Does implant drill design influence the accuracy of dental implant placement using static computer-assisted implant surgery? An in vitro study.

BACKGROUND: The purpose of this in vitro study was to compare the accuracy of implant placement in model surgeries according to the design of the drills (straight drills or step drills) used to finalize the implant bed during pilot-guided static computer-assisted implant surgery (sCAIS). METHODS: Model surgeries were carried out on resin models randomly assigned to three study groups. Virtual planning software (coDiagnostiX 10.6, Dental Wings, Montreal, Canada) was used to plan the implant positions. In Groups 1 and 2, pilot-guided sCAIS was performed. Straight drills were used in Group 1, and step drills were used in Group 2 to finalize the implant beds. In Group 3, fully guided sCAIS was performed using a universal fully guided kit (RealGUIDE Full Surgical Kit 3DIEMME, RealGUIDE, Cantù, Como, Italy). A total of 90 dental implants (Callus Pro, Callus Implant Solutions GmbH, Nuremberg, Germany) were placed (six implants per model, five models per study group). The primary outcome variables (angular deviation, coronal global deviation, and apical global deviation) were calculated for all implants based on the comparison of the preoperative surgical plan with the postoperative scans. RESULTS: Group 2 (coronal global deviation, 0.78 ± 0.29 mm; apical global deviation, 1.02 ± 0.56 mm) showed significantly lower values of both global deviation variables than Group 1 (coronal global deviation, 0.95 ± 0.20 mm; apical global deviation, 1.42 ± 0.49 mm). However, there was no significant difference in angular deviation between Groups 1 and 2 (7.56 ± 2.92° and 6.44 ± 2.84°). Group 3 produced significantly lower values of all three primary outcome variables (angular deviation, 2.36 ± 0.90°; coronal global deviation, 0.59 ± 0.28 mm; apical global deviation, 0.90 ± 0.29 mm) than Group 1 and significantly lower angular deviation and coronal global deviation values than Group 2. CONCLUSIONS: The design of the drills used to finalize implant osteotomies during pilot-guided sCAIS influences dental implant placement accuracy. Using step drills instead of straight drills for final osteotomies decreases deviation from the surgical plan. The fully guided approach performed better than the pilot-guided sCAIS.

Soft tissue dimensional change using customized titanium healing abutment in immediate implant placement in posterior teeth.

BACKGROUND: The morphologic and dimensional alveolar bone is significant for resorption in the first 3 months after tooth removal because they restrict treatment outcomes with respect to function and esthetic. Following teeth extraction, the width and height of the alveolar ridge contour are reduced in both the horizontal and vertical dimensions. Following implant placement, the gingival morphology should be changed minimally compared to pre-extraction. Surrounding natural-like tissue is also an ultimate goal of the dental implant treatment, which is correlated with the cervical third contour on the anatomical tooth, for comfortable cleansing, food impaction avoidance, and esthetics. PURPOSE: To evaluate the peri-implant soft tissue changes after immediate implant placement (IIP) with the use of a customized titanium healing abutment in the posterior teeth. METHOD: Digital impressions using the intraoral scanner (MEDIT i500) were taken from 30 patients. Customized titanium healing abutments were designed and milled before extraction. Flapless extractions were done using surgical guides, 32 immediate implants placement were done in posterior areas, and healing abutments were placed. Soft tissues were scanned during pre-operation, and post-surgery during the 1st, 3rd, and 6th months. A 3D analysis program (Final Surface) evaluated the gingival margin distance, height, contour width, and volume in each period. SPSS was used to analyze the data with a p-value = 0.05. The between-time interval comparisons were done and the analysis was done using a Multivariate test. RESULTS: Customized titanium healing abutments used in immediate implantation maintained optimal peri-implant mucosa. In intermittent periods, there was no significant reduction in all aspects of the margin distances and heights. During the entire period, the margin height reduction on the buccal, lingual, mesial, and distal was 0.63 mm, 0.93 mm, 0.08 mm, and 0.24 mm, respectively, and contour width reduction on the buccal, lingual, and buccolingual was 0.59 mm, 0.43 mm, and 1.03 mm, respectively. There was a significant reduction in the total buccolingual contour width in the 1st month and total volume in the 3rd to 6th months. CONCLUSIONS: Immediate implant placement with customized titanium healing abutment can achieve the optimal peri-implant mucosa and this protocol is an alternative for soft tissue management.

