Forma del arco dentario en estudiantes de Medicina / Shape of the dental arch in medicine students

Introducción: Por varios siglos ha sido estudiada la forma y el tamaño de la arcada dental del ser humano. Los huesos de la mandíbula y el maxilar, la posición de los dientes, la musculatura perioral y las fuerzas funcionales intraorales determinan la forma del arco dental. Objetivo: Describir la forma de los arcos dentarios de los estudiantes de la carrera de Medicina de la Universidad Nacional de Chimborazo, durante el periodo abril-agosto de 2019. Métodos: Estudio descriptivo, transversal y cuantitativo. La muestra quedó conformada por 60 estudiantes de ambos sexos. Se realizó, en alginato y vaciados en yeso extraduro, la toma de impresiones del maxilar y la mandíbula, para identificar el tipo de arco dentario según la tabla determinada por Chuck. Resultados: En el maxilar predominó la forma cuadrara (48,30 por ciento); seguida de la ovoide (38,30 por ciento) y, por último, la estrecha (13,30 por ciento). En la mandíbula la forma predominante fue la estrecha (36,70 por ciento). Conclusiones: La mayoría de los arcos dentarios en el maxilar fueron de forma cuadrada, mientras que en el arco mandibular fueron de forma estrecha(AU)

Introduction: In humans, the shape and size of the dental arc has been studied for several centuries. The bones of the jaw and maxilla, the position of the teeth, the perioral musculature and the intraoral functional forces determine the shape of the dental arch. Objective: To determine the shape of the dental arcs in students of the School of Medicine of Universidad Nacional de Chimborazo during the period April-August 2019. Methods: A descriptive, cross-sectional and quantitative study is presented; with a universe of 320 students and the sample was formed by 60 of both sexes (female and male), who signed the informed consent. Maxillary and jaw impressions were taken using alginate and made with extra hard Dental Stone in order to identify the type of dental arc according to the table determined by Chuck. Results: In the maxilla, the square shape was observed in 48.30 percent; continue the ovoid with 38.30 percent and narrow with 13.30 percent. In the jaw the narrow shape (36.70 percent), the ovoid (35.00 percent) and the square (28.30 percent). Conclusions: Most of the dental arcs in the maxilla are square; as well as in the mandibular arc the narrow shape. In both cases, the ovoid form continued(AU)

Innovation by Computer-Aided Design/Computer-Aided Manufacturing Technology: A Look at Infection Prevention in Dental Settings.

Recent data indicates limited awareness and compliance on infection prevention procedures by dental offices and by dental laboratories. Guidelines for infection prevention in dentistry have been published by Centres for Disease Control and Prevention since 2003; the section "IX-Special consideration" includes a subsection concerning the prevention in dental laboratories, but it has not been modernised in later versions to fit the needs of traditional and computer-aided technology. Traditional techniques required disinfecting items (impression, chewing waxes, and appliances) with well-suited products, which are also chosen for limiting impression changes or appliance deterioration. Effective procedures are available with difficulties. Some of these contain irritant or non-eco-friendly disinfectants. The transport of impression, to dental laboratories, is often delayed with limited precautions for limiting cross-infection. Gypsum casts are frequently contaminated mainly by bacteria and their antibiotic-resistant strains and even stored for long periods during dental implant supported restoration and orthodontic therapy, becoming a hidden source of infection. Nowadays, computer-aided design/computer-aided manufacturing technology seems to be an interesting way to promote both business and safety, being more comfortable for patients and more accurate than traditional technology. A further advantage is easier infection prevention since, for the most part, mainly digital impression and casts are not a source of cross-infection and the transport of contaminated items is reduced and limited to try-in stages. Nevertheless, a peculiar feature is that a digital electronic file is of course unalterable, but may be ruined by a computer virus. Additionally, the reconditioning of scanner tips is determinant for the optical characteristics and long term use of the scanner, but information for its reconditioning from producers is often limited. This study focuses on some critical points including (a) insufficient guidelines, (b) choice of proper procedure for scanner reconditioning, and (c) data protection in relation to patient privacy.

Evaluation of the Efficacy of Different Mixing Techniques and Disinfection on Microbial Colonization of Polyether Impression Materials: A Comparative Study.

