Effect of different mechanical surface treatments on flexural strength of repaired denture base / Efecto de diferentes tratamientos superficiales mecánicos sobre la resistencia a la flexión de la base de la dentadura reparada

Aim: To assess the effect of different mechanical surface treatments on flexural strength of repaired denture base. Material and Methods: Sixty bar-shaped specimens of heat-polymerized acrylic resin were fabricated, and divided into six groups (n=10). All specimens, except the positive control group (group PC), were sectioned into halves to create a 1-mm clearance. A negative control group with no surface treatment (group NC) was also considered. Other groups underwent different surface treatments: group Laser; treated with erbium: yttrium-aluminum-garnet (Er:YAG) laser, group APA; airborne-particle abrasion (APA), group APA plus Laser; a combination of laser and APA, and group Bur; bur grinding. After measuring surface roughness (Ra) with a profilometer, all sectioned specimens were repaired by auto-polymerizing acrylic resin, and thermocycled afterward. Three-point bending test was performed by a universal testing machine. Data were statistically analyzed (α=0.05). Results: The mean surface roughness of all experimental groups were significantly higher than that of group NC (p<0.05). The mean flexural strength of all groups was significantly lower than that of group PC (p<0.05). Group B had significantly higher flexural strength than the other surface-treated groups (p<0.05). Group Laser had significantly higher flexural strength than groups APA (p=0.043) and APA plus Laser (p=0.023). No significant difference was found between groups APA and APA plus Laser (p=0.684). Conclusion: All surface treatments increased the surface roughness and flexural strength compared with the untreated group. The highest flexural strength was observed in specimens treated by bur grinding and then laser, however, it was still significantly lower than intact specimens.

Objetivo: Evaluar el efecto de diferentes tratamientos superficiales mecánicos sobre la resistencia a la flexión de la base de la prótesis reparada. Material y Métodos: Se fabricaron sesenta especímenes en forma de barra de resina acrílica termo-polimerizada y se dividieron en seis grupos (n=10). Todas las muestras, excepto el grupo de control positivo (grupo PC), se seccionaron en mitades para crear un espacio libre de 1 mm. También se consideró un grupo de control negativo sin tratamiento superficial (grupo NC). Otros grupos se sometieron a diferentes tratamientos superficiales: grupo Láser; tratados con láser de erbio: itrio-aluminio-granate (Er:YAG), grupo APA; abrasión por partículas en el aire (APA), grupo APA más láser; una combinación de láser y APA, y grupo Bur; molienda de fresas. Después de medir la rugosidad de la superficie (Ra) con un perfilómetro, todas las muestras seccionadas se repararon con resina acrílica de autopolimerización y se sometieron a termociclado. La prueba de flexión de tres puntos se realizó con una máquina de prueba universal. Los datos se analizaron estadísticamente (α=0,05). Resultados: La rugosidad superficial media de todos los grupos experimentales fue significativamente mayor que la del grupo NC (p<0,05). La resistencia media a la flexión de todos los grupos fue significativamente menor que la del grupo PC (p<0,05). El grupo B tenía una resistencia a la flexión significativamente mayor que los otros grupos tratados en la superficie (p<0,05). El grupo Láser tuvo una resistencia a la flexión significativamente mayor que los grupos APA (p=0,043) y APA más Láser (p=0,023). No se encontró diferencia significativa entre los grupos APA y APA más Láser (p=0,684). Conclusión: Todos los tratamientos superficiales aumentan la rugosidad de la superficie y la resistencia a la flexión en comparación con el grupo sin tratar. La resistencia a la flexión más alta se observó en las muestras tratadas con fresado y luego con láser; sin embargo, aún era significativamente más baja que las muestras intactas.

