Scientific Letters

Efficiency and predictability of maxillary expansion with Invisalign® system

2024-02-27T16:00:04+00:00

The Invisalign^® system aims to ensure aesthetics and achieve positive clinical results; however, its efficacy is still debatable. Along with lower incisor intrusion and upper molar distalization, arch expansion is one of the most predictable movements that may be achieved using clear aligners. This makes the system a conceivable method for the correction of crowding and posterior dentoalveolar crossbites. The aim of this study is to analyze the effectiveness and predictability of tooth expansion in permanent dentition with Invisalign^® orthodontic aligners. A bibliographic search was carried out using the PubMed and EBSCOhost databases. Articles published between 2013 and 2023 and written in English were selected. Reporting of this review was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. After a thorough review, 12 articles were included. In terms of efficiency, most studies showed an increase in all interdental measurements, with premolars showing the greatest expansion. On the other hand, predictability was weaker, as significant differences were found between the post-treatment models and the ClinCheck^® software virtual model for some interdental measurements. We concluded that the Invisalign^® system is effective in producing expansion movement, with reasonable predictability.

Evaluation of the effect of mouthwashes on titanium alloy miniscrews: a systematic review

2024-04-26T19:36:25+01:00

Orthodontic miniscrews (MSs) are increasingly used in orthodontics, providing good treatment results, particularly Ti-6Al-4V MSs. Sometimes, after placing the MSs, orthodontists prescribe mouthwashing to avoid risk of infection, thus ensuring good stability and optimizing the final treatment result. The aim of this review is to analyze the effects of chlorhexidine (CHX) and sodium fluoride (NaF) mouthwashes on the surface of titanium alloy MSs and to analyze the cytotoxicity, corrosion and ion release caused. The search was carried out in the PubMed, ScienceDirect and Google Scholar databases for articles published between January 2011 and December 2023. For the study, ten articles were selected, based on exclusion and inclusion criteria. Numerous studies show that NaF seems to have more negative effects than CHX, in terms of the quantity of ions released and in terms of alteration of the surface layer, with greater corrosion and destruction of the surface microstructure. In conclusion, mouthwash with NaF alters the surface layer, causing corrosion and release of ions. Mouthwash with CHX gives good results because it causes minimal alteration of the surface layer of the MSs and minimal release of contained ions.

Exploring the Clinical Relevance of p31comet in Head and Neck Squamous Cell Carcinoma through UALCAN database analysis

2024-07-05T17:48:52+01:00

The p31^comet protein plays a pivotal role in regulating spindle assembly checkpoint silencing and is overexpressed in several cancers, including oral cancer. Despite this, its exact roles in tumorigenesis and its prognostic significance remain unclear. In this study, using the UALCAN cancer database, we analyzed p31^comet expression and its correlation with clinical indicators in Head and Neck Squamous Cell Carcinoma (HNSCC). Our findings revealed a significant upregulation of p31^comet in HNSCC patients. Interestingly, we observed a positive correlation between p31^comet expression and known interactors such as MAD2L1 and TRIP13, as well as regulators of p31^comet expression. Furthermore, we found that p31^comet expression was notably increased in tumor samples exhibiting alterations in the mTOR pathway and the SWI/SNF chromatin remodeling complexes. Intriguingly, HNSCC patients with high p31^comet expression showed a tendency towards better prognosis compared to those with low/medium expression levels. This tendency did not reach statistical significance, likely due to variations in patient cohort sizes within the database. In summary, our findings suggest that increased p31^comet expression could be a potential marker for tumor occurrence and metastasis in HNSCC patients, opening avenues for further research to understand its prognostic significance.