AIM: This study aims to determine the role of mixing techniques of polyether impression materials and efficacy of disinfection on microbial colonization of these impression materials. MATERIALS AND METHODS: Polyether impression material was mixed using two methods: First by hand mixing (group I) and second using an automixer (group II) with a total of 100 samples. Four microbial strains were studied, which included Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Candida albicans. After incubation, the bacterial colonies were counted, and then, disinfectant solution was applied. The effect of disinfection solution was evaluated for each specimen. RESULTS: The surface of polyether impression materials mixed with an automixer has less number of voids and overall a smoother surface as compared with the hand-mixed ones. On comparing the disinfection procedures, i.e., specimens without any disinfection and specimens after disinfection, statistically highly significant difference was seen between all the groups. CONCLUSION: We can conclude that impression mixing procedures are important in determining the surface characteristics of the impression and ultimately the colonization of bacteria and also determine the importance of disinfection on microbial colonization. CLINICAL SIGNIFICANCE: This study emphasises the deleterious role of nosocomial infections and specific measures that should be taken regarding the prevention of such diseases. Dental impressions are proved to be a source of such infections and may lead to transmission of such diseases. Thus, proper measures should be taken right from the first step of impression taking to minimizing and preventing such kind of contaminations in clinical practice.

Lingual mandibular osteonecrosis after dental impressions for orthodontic study models.

A 43-year-old man sought orthodontic treatment to close anterior diastemas. During the impression procedure for routine documentation, the orthodontic assistant exerted excessive pressure on the metallic tray; 2 days later, the patient reported the detachment of a small piece of mucosa overlying the mylohyoid crest and was referred to a maxillofacial surgeon with a diagnosis of lingual mandibular osteonecrosis. The etiology of bony osteonecrosis is discussed, together with the anatomic variations that can be present in the basal bone and that must be carefully checked before an impression is taken.

Comparison of Adaptation between the Major Connectors Fabricated from Intraoral Digital Impressions and Extraoral Digital Impressions.

The objective was to compare the adaptation between the major connectors of removable partial dentures derived from intraoral digital impressions and extraoral digital impressions. Twenty-four volunteers were enrolled. Each volunteer received an intraoral digital impression and one extraoral digital impression digitized from conventional gypsum impression. A software was used to create the major connectors on digital impression datasets. After all the virtual major connectors designed from Group intraoral digital impressions (Group I) and Group extraoral digital impressions (Group E) were directly fabricated by 3D printing technique, the adaptation of the final major connectors in volunteers' mouths were measured. The adaptation ranged from 159.87 to 577.99 µm in Group I while from 120.83 to 536.17 µm in Group E. The adaptation of major connectors in Group I were found better at the midline palatine suture while the adaptation of major connectors in Group E were found better at the two sides of the palatal vault. In both groups, the highest accuracy in adaptation was revealed at the anterior margin of the major connectors. It is feasible to manufacture the major connectors by digital impression and 3D printing technique. Both the adaptation of the two kinds of digital impressions were clinical acceptable.

Effect of Low-level LASER Therapy on P6 Acupoint to Control Gag Reflex in Children: A Clinical Trial.

OBJECTIVE: To investigate the effect of low level laser therapy (LLLT) on PC6 acupuncture point in suppressing gag reflex, regulating pulse rates and oxygen saturation, thereby reducing the anxiety levels. MATERIALS AND METHOD: A total of 40 patients who demonstrated hyperactive gag reflex in the age group of 4-14 years were included in the study. In Group A (20 patients), maxillary impression was recorded. In the second step, PC6 acupuncture point was stimulated with LLLT followed by recording of second maxillary impression. In group B (20 patients), steps were reversed. Gag reflex, anxiety levels, pulse rate and oxygen saturation levels were assessed. RESULTS: Values of pulse rate and oxygen saturation were regulated to normal, signifying lowered anxiety levels. Gag reflex was also significantly decreased after stimulating PC6 acupuncture point with LLLT. CONCLUSION: LLLT on PC6 point was found to be effective in lowering anxiety levels as observed by faces modified anxiety rating scale. Further, it was authenticated as the pulse rates were significantly reduced and oxygen saturation levels were significantly increased. Also, gag reflex was significantly controlled when LASER stimulation was done at PC6.

Fabrication of a Denture without Try-In Clinical Trouble Shooting.

An immediate denture is a prosthesis which is fabricated without a denture try-in procedure in the patient's mouth and inserted at the same visit immediately after extraction of the teeth. This article presents an atypical case where the immediate interim denture had to be fabricated while the patient waited in the chair.

Effect of imaging powders on the bond strength of resin cement.