Alternativas clínicas para el uso de composites Bulk-Fill compactables y fluidos: Reporte de un caso paso a paso / Clinical Alternatives for the Use of Compactable and Flowable Bulk-Fill Composites: A Step-by-Step Case Report

Resumen: El uso de resinas compuestas Bulk-Fill para la restauración de dientes posteriores ha sido masificada en los últimos años en las diferentes disciplinas clínicas de la Odontología. Esto puede deberse principalmente a la simplicidad en la técnica de aplicación de este material ya que requiere de su inserción dentro de la preparación cavitaria en espesores de resina compuesta de hasta 4-5mm, lográndose una reducción considerable de tiempo de trabajo clínico. Ante la existencia de diferentes viscosidades de este tipo de resinas compuestas, ciertas dificultades han sido identificadas ante la selección de cada material Bulk-Fill en relación a las posibles combinaciones que se pueden realizar entre las diferentes marcas disponibles en el mercado, inclusive cuando se usan junto con resinas compuestas convencionales. El objetivo del siguiente reporte de caso, es mostrar dos posibilidades clínicas paso a paso utilizando inicialmente resinas Bulk-Fill compactable en un solo incremento para un segundo molar superior, y luego, a través de la combinación de resinas compuestas Bulk-Fill del tipo fluidas, junto a resinas compuestas Bulk-Fill compactables y resinas compuestas convencionales de estratificación para esmaltes de alto índice de refracción para un primer molar superior.

Abstract: The use of Bulk-Fill composite resins to perform posterior restorations has been massified in recent years in the different clinical disciplines of Dentistry. This may be due mainly to the simplicity in the application technique of this material as it requires its insertion into the cavity preparation in 4-5mm of composite resin thickness, achieving a considerable reduction of clinical working time. Given the existence of different viscosities of this type of composite resins, certain difficulties have been identified before the selection of each Bulk-Fill material related to the possible combinations that can be made between the different brands available in the market, even when they are used with conventional composite resins. The purpose of the following case report, is to present two step-by-step clinical possibilities using initially, compactable Bulk-Fill composite resin in a single increment for the restoration of a second upper molar, and later, through the combination of Bulk-Fill flowable composite resin together with compactable Bulk-Fill composite resin and a high- refractive-index enamel-like conventional composite resin, for a first upper molar.

Comparison of metal wire reinforcement and glass fiber reinforcement in repaired maxillary complete denture / 대한치과보철학회지

PURPOSE: This study compared fracture strength and fracture modes between metal wire reinforcement and glass fiber reinforcement in repaired maxillary complete denture. MATERIALS AND METHODS: In this study, fracture was reproduced on center of maxillary complete dentures and the denture was repaired with auto-polymerizing resin. The experimental groups (n = 10) were subjected to the following condition: without reinforcing material (control group), reinforcing with metal wire (W group), reinforcing with glass fiber pre-impregnated with light-curing resin (SES MESH, INNO Dental Co., Yeoncheon, Korea, G group). The fracture strength and fracture modes of a maxillary complete denture were tested using Instron test machine (Instron Co., Canton, MA, USA) at a 5.0 mm/min crosshead speed. The flexure load was applied to center of denture with a 20 mm diameter ball attachment. When fracture occurred, the fracture mode was classified based on fracture lines. The Kruskal-wallis test and the Mann-whitney U test were performed to identify statistical differences at alpha=.05. RESULTS: W group showed the highest value of fracture strength, there was no significant difference (P>.05) between control group and G group. Control group and W group showed anteroposterior fracture mainly, group W showed adhesive fracture of denture base and reinforcing material. CONCLUSION: In limitation of this study, the glass fiber did not improve the fracture strength of repaired maxillary complete denture, and adhesive failure was occurred along the lines of glass fiber.

Number of implants for mandibular implant overdentures: a systematic review

PURPOSE: The aim of this systematic review is to address treatment outcomes of Mandibular implant overdentures relative to implant survival rate, maintenance and complications, and patient satisfaction. MATERIALS AND METHODS: A systematic literature search was conducted by a PubMed search strategy and hand-searching of relevant journals from included studies. Randomized Clinical Trials (RCT) and comparative clinical trial studies on mandibular implant overdentures until August, 2010 were selected. Eleven studies from 1098 studies were finally selected and data were analyzed relative to number of implants. RESULTS: Six studies presented the data of the implant survival rate which ranged from 95% to 100% for 2 and 4 implant group and from 81.8% to 96.1% for 1 and 2 implant group. One study, which statistically compared implant survival rate showed no significant differences relative to the number of implants. The most common type of prosthetic maintenance and complications were replacement or reattaching of loose clips for 2 and 4 implant group, and denture repair due to the fracture around an implant for 1 and 2 implant groups. Most studies showed no significant differences in the rate of prosthetic maintenance and complication, and patient satisfaction regardless the number of implants. CONCLUSION: The implant survival rate of mandibular overdentures is high regardless of the number of implants. Denture maintenance is likely not inflenced substantially by the number of implants and patient satisfaction is typically high again regardless os the number of implants.