A new inertial navigation system for guiding implant placement. An in-vitro proof-of-concept study.

The aim of this study was to assess the potential use of a new advanced inertial navigation system for guiding dental implant placement and to compare this approach with standard stereolithographic template guiding. A movement processing unit with a 9-axis absolute orientation sensor was adapted to a surgical handpiece and wired to a computer navigation interface. Sixty implants were placed by 10 operators in 20 jaw models. The 30 implants of the test group were placed in 10 models guided by the new inertial navigation prototype. The 30 implants of the control group were placed in another 10 models using a CAD-CAM template. Both groups were subdivided into experienced and non-experienced operators. Pre- and postoperative computer tomography images were obtained and matched to compare the planned and final implant positions. Four deviation parameters (global, angular, depth, and lateral deviation) were defined and calculated. The primary outcome was the angular deviation between the standard stereolithographic approach and the new inertial navigation system. Results showed no significant differences between both groups, suggesting that surgical navigation based on inertial measurement units (IMUs) could potentially be useful for guiding dental implant placement. However, more studies are still needed to translate this new approach into clinical practice.

Evaluation of Masticatory Performance and Patient Satisfaction Before and After Posterior Implant Restoration

ABSTRACT Objective: To evaluate the improvement in masticatory performances two weeks after posterior implant restoration. Material and Methods: Nine patients with missing first and second molars were included in the study. Masticatory performances were evaluated using subjective and objective methods utilizing color-changeable chewing gum and the visual analog scale (VAS) assessment. The subjects were asked to chew the color-changeable chewing gums before and two weeks after the posterior implant restoration. Their expectations regarding aesthetics and function were verified on the VAS before implant placement. Additionally, the VAS was used for the posttreatment completion rating two weeks after the implant restoration. Results: Significant differences in masticatory performance were noted at baseline (before implant posterior restoration) and two weeks after implant restoration (p<0.05). The posttreatment aesthetic and functional expectations ratings significantly exceeded the expectations (p<0.05). Conclusion: Masticatory performances were improved two weeks after implant restoration. In addition, the significant posttreatment ratings of the patients exceeded their initial expectations. In particular, patients with poor masticatory functions demonstrated significant improvements and satisfaction following implant restoration compared to those with good mastication. These findings indicate that a posterior implant restoration can increase the masticatory performance.

Reliability of Linear and Curvilinear Measurements on Cone-Beam Computed Tomography Images for the Evaluation of Implant Sites and Jaw Pathologies

ABSTRACT Objective: To evaluate the intra-examiner and inter-examiner reliability of linear and curvilinear measurements for the complete assessment of implant sites and jaw pathologies using Cone-Beam Computed Tomography (CBCT). Material and Methods: Fifty cone-beam computed tomographic images of patients were retrieved from the archives of Dentomaxillofacial Radiology. CBCT images taken for implant planning and evaluation of intrabony jaw pathologies (benign cyst/tumor) were included. Two expert oral and maxillofacial radiologists analyzed the images independently and made the measurements. The images for implant planning were analyzed for width, the height of the edentulous site, and the qualitative analysis of bone in the region. Jaw pathologies were assessed for linear dimensions and curvilinear measurements. Results: The inter-observer measurement error for implant site analysis ranged from 0.12 to 0.42 mm with almost perfect agreement (ICC: 0.94 to 1). The inter-observer measurement error for jaw pathology was 0.09 to 0.25 mm (ICC: 0.98-1). Curvilinear measurements showed perfect agreement between the observers. The intraobserver reliability for the various parameters used for the assessment of the implant site and jaw pathologies indicated almost perfect agreement. Conclusion: Reliability between the radiologists is high for various measurements on CBCT images taken for implant planning and jaw pathologies.

Short-Term Outcomes following Virtual Surgery-Assisted Immediate Dental Implant Placement in Free Fibula Flaps for Oncologic Mandibular Reconstruction.