The application and incomplete removal of a computer-aided design/computer-aided manufacture imaging powder may affect the dentin surface prior to bonding a ceramic restoration. The purpose of this study was to compare the effect of imaging powder residue on the shear bond strength of a self-adhesive resin cement to dentin. Mounted human third molars were sectioned coronally with a diamond saw to expose the dentin, which was then prepared with a diamond bur mounted in a custom jig. The dentin surface was sprayed with 3 different imaging powders. The 3 powder groups were then divided into 3 subgroups based on the method of powder removal: no rinse, 1-second rinse, and 10-second rinse. A control group was created that had no application of imaging powder. A self-adhesive resin cement was bonded to the surfaces and loaded to failure in a universal testing machine after 24 hours of storage. Data was analyzed with Kruskal-Wallis and Mann-Whitney nonparametric tests. The bonding to dentin surfaces of the powder groups that were rinsed for 1 or 10 seconds were not significantly different from each other or the nonpowdered control. The type of imaging powder did not significantly affect the bond strength. The nonrinsed powdered dentin surface had a significant reduction in bond strength compared to both the control and the rinsed powdered surfaces.

Nausea control by needling at acupuncture point Neiguan (PC6) during an intraoral impression-taking procedure.

The objective of this study was to evaluate the effectiveness of acupuncture point PC6 (Neiguan) in controlling nausea during intraoral impression taking. This study was conducted in Piracicaba, São Paulo, Brazil. The sample consisted of 33 adult volunteers with nausea, who were randomly divided into control and study groups, and treated with nonpenetrating sham acupuncture and real acupuncture, respectively, at acupoint PC6. The two groups had two maxillary impressions taken, one prior to acupuncture and the other after acupuncture. The nausea assessment was made using the visual analog scale, Gagging Severity Index (GSI), and Gagging Prevention Index. Volunteers' expectation that nausea would be reduced through acupuncture was also assessed. For statistical analysis, we used the t test and the Spearman correlation (p < 0.05). When assessed by Gagging Severity Index/Gagging Prevention Index, nausea was reduced in the real acupuncture group (p < 0.01). In the visual analog scale assessment, similar reductions of nausea were noted in both groups (p > 0.05). No correlation existed between the expected and the actual reductions in nausea. Our results indicate that acupoint PC6 was effective for controlling nausea during the maxillary impression-taking procedure. Patients' expectation did not influence the results.

An earplug technique to reduce the gag reflex during dental procedures.

BACKGROUND: The gag reflex is a frequent problem occurring during dental treatment procedures, especially while making impressions of the maxillary teeth. The present study aims to evaluate the efficacy of a simple earplug as an external auditory canal stimulator to supress the profound gag reflex and as a second step, to map areas of the oropharynx suppressed by this technique. METHODS: In the first step of the study, 90 patients who had a gag reflex during the impression procedure were allocated to a study group, a sham group, and a control group for evaluating the efficacy of the earplug technique. Second, 20 new patients with a gag reflex were included in order to map the oropharnygeal areas suppressed by this technique. RESULTS: The severity of the gag reflex was reduced in the earplug group (but not in the sham or the control group). The affected area included the hard palate, uvula, and the tongue but not the posterior wall of oropharynx. CONCLUSION: An earplug technique can be a useful, practical, and effective tool to overcome the gag reflex during oral procedures, such as impression procedures of maxillary teeth.

A double-blind randomised clinical trial of two techniques for gingival displacement.

Knowledge about security and the potential damage originated by the gingival displacement techniques has not been described through randomised clinical studies. This crossover, double-blind, randomised clinical trial evaluated clinical and immunological factors related to conventional and cordless gingival displacement (GD) techniques, and patients' perceptions in 12 subjects with the employment of 2 GD techniques: conventional (gingival cord + 25% AlCl3 astringent gel) and cordless (15% AlCl3 astringent-based paste). In each subject, two anterior teeth were treated and a 10-day wash-out period separated the two treatments. Periodontal indices were evaluated before (baseline) and 1 and 10 days after GD. Interleukin 1ß, interleukin 6 and tumour necrosis factor α concentrations in gingival crevicular fluid were measured before and 1 day after GD. Subjective parameters (pain, unpleasant taste and stress) were also evaluated. Data were analysed by one-way repeated-measures analysis of variance and Tukey's test (immunological factors), the Friedman test (periodontal parameters) and Fisher's exact or chi-squared test (subjective parameters), with a significance level of 95%. Gingival bleeding index, probing depth and plaque index values did not differ significantly between groups at any timepoint. Neither technique resulted in worse periodontal indices. Both techniques yielded similar results for pain and unpleasant taste, but conventional GD was significantly more stressful than cordless GD for volunteers. Both treatments significantly increased mean concentrations of the three cytokines, with the conventional technique producing the highest cytokine levels. Cordless GD is less stressful for patients and results in lower post-treatment levels of inflammatory cytokines compared with conventional GD.