Flexural strength of acrylic resin repairs processed by different methods: water bath, microwave energy and chemical polymerization

Denture fractures are common in daily practice, causing inconvenience to the patient and to the dentists. Denture repairs should have adequate strength, dimensional stability and color match, and should be easily and quickly performed as well as relatively inexpensive. OBJECTIVE: The aim of this study was to evaluate the flexural strength of acrylic resin repairs processed by different methods: warm water-bath, microwave energy, and chemical polymerization. MATERIAL AND METHODS: Sixty rectangular specimens (31x10x2.5 mm) were made with warm water-bath acrylic resin (Lucitone 550) and grouped (15 specimens per group) according to the resin type used to make repair procedure: 1) specimens of warm water-bath resin (Lucitone 550) without repair (control group); 2) specimens of warm water-bath resin repaired with warm water-bath; 3) specimens of warm water-bath resin repaired with microwave resin (Acron MC); 4) specimens of warm water-bath resin repaired with autopolymerized acrylic resin (Simplex). Flexural strength was measured with the three-point bending in a universal testing machine (MTS 810 Material Test System) with load cell of 100 kgf under constant speed of 5 mm/min. Data were analyzed statistically by Kruskal-Wallis test (p<0.05). RESULTS: The control group showed the best result (156.04±1.82 MPa). Significant differences were found among repaired specimens and the results were decreasing as follows: group 3 (43.02±2.25 MPa), group 2 (36.21±1.20 MPa) and group 4 (6.74±0.85 MPa). CONCLUSION: All repaired specimens demonstrated lower flexural strength than the control group. Repairs with autopolymerized acrylic resin showed the lowest flexural strength.

Effect of cavity preparation on the flexural strengths of acrylic resin repairs

OBJECTIVE: To investigate the effect of cavity preparation on the flexural strength of heat-curing denture resin when repaired with an auto-curing resin. MATERIAL AND METHODS: Ninety-six rectangular specimens (64x10x2.5 mm) prepared from heat-curing denture base resin (Meliodent) were randomly divided into four groups before repair. One group was left intact as control. Each repair specimen was sectioned into two; one group was repaired using the conventional repair method (Group 1). Two groups had an additional transverse cavity (2x3.5x21.5 mm) prepared prior to the repair; one repaired with (Group 2) and one without glass-fiber reinforcement (Group 3). A three-point flexural bending test according to the ISO 1567:1999 specification8 for denture base polymers was carried out on all groups after 1, 7 and 30 days of water immersion. Statistical analysis was carried out using two-way ANOVA, Kruskal Wallis and post-hoc Mann Whitney tests. RESULTS: The highest flexural strength was observed in the control group. Control and conventional repairs group (Group 1) showed reduction in the flexural strength 30 days after water immersion. No significant change in the strength was observed for Groups 2 and 3 where the repair joints were similarly prepared with additional transverse cavity. CONCLUSION: Repaired specimens showed lower flexural strength values than intact heat-curing resin. Cavity preparation had no significant effect on the flexural strength of repair with water immersion.

The effect of chemical and mechanical treatment of the denture base resin surface on the shear bond strenght of denture / Efeito do tratamento químico e mecânico da superfície da resina de bases de dentaduras nas forças de cisalhamento em reparos de dentaduras

OBJECTIVE: This study was aimed to evaluate the effect of three surface treatment methods on the shearbond strength of denture repairs. MATERIAL AND METHOD: 40 specimens (15 x 15 x 7mm) were fabricated according to the manufacturers’ instructions from each of three denture base materials: a heat-cured acrylic resin (VeracrilTM), a rapid-setting heat-cured acrylic resin (QC-20TM), and a pourable resin (Selecta PlusTM). The samples of each material were divided into four groups of ten. One of the groups served as a control and underwent no surface treatment. The other groups received one of three surface treatments: air blasting with 50 ìm aluminum oxide particles at 0.5 MPa pressure for 5 seconds; immersion in methyl methacrylate (MMA) for 180 seconds or immersion in acetone for 3 seconds. An autopolymerizing repair resin (Rapid RepairTM) was applied to the bonding area (6 mm in diameter, 2 mm in height) and polymerized at a pressure of two bar for 30 minutes using a pressure pot. All specimens were subjected to 10,000 thermal cycles. The shear bond strength (MPa) of the specimens was measured in a universal testing machine at a 1 mm/min crosshead speed. The effect of the mechanical and chemical treatments on the surface of the base resins wasexamined using SEM. Statistical tests used were 2 way ANOVA and Kolmogorov-Smirnov. The level ofstatistical significance was established at (p<0.05). RESULTS: There were statistically significant differencesbetween bond strength in surface treatment levels across acryl level categories (p=0.042). The results also showed differences between treatment levels (p=0.0001).Abrasive blasting significantly increased the bond strength of the repair material, but there were no significant differences between the bond strengths of the control group and the experimental groups treated with MMA or acetone. Examination by SEM revealed that chemical treatment with MMA or acetone produced a smooth surface similar...