BACKGROUND: Despite reports demonstrating feasibility of immediate dental implant placement in mandibular reconstruction with free fibula flaps for benign disease, this practice is not routinely used in the oncologic setting. The authors aim to demonstrate the safety of immediate dental implant placement for oncologic mandible reconstruction. METHODS: In 2017, the authors' center began immediate dental implant placement in free fibula flaps for oncologic patients undergoing mandibulectomy reconstruction. Immediate dental implant placement patients were compared to a historical cohort also reconstructed with computer-aided design and manufacturing technology beginning in 2011 (n = 34) as a noninferiority study design. Primary outcomes of interest included 90-day complications, time to radiotherapy, and time to and number of patients achieving dental restoration. RESULTS: Sixty-one patients underwent free fibula flaps following mandibulectomy using computer-aided design and manufacturing. Seventy-two dental implants were placed in the immediate dental implant placement cohort (n = 27). No differences were noted in major or minor 90-day complications between groups (p > 0.05). Radiotherapy was required in 55 percent in the immediate dental implant placement cohort versus 62 percent in the historical cohort, with no significant difference in time to radiotherapy (67.6 days versus 62.2 days, respectively). One dental implant was removed for nonosseointegration noted during vestibuloplasty. Fourteen (51.8 percent) immediate dental implant patients had complete dental restoration at 90 days compared with none in the historical cohort (p < 0.05). CONCLUSIONS: Immediate dental implant placement is a safe procedure with an unchanged short-term complication profile and no delay in radiotherapy initiation. Patients undergoing immediate dental implant placement are more likely to complete full dental rehabilitation. Long-term and health-related quality-of-life outcomes remain to be determined. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Technology at the service of surgery in a new technique of autotransplantation by guided surgery: a case report.

BACKGROUND: The aim of this case report was to use a surgical technique for autotransplantation of tooth using virtually planned 3D printed surgical templates for guided osteotomy preparation of the recipient of donor tooth. CASE PRESENTATION: An 18-year-old male patient received autotransplantation of the right mandibular third molar to replace an included right second molar. This procedure was based on guided implant surgery methods by superimposition of DICOM files and 3D data sets of the jaws. In order to design a 3D-printed template with the aid of a fully digital workflow; the third molar was conserved in PRGF during the surgical procedure and the tooth socket was prepared with a template and the help of a 3D-printed donor tooth copy in order to prevent iatrogenic damage to the donor tooth. This template and replica were manufactured using 3D-printing techniques. The transplanted tooth was placed in infra-occlusion and fixed with a suture splint and root canal therapy was performed 15 days later. The intervention was be accomplished by performing preplanned virtual transplantations with guided osteotomies to ensure accurate donor tooth placement in the new recipient site. The 24 months follow-up showed physiological clinical and radiologic results compatible with healing periradicular tissues. CONCLUSIONS: This approach enables the planning and production of a 3D printed surgical template using the latest diagnostic methods and techniques of guided implant surgery. These accurate virtually predesigned surgical templates and printed analogues of the donor tooth could facilitate autotransplantation, ensuring an atraumatic surgical protocol.

Effects of disinfection and sterilization on the dimensional changes and mechanical properties of 3D printed surgical guides for implant therapy - pilot study.

BACKGROUND: The purpose of this research was to investigate the effects of disinfection and three different sterilization methods on the dimensional changes and mechanical properties of three-dimensional (3D) printed surgical guide for implant therapy. The objective was to assess the effects of sterilization procedures in 3D printed drill guide templates with destructive and non-destructive material testing. METHODS: Fifteen identical drill guide templates were produced using a 3D printer. The surgical guides were classified into five groups: three controls, three disinfected (4% Gigasept®, 60 min), three plasma sterilized, three autoclave sterilized (+ 1 bar, 121 °C, 20 min), and three autoclave sterilized (+ 2 bar, 134 °C, 10 min). The templates were digitalized with a Steinbichler SCAN ST 3D scanner. Length was measured under an SZX16 stereomicroscope. A scanning electron microscope was used to study the surface morphology of the drill templates. The hardness, and flexural and compressive strength were measured to assess any changes in the physical characteristics of the material caused by sterilization. The drill guide templates were also examined with a Dage XiDAT 6600 X-ray. During the X-ray examinations, the following parameters were used: 100 kV voltage, 128 AVG averaging, 0.8 W power. One-way analysis of variance (ANOVA) was used to detect the difference between groups. RESULTS: Evaluation of the hardness measurements of the various specimens shows that the hardness of the material was not changed by the plasma sterilization (p = 0.0680), steam sterilization on 121 °C (p = 0.6033) or disinfection process (p = 0.1399). The statistical analysis revealed significant difference in hardness strength of the autoclave sterilized (134 °C) specimens (p = 0.0002). There was no significant difference between the goups regarding the scanning electron microscopic and stereomicroscopic examinations. There was no significant difference regarding the X-ray visibility of the templates to the effect of the disinfection (p = 0.7844), plasma sterilization (p = 0.4091) and steam sterilization on 121 °C (p = 0.9277) and steam sterilization on 131 °C (p = 0.093). The effect of the sterilization was the same in case of both flexural and compressive strength of the material. CONCLUSIONS: Our findings indicate that plasma sterilization and steam sterilization at 121 °C were both suitable for sterilizing the tested 3D printed surgical guides.

