five patients were excluded as it was not possible to recover medical records from database. The MIIA technique has been performed on 16 patients (26.2%) when a successful dental extraction and drainage of the submandibular lodge were accomplished. The patients who underwent the MIIA surgery have all perfectly healed and did not suffer from relapses during the follow-up. The results show the achievement of excellent healing, underlining the lower impact required by MIIA when compared to a more traditional approach through cervicotomy.