OBJETIVO: O presente estudo foi dirigido para avaliação do efeito de três métodos de tratamento de superfície na reparação de resinas-base de dentaduras. MATERIAL E MÉTODO: 40 espécimes (15 x 15 x 7 mm) foram fabricados de acordo com as instruçõesdos fabricantes de cada um de três materiais-base de dentaduras: uma resina termopolimerizada (VeracrilTM); uma resina de termopolimerização rápida (QC-20TM) e uma resina autopolimerizável (Selecta PlusTM). Cada material foi dividido em quatro grupos de dez corpos de prova. Um dos grupos serviu como controle, não recebendo tratamento de superfície. Os outros grupos receberam três tipos de tratamento de superfície: jato abrasivocom partículas de óxido alumínio (50) com pressão de 0,5 MPa durante cinco segundos; imersão em metil metacrilato (MMA) por 180 s; imersão em acetona por três segundos. Uma resina de reparo autopolimerizável (Rapid Repair TM) foi aplicada na área de adesão (6 x 2 mm) e polimerizada sob pressão de duas atmosferas por 30 minutos, utilizando um frasco de pressão. Todos os espécimes foram sujeitos a 10.000 ciclos térmicos. A resistência às forças de cisalhamento foi medida numa máquina universal de testes a uma velocidade de 1 mm/min. O efeito do tratamento químico e mecânico das superfícies da resina base foi avaliado usando SEM. Testes estatísticos utilizados foram ANOVA e Kolmogorov-Smirnov. O nível de significância estatística foi estabelecido a p<0.05. RESULTADOS: Houve diferenças estatisticamente significantes na resistência ao cisalhamento entre as categorias de tratamento de superfície (p=0,042). Os resultados também mostraram diferenças entreníveis de tratamento (p=0,0001). O jato abrasivo aumentou significativamente a resistênciaao cisalhamento do material de reparo, mas não houve diferenças significativas entre a resistência do grupo controle e dos grupos experimentais tratados com MMA ou acetona. O exame com microscopia eletrônica demonstrou que o tratamento químico com MMA...

Ceramic restoration repair: report of two cases

The esthetic and functional rehabilitation of patients with multiple missing teeth can be performed with several techniques and materials. Ceramic restorations provide reliable masticatory function and good esthetics. However, fracture can occur in some cases due to their brittle behavior. In some cases, the replacement of an extensive prosthesis is a problem due to the high treatment cost. In this paper, two cases are presented, in which fractures occurred in extensive metal-ceramic fixed partial dentures, and their replacement was not possible. Ceramic repair was chosen and the sequences of treatment with and without presence of the ceramic fragment are also discussed. The cases illustrate that, in some situations, fractured metal-ceramic partial dentures can be successfully repaired when prosthetic replacement is not a choice. Prosthodontists must use alternatives that allow a reliable repair to extensive metal-ceramic fixed partial dentures. Surface preparation of the ceramic with hydrofluoric acid in conjunction with a silane coupling agent is essential for a predictable bonding of composite resin. The repair performed with composite resin is an esthetic and functional alternative when extensive fixed partial dentures cannot be replaced.

Effect of chemical surface treatments and repair material on transverse strength of repaired acrylic denture resin.