Coronal repercussions of maxillary central incisor torque with clear aligners – Invisalign system

2024-06-17T18:19:25+01:00

Recent years have witnessed a big evolution of clear aligner technology, due to the growing importance of aesthetics and comfort. An adequate coronal torque value has a significant impact on smile aesthetics and on the patient’s soft tissue profile. The aim of this systematic review is to evaluate the current knowledge about the efficacy of the maxillary central incisor coronal torque in the Invisalign^Ò system. This study protocol was submitted to the PROSPERO database. Literature research was performed in PubMed, EBSCO Essentials, and Cochrane Library, for articles published from January 2013 to June 2024, using MeSH terms. The literature search identified a total of 281 articles in databases and 3 articles using manual search. Finally, 6 retrospective studies were used for this review work. The ROBINS-I tool was used to assess the methodological quality of the studies. Most studies found significant differences between planned and achieved torque values using the Invisalign^®system. A study found that central upper incisor coronal torque was normally underexpressed when the teeth were moving labially and fully or overexpressed when moved lingually.

Three-dimensional evaluation of impacted maxillary canines and repercussions on adjacent teeth

2024-06-25T13:08:20+01:00

Maxillary canines have very important roles in aesthetics and function. They are the second most frequently impacted teeth. One of the most severe complications associated with impacted maxillary canines is root resorption of adjacent teeth. Cone-beam computed tomography (CBCT) provides three-dimensional multiplanar images and detailed information on dentofacial structures. The aim of this systematic review is to analyze impacted maxillary canines from three dimensions and analyze root resorption of the adjacent teeth caused by the impaction, based on CBCT only. The PRISMA methodology was applied, and a literature search of the last 11 years was carried out in PubMed and Scielo using the keywords “cone-beam computed tomography”, “maxilla”, “cuspid”, “root resorption”, “tooth, impacted”. This search was conducted through inclusion and exclusion criteria. The clinical relevance of this study consists of the need for adequate assessment of the location of impacted canines and degree of root resorption of adjacent teeth for surgeons and orthodontists to create an appropriate diagnosis and collaborative treatment plan. Lateral incisors were more affected by root resorption, especially when the widths of the crown, root length and volume were decreased. Female gender predominates; however, this is controversial. Some authors stated that the most common position of impacted maxillary canines is palatal. A statistically significant connection between bilaterally impacted maxillary canines and a greater number of teeth resorption was found; notwithstanding, the degree of root resorption is not consistent among authors. Their most frequent locations are palatal, mesial, and horizontal. Adjacent teeth located beyond the mesial surface, in contact with palatally impacted canines whose cusp tip is at the apical third of their roots, were likely to suffer root resorption.

Four-millimeter implants supporting unsplinted metal-ceramic screw-retained crowns in posterior jaw: a retrospective case series

2024-03-24T09:48:42+00:00

Little is known about the clinical performance of unsplinted crowns supported by 4-mm implants. The objective of this investigation was to evaluate the clinical performance of extra-short implants supporting single restorations. A retrospective cross-sectional study design was used and included patients treated with 4-mm implants between 2014 and 2017. The influence of crown-to-implant ratio (CI ratio), age, sex, bleeding on probing, type of arch, implant diameter, occlusion antagonist and functional loading time on mesial and distal marginal bone loss around the implants were analyzed using univariate and multivariate linear regression models. A total of 27 cone morse dental implants with 4 mm was evaluated after a minimum post-loading time of 12 months. One implant was lost after loading, leading to an implant survival percentage equal to 96,3%. No other failure conditions were observed. From the variables analyzed herein, only CI ratio, functional loading time and sex were significantly associated with marginal bone loss on the mesial site of implants; and only CI ratio, functional loading time and bleeding on probing were associated with marginal bone loss on the distal site of implants. The present results suggest that 4-mm implants placed in the posterior maxilla and mandible to support unsplinted metal-ceramic screw-retained crowns may be a very promising alternative in order to enable the rehabilitation of posterior edentulous patients, who are unable or unwilling to undergo bone grafting procedures with high morbidity. However, further prospective long-term studies should confirm if this is a viable treatment option.