Influence of gag reflex on dental attendance, dental anxiety, self-reported temporomandibular disorders and prosthetic restorations.

To assess the influence of gag reflex severity, assessed according to the short form of the patient part of Gagging Problem Assessment Questionnaire (GPA-pa SF), on the dental attendance, dental anxiety, self-reported temporomandibular disorder (TMD) symptoms and presence of prosthetic restorations among patients requiring prosthodontic treatment in Turkey. A total of 505 patients (305 women; mean age: 46·35 years, SD: 28·2 years) undergoing dental examination were administered a questionnaire containing questions regarding their age, gender, education level, dental attendance, TMD symptoms (limitation in jaw opening, muscle pain, pain/sounds in the temporomandibular jaw), the Turkish version of the Modified Dental Anxiety Scale (MDAS) and the GPA-pa SF. Subsequently, any prosthetic restoration was recorded by a dentist. Descriptive statistics, one-way analysis of variance (anova) and the chi-square test were used for statistical analysis. Differences were found between GPA-pa SF scores 0, 1 and 2 for education level (P = 0·001), MDAS scores (P = 0·003), self-reported TMD (P = 0·000) and prosthesis wear (P = 0·000), but not for attendance patterns (P = 0·826). Patients with gag reflex had lower education levels, higher levels of dental anxiety, more self-reported TMD symptoms and fewer fixed or removable prosthetic restorations than patients without gag reflex. Gag reflex has impacts on dental anxiety, self-reported TMD and prosthetic restorations, but not on dental attendance patterns, according to the results of the GPA-pa SF.

Accidental aspiration in a patient with Parkinson's disease during implant-supported prosthesis construction: a case report.

This article reports on a case history of an elderly patient with Parkinson's disease (PD) who sought treatment at a private dental office. His chief complaint was "difficulty in eating due to an illfitting prosthesis." Laboratory tests and oral radiographs were made. The surgical placement of an implant was done and, subsequently, an implant-supported prosthesis was fitted for the patient. During the impression for the construction of the implant-supported prosthesis, the patient accidentally aspirated the implant screwdriver. The object was found in the lower right lobe of the bronchus, and its removal was necessary in a hospital using bronchoscopy under general anesthesia. Patients with PD are considered at risk of aspirating and/or ingesting dental instruments. Short treatment periods are recommended, preferably during the morning, when the medication prescribed for PD is most effective. When treating patients who have a risk for aspirating and ingesting small objects, it is important to treat them in a more vertical position, and small-sized objects should be secured with dental floss to aid retrieval.

Gagging during impression making: techniques for reduction.

UNLABELLED: In everyday dental practice one encounters patients who either believe themselves, or subsequently prove themselves, to be gaggers. Gagging is most frequently experienced during impression making, but is also reported during the taking of radiographs, in the placement of restorations in posterior teeth and, in some individuals, the insertion of a finger for examination purposes. This paper describes some techniques that can easily be mastered by clinicians that may help both operator and patient avoid this unpleasant occurrence. Techniques such as acupressure, the adaptation of trays, or even the use of alternative impression materials and breathing techniques all have their place, and clinicians may have to try several of these, perhaps in conjunction, in order to assist their patients. CLINICAL RELEVANCE: A significant number of patients attend for dental treatment that require impressions, and for those with gagging problems it can be a horrendous experience. Being able to make the procedure less of an ordeal is better for all involved.

The role of acupuncture in the treatment of orthodontic patients with a gagging reflex: a pilot study.