PURPOSE: This study was performed to evaluate the transverse strength of a denture base resin (H), repaired with an autopolymerizing acrylic resin (A) or a visible light-curing (VLC) resin (T) following the use of three chemical solvents: methyl methacrylate monomer, aceton or chloroform. MATERIALS AND METHODS: Eighty specimens (65.0 x 10.0 x 3.3 mm) of H were fabricated and stored in distilled water at 37 degrees C for seven days. Specimens were divided into eight equal groups of 10. In each group, specimens were sectioned in the middle to create a 10 mm gap. Two groups served as controls and had no surface treatment. They were repaired with A or T materials. In the remaining six experimental groups, specimen surfaces were treated with ac for 30 sec or mma for 180 sec or ch for 5 sec. Then A or T material was placed on the treated surfaces, using the same preparation molds. After seven days' storage at 37 degrees C, the transverse bond strength (MPa) of the specimens was measured using a three-point bending test. A two-way ANOVA and a Tukey HSD were performed to identify significant differences ( P < 0.05). The nature of the failures was noted as adhesive, cohesive or mixed. RESULTS: Significant differences were found between the controls and experimental groups ( P < 0.05). In the control groups, repair with A showed significantly higher strength (60.3 MPa) than those repaired with T (51.3 MPa). Mean transverse strength of experimental specimens repaired with A was (75.06 MPa) which was significantly greater than those repaired with T (67.9 MPa). Although surface treatment increased repair strength, no significant differences were detected between the effects of the chemical etchants. CONCLUSIONS: The autopolymerizing resin exhibited significantly higher repair strength than VLC resin. The transverse strength of the repaired specimens was increased significantly after chemical treatments.

A comparative study on the dislodging force of magnetic attachment to the denture resin by magnetic design and fixing materials / 대한치과보철학회지

STATEMENT OF PROBLEM: Detachment of the magnetic assembly from the denture base has been a problem in magnetic overdenture patients. PURPOSE: The objectives of this study were to compare the dislodging force by the fixing materials and the designs of the magnetic assembly, and to compare the effect between the fixing materials and the designs of the magnetic assembly. MATERIAL AND METHODS: Two fixing materials, Jet denture repair acrylic(R) and Super-Bond C&B(R) and two types of magnetic assembly designed with or without wing were used. Each magnetic assembly was fixed in the chamber of the denture base resin block (Lucitone(R)199) with each fixing material respectively. These specimens were thermocycled 2,000 cycles in the water held at 4degrees C and 60degrees C with a dwell time of 1 min each time. Each specimen was seated in a testing jig and then a push-out test was performed with a universal testing machine at a cross head speed of 0.5 mm/min to measure the maximum dislodging forces. RESULTS: Comparing the fixing materials, Super-Bond C&B(R) showed superior dislodging force than Jet denture repair acrylic(R). Comparing the design of the magnetic assemblies, the wing design magnetic assembly showed better dislodging force. Combination of the Super-Bond C&B(R) as a fixing material and wing design magnetic assembly revealed a greatest dislodging force. The kind of fixing material was more influential than the type of magnetic assembly. CONCLUSION: The dislodging force of Super-Bond C&B(R) was significantly higher than Jet denture repair acrylic(R). And the dislodging force of magnetic assembly which have wing design was significantly higher than magnetic assembly which have no wing design.

Fracture toughness of self-curing denture base resins with different polymerizing conditions / 대한치과보철학회지

PURPOSE: The intent of this study was to evaluate the effects of curing conditions on selfcuring denture base resins to find out proper condition in self-curing resin polymerization. MATERIALS AND METHODS: In this study, 3 commercial self-curing denture base resins are used: Vertex SC, Tokuso Rebase and Jet Denture Repair Acrylic. After mixing the self curing resin, it was placed in a stainless steel mold(3x6x60mm). The mold containing the resin was placed under the following conditions- in air at 23 degrees C, or in water at 23degrees C; or in water at 23degrees C under pressure(20psi); or in water at 37degrees C under pressure(20psi); or in water at 50degrees C under pressure(20psi); or in water at 65degrees C under pressure(20psi), respectively. Also heatcuring denture base resin is polymerized according to manufacturers' instructions as control. Fracture toughness was measured by a single edge notched beam(SENB) method. Notch about 3mm deep was carved at the center of the long axis of the specimen using a dental diamond disk driven by a dental micro engine. The flexural test was carried out at a crosshead speed 0.5mm/min and fracture surface were observed under measuring microscope. RESULTS AND CONCLUSION: The results obtained were summarized as follows : 1. The fracture toughness value of self-curing denture base resins were relatively lower than that of heat-curing denture base resin. 2. In Vertex SC and Jet Denture Repair Acrylic, higher fracture toughness value was observed in the curing environment with pressure but in Tokuso Rebase, low fracture toughness value was observed but there was no statistical difference. 3. Higher fracture toughness value was observed in the curing environment with water than air but there was no statistical difference. 4. Raising the temperature in water showed the increase of fracture toughness.