Targeting p31comet to Enhance Cisplatin-induced Cytotoxicity in Oral Squamous Cell Carcinoma Cells

2024-03-27T16:06:48+00:00

p31^comet plays a crucial role in silencing the spindle assembly checkpoint during mitosis. This study aimed to investigate whether p31^comet knockdown could enhance cisplatin-induced cytotoxicity in oral cancer cells. We assessed p31^comet expression in oral squamous cell carcinoma (OSCC) cells and examined the impact of p31^comet knockdown, cisplatin treatment, and their combination on OSCC cell viability and colony formation ability. Our findings indicated an upregulation of p31^comet at both mRNA and protein levels in OSCC cells compared with non-cancer cells. Knockdown of p31^comet amplified the inhibitory effects of cisplatin on OSCC cell viability and colony formation, particularly in cells more resistant to cisplatin. This suggests that exploring the combination of p31^comet inhibition and cisplatin could be a potentially promising strategy to enhance sensitivity of oral cancer cells to cisplatin.

The Use of Artificial Intelligence to Create a Virtual Patient for Oral and Maxillofacial Surgical Planning

2024-04-08T19:13:29+01:00

The advancement of digital image acquisition technologies in dentistry has facilitated the creation of virtual patients through the integration of two- and three-dimensional (2D and 3D) images within digital platforms. These images, sourced from technologies such as Cone Beam Computed Tomography (CBCT), intraoral scanners (IOS), and 3D facial scanners, can be aligned and merged to comprehensively assess the bone structure, gingival and soft tissues, and the dentition. Additionally, 2D clinical photographs are incorporated into the digital project, enhancing aesthetic analysis and planning. Artificial intelligence (AI) algorithms can also be used to enhance and facilitate 3D image alignment. However, detailed information on digital workflows to work with virtual patients for dental and maxillofacial treatment planning is lacking in the literature. The purpose of this article is to describe a technique to create a virtual patient to assess the relationship between the patient’s soft and hard tissues with the optional use of AI to enhance the quality of 3D-reconstructed models from CBCT. Within the limitations of this study, the technique described herein is suggested to be useful for prosthetically-driven treatment planning of surgical procedures such as crown lengthening, bone grafts and dental implant placement.

Evaluation of the themes chosen for the dissertation of the Integrated Master’s Degree of the Children’s Oral Health and Prevention Service, at IUCS-CESPU

2024-07-08T10:00:41+01:00

The Children’s Oral Health and Prevention Service at IUCS-CESPU comprises three areas – Pediatric Dentistry, Orthodontics and Preventive Dentistry –, which, in the final years of the Integrated Master’s Degree in Dental Medicine, are taught within the scope of a single subject, the Pediatric Dentistry Clinic. Many of the topics covered here have stagnated due to a lack of knowledge, making it essential to recognize which areas are less popular, to captivate the interest of the students and fill these gaps. This study aimed to assess which topics in this service have more interest from dental students for their dissertations over the past eleven years. To do this, we collected all the dissertations between 2013-2023 in the Scientific Repository from the abovementioned service. Our study revealed a dominance of Orthodontics, followed by Preventive Dentistry and Psychology and Behavior Control. On the other hand, Pulpar Therapy, Diagnosis and Growth and Development are areas of little focus to students. We concluded that Orthodontics has always been the area of choice, while Preventive Dentistry, ranking second, has been in constant decline since 2015, as have Cariology and Conservative Treatments. Evaluating these choices allows us to better target teaching and meet the needs of the population.

Prevalence and characteristics of emotional distress and neurocognitive impairment in people living with HIV assisted at the Elavoco Center in Huambo/Angola

2024-06-21T16:26:39+01:00

As life expectancy among people living with HIV (PLWH) increases, there is a growing recognition of the importance of a psychological and neurocognitive well-being. This study aims to ascertain the prevalence of emotional distress and neurocognitive impairment in PLWH receiving care at the Elavoco Center. 204 participants were assessed with the Hospital Anxiety and Depression Scale and the Mini-Mental State Examination. Results indicate that 62.7% of the participants exhibit significant levels of emotional distress, with 62.7% and 53.2% experiencing significant levels of anxiety and depression, respectively. Furthermore, 58.3% demonstrate impairment in global neurocognitive functioning. Participants reporting emotional distress have lower levels of education and monthly income. Gender, limited daily access to food and potable water are associated with an increased risk of distress. Participants displaying neurocognitive impairments are older, have fewer years of formal education, exhibit depressive symptoms, and have longer periods of infection. Results are indicative of a high prevalence of emotional distress among PLWH and highlight the significance of factors such as education, income, and access to necessities like food and clean water. Consequently, the development and implementation of mental health and social services to address these critical concerns are imperative.