The aim of this study was to investigate two different acupuncture approaches in the treatment of orthodontic patients with a gagging reflex (GR). Forty-five patients (mean age 10.1 + or - 2.6 years) had an upper dental alginate impression taken prior to receiving laser stimulation. GR assessment was evaluated by using the Gagging Severity Index (GSI). Fifteen patients in Group A underwent a red-light soft magnetic field laser stimulation of conception vessel 24 (CV 24) for 1 min. Fifteen other patients in Group B undertook a combination of laser stimulation of CV 24 and acupressure pericardium 6 (PC 6). Group C, which consisted of the remaining 15 patients, formed the placebo group. After the laser stimulation and acupressure, a second impression was taken. The Gagging Prevention Index (GPI) was used to evaluate gagging reflex after the laser stimulation and acupressure. Both GSI and GPI were recorded at three stages of the dental impression taking procedure, ie with an empty impression tray, with a loaded tray and the ability to keep the impression in the mouth until set. A significant decrease in GPI values compared to GSI values, was observed at the three stages of the impression taking process and after the laser stimulation in Group A and B (p <0.05). The average improvement between the GSI and GPI scores was 58.9% before and after the laser stimulation in Group B 37.9% in Group A and 11.2% in Group C. Both acupuncture points CV 24 and PC 6 were found to be effective in controlling GR in orthodontic patients.

Dental impression material: a rare cause of small-bowel obstruction.

Small-bowel obstruction due to foreign bodies is unusual in adults. Intestinal obstruction is occasionally caused by pits, bezoars, endoscopy capsules, and gastrostomy tube buttons. We report a rare case of distal small-bowel obstruction due to dental impression material. Avoidance of this potentially life-threatening complication may be achieved by increased vigilance in accounting for all impression material when dental impression trays are removed. Early detection of swallowed dental material may afford endoscopic removal from the stomach, thus preventing intestinal obstruction.

Foreign body in the maxillary sinus: report of an unusual case.

The accidental displacement of foreign bodies into the maxillary sinus is not an unusual complication in dental clinical practice. However, dental materials, and, in particular, dental impression materials, introduced into the sinus several weeks to months after a maxillary tooth extraction or dentoalveolar surgery through either a small, long-standing oroantral fistula or an insufficiently healed extraction wound is uncommon. In the case reported, 3 months after a maxillary molar extraction, the material used for maxillary impression was pushed into the antrum through a small, almost invisible, oroantral fistula that was unseen by the specialists the patient had been visiting, worsening the patient's existing sinusitis.

A clinical study on the effects of cordless and conventional retraction techniques on the gingival and periodontal health.

AIM: To investigate the influence of two cordless techniques on the periodontium in comparison with conventional cords. MATERIAL AND METHODS: Dental students (n=60) with healthy gingival conditions were recruited - an expanding poly vinyl siloxane material (Magic Foam Cord), a paste-like material (Expasyl), and a conventional retraction cord (Ultrapak) were applied on the buccal aspects of three premolars of each subject. Probing depth, clinical attachment level, gingival index (GI), plaque index, mobility, bleeding, and sensitivity were assessed at baseline, and at 1 and 7 days after application. Data were analysed using Kruskal-Wallis and Mann-Whittney tests (alpha=0.05). RESULTS: The periodontal parameters were not statistically significant among the groups at all time intervals except for the GI, which was increased for all groups after 1 day. The highest was in Expasyl (p=0.011). After 7 days, the GI returned to a non-significant level compared with baseline except for Expasyl, which was still significant (p=0.044). Expasyl induced sensitivity in four subjects. Bleeding was only induced by Ultrapak in 28.3% and 26.7% during and after retraction, respectively. CONCLUSIONS: All techniques caused a temporary gingival inflammation; the greatest was in Expasyl, which also showed slower recovery. Cordless techniques did not induce bleeding during or after retraction.

Effect of different labio-lingual spaces in tray designs on the displacement of and pressure against a mobile tooth.

The present study aimed to examine the effect of custom tray designs on the displacement of mobile tooth and local impression pressures during the impression procedure, using partially edentulous simulation models with six anterior teeth containing a mobile tooth prepared in previous studies. The custom trays were designed by altering the thickness of the respective spaces on the labial and lingual sides of the remaining tooth arch. In previous studies, the mobile tooth was displaced in the labial direction and local impression pressures of the mobile tooth were greater against the lingual side than the labial side for all custom tray designs. Furthermore, the custom trays perforated with holes on the lingual side were effective to reduce mobile tooth displacement, labial and lingual impression pressures against the mobile tooth, and the differences between them. Therefore, the present study was performed focusing on the labial and lingual thickness of spaces in custom tray designs. It was found that mobile tooth displacement, labial and lingual impression pressures against the mobile teeth and their differences were less in trays with spaces>3.0 mm thick on both the labial and lingual sides, but markedly greater in trays with a 1.5 mm-thick space on the labial side. These results indicate that the thickness of spaces on the labial side in the tray should not be reduced to prevent mobile tooth displacement.