clinical study of complete denture fractures at four military Hospitals in Jordan

To analyze and determine the causes of complete denture fractures. Data were collected from patients who attended prosthodontic clinics for denture repairs at four military hospitals. For each patient requiring repair of a fractured complete denture, the variables were recorded: causes of denture fracture, the type of fracture and the history of pervious recurrent fractures. Of 552 repaired dentures 320 [58%] were complete dentures, 154 [28%] were removable partial dentures, which were excluded from the study, and 78 [14%] involved replacement of the teeth that had deboended from the denture bases. The ratio of upper to lower complete denture fractures was approximately 2|:1, most of the fractured dentures [63%] were those of males. Poor fit appeared to be the main cause of denture fracture 116 [36%], and poor occlusion was the second most common cause recorded 54 [17%]. Midline fracture was the most common type of fracture during the period of study 195 [61%]. Most of the fractured denturess 185 [58%] had previously been repaired once or more. The total number of complete denture fractures was considerably enhanced by repetitive fractures, which can be reduced by the application of prosthetic principles in constructing and maintaining dentures particularly during the laboratory stages. Improvements in the processing techniques and the type of resin can reduce the incidence of denture fracture. Various polymers have been developed for use as denture base resins to overcome some of the mechanical deficiencies of polymethylmethacrylate

Electroestimulación superficial como coadyuvante en la consolidación de fracturas del maxilar inferior, Hospital Regional de Apartadó (Antioquia), Noviembre 1994 – Mayo 1996 / Superficial electro stimulation as a complementary therapy in the consolidation of mandibular fractures at the Regional Hospital in Apartado, Colombia between November 1994 and May 1996

Con base en estudios sobre las relaciones entre el estrés mecánico y los potenciales eléctricos que éste genera, y en la respuesta del hueso a la corriente eléctrica, se hizo un estudio en 12 de los pacientes del Hospital Regional de Apartadó (Antioquia) que ingresaron entre noviembre de 1994 y mayo de 1996 con fracturas no complicadas del maxilar inferior. A las técnicas convencionales de intervención se adicionó la estimulación eléctrica para producir una "aceleración" biológica de la normalización del hueso afectado. -La estimulación eléctrica se aplicó durante cuatro semanas, durante un mínimo de ocho horas diarias. El proceso de reparación ósea se evaluó clínica y radiográficamente al iniciar el tratamiento, a las cuatro y a las seis semanas.- Todos los pacientes tuvieron consolidación clínica a las cuatro semanas; cinco de ellos no presentaron consolidación radiográfica. A las seis semanas todos registraron consolidación clínica y solamente cuatro no mostraron callo óseo en las radiografías.-Todos tuvieron una evolución muy favorable y se acortó el período de convalecencia de una manera significativa.

Sistema perno muñón vaciado metálico / Metalic cast dowel-core system

La presente revisión bibliográfica recopila en forma breve, los primeros intentos por devolver forma y función a piezas con su estructura coronaria comprometida. Desde Fauchard, hasta la aparición de los sistemas perno muñón vaciados metálicos, elementos que por primera vez permiten de un modo definitivo, independizar la solución estética de la recuperación de la pieza endodónticamente tratada. Haciendo especial hincapié en su forma, longitud, diámetro, adaptación, superficie, resistencia, propiedades y aleaciones en que usualmente se construyen

Enceramento de diagnóstico para um contorno anatômico / Diagnostic waxing for anatomic contour

Os autores através de uma revisäo da literatura, ressaltam a importância do enceramento de diagnóstico frente ao contorno das restauraçöes protéticas. Tentam deixar claro a importância do enceramento de diagnóstico tanto na fase de planejamento como durante o tratamento. Avaliam as teorias de contorno segundo seus autores, concluindo que devemos evitar o sobrecontorno das regiöes cervicais, através de um preparo adequado e um melhor entrosamento com o técnico de laboratório