Evaluation of the Pediatric Dentistry themes most chosen by students for poster and oral communication presentations at the CESPU Scientific Conferences – a serial cross-sectional study

2024-06-25T10:33:33+01:00

The CESPU Scientific Conferences of Dental Sciences are organized every year and are notable for the presentation of scientific papers prepared by the students. The main aim of this study was to assess which themes, in the Children’s Oral Health and Prevention Service (SOIP), are of most interest to students for the presentation of posters and oral communications. For the analysis, we collected all the papers from the service that were presented at the Scientific Conferences between 2013 and 2023. Subsequently, the changes that occurred over the years were assessed through statistical analysis using SPSS Statistics for Windows, version 29.0. After the evaluation, it was concluded that Orthodontics is the theme most chosen by the students, followed by Systemic Diseases and Specific Needs. In turn, Sports Dentistry came in last place, having never been selected for any work. As for the Major Groups, the focus was on Craniofacial Development and Orthodontics, followed by Oral Medicine.

Anti-Spike IgG against COVID-19 three months after the end of the pandemic in Northeast of Portugal

2024-09-24T19:33:12+01:00

The emergence of new COVID-19 strains and variants and immune escape from vaccines forces reflection on the need to continue vaccinating the entire population. This study intends to monitor and understand the reinfection in recently vaccinated people. The amount of anti-Spike IgG, the number of vaccine doses, and infections/reinfections in 82 volunteers, three months after the declaration of the end of the COVID-19 pandemic, was evaluated. All participants, asymptomatic at the time, presented IgG, including those who had no infection or vaccination (n = 3). Those vaccinated showed high levels of antibodies, even 36 months after the last booster. There was no significant difference in the immunological status with the type of vaccine, age, and sex, although women and older people had higher median IgG values. A significant positive correlation was observed between vaccine doses and IgG (rs = 0.373; p < 0.001). Women vaccinated before coming into contact with the virus showed higher antibody levels (16607 vs. 6233; p = 0.012). This study suggests women’s immune systems are more effective at fighting the virus. It also supports the effectiveness of vaccines on the humoral response. However, the timing of infections is inconsistent with the expected immunity. Therefore, continuation of booster doses is questionable except for immunocompromised patients.

Editorial Acknowledgment to Reviewers of Scientific Letters in 2023

2024-01-05T11:14:36+00:00

Our commitment to prioritizing quality over quantity in the papers published in Scientific Letters remains steadfast. The overall quality of the journal is greatly indebted to the dedicated work of the Reviewers listed below. These Reviewers are chosen based on their expertise and, throughout 2023, we have been impressed by the consistently high quality of their evaluations. Reviewers selflessly invest their time to assist Authors in refining their manuscripts. It is noteworthy that a significant portion of the Reviews were submitted within the designated two-week timeframe. On behalf of the Editorial Team, I express my sincere appreciation for their exceptional contributions and eagerly anticipate continued collaboration in 2024!

Baltazar, Fátima

Bousbaa, Hassan

Caldas, Inês

Cunha, Andrea

De Marco, Paolo

Kim, Jun Ho

Pérez-Mongiovi, Daniel

Queirós, Odília

Raemdonck, Kristof

Resende, Albina Dolores

Ricardo, Sara

Schmitt, Fernando

The Brightness of Multidisciplinary Approaches in Health Sciences Research

2024-01-06T18:34:34+00:00

On behalf of the Editorial Team of Scientific Letters journal, we are pleased to announce the publication of the second issue. The second issue comprises four scientific papers, encompassing two reviews and two research articles. In 2023, Scientific Letters also published two special issues in the form of Books of Abstracts. These publications compile all abstracts that were accepted for presentation at the II TOXRUN International Congress and the II UNIPRO International Congress, both held in Portugal. We intend to add “Clinical Case Studies” and “Commentaries” to the list of article types that the journal publishes. We hope you enjoy reading this second issue and find these articles useful for your research. We invite you to submit your best papers for publication.