Surface modification via plasmid-mediated pLAMA3-CM gene transfection promotes the attachment of gingival epithelial cells to titanium sheets in vitro and improves biological sealing at the transmucosal sites of titanium implants in vivo.

Although titanium implants have been applied in dental clinics to replace lost teeth and to restore masticatory function for decades, strategies to design the surface of the transmucosal sites of implants to achieve ideal and predictable biological sealing following implantation remain to be optimized. In this study, we hypothesized that gingival epithelial cell (GEC) adhesion and new tissue attachment to titanium sheets/implants could be promoted by the release of plasmid pLAMA3-CM (encoding a motif of the C-terminal globular domain of LAMA3) from a titanium surface. To test this hypothesis, a chitosan/collagen (Chi/Col) coating was immobilized on the surfaces of titanium substrates with nanotube topography (NT-Ti) through cathodic electrophoretic deposition; it was found that pLAMA3-CM could be released from the coating in a highly sustained manner. After culturing on titanium with nanotube topography coated by Chi/Col with the plasmid pLAMA3-CM (Chi/Col/pLAMA3-CM-Ti), human GECs (hGECs) were found to effectively uptake the incorporated plasmids, which resulted in improved attachment, as evidenced by morphological and immunofluorescence analyses. In addition, Chi/Col/pLAMA3-CM-Ti induced better biological sealing at transmucosal sites following immediate implantation into Sprague-Dawley rats. Our findings indicate that the modification of titanium implants by plasmid-mediated pLAMA3-CM gene transfection points to a practical strategy for optimizing biological sealing around the transmucosal sites of implants.

Evaluation of the long-term stability of micro-screws under different loading protocols: a systematic review

Abstract: The aim of this systematic review was to investigate the association between the different factors of loading protocols and the long-term stability of micro-screws from biomechanical and histological viewpoints. Searches were performed on PubMed, Embase, Cochrane Library, Wanfang and CNKI databases for animal experiments comparing loading protocols and the long-term stability of micro-screws. Among 1011 detected papers, 16 studies met the eligibility criteria and were selected for analysis. Most studies showed medium methodological quality for evaluation of micro-screws' long-term stability. Five studies reported that loading would not destroy the long-term stability of micro-screws. Three studies indicated that low-intensity immediate loading or a 3-week minimal healing time was acceptable. Two studies reported that the loading magnitude was a controversial issue with regard to the micro-screws' long-term stability. Two studies suggested that counterclockwise loading could decrease the long-term stability of micro-screws. In conclusion, immediate loading below 100g force, healing time greater than 3 weeks, regular loading below 200g force and a clockwise direction of force supported the long-term stability of micro-screws. Further studies relating to the combination of varying loading conditions will be needed.

Accuracy of implant placement with a computer-aided fabricated surgical template with guided parallel pins: A pilot study.

BACKGROUND: A precise positioning for dental implant placement is important for further prosthesis fabrication and maintenance. Computer-aided surgery has been developed to transfer digitally planned implant positioning to the patient over the past decades. This study aimed to evaluate the accuracy of a computer-aided laboratory-fabricated surgical template. A further objective was to compare the accuracy between in vivo and in vitro groups. METHODS: A total of 20 implants were placed in the posterior tooth region through the aid of surgical templates on 17 partially edentulous patients in the in vivo group. The surgical template was fabricated in laboratory after virtual implant planning was completed using computer software. In the in vitro group, the same procedures were performed on the models without placing fixture with the same templates used in surgery. Deviations of the implant access at the implant platform level and apical region, as well as the angle deviations between the virtual planning data and the surgical results, were measured using a follow-up Cone Beam Computerized Tomography (CBCT) investigation, and image fusion with planning data. RESULT: The median deviation at platform level, apex and angulation was 0.95 mm (0.3-1.3 mm),1.35 mm (0.1-3.6 mm) and 3.92° (0.44-11.66°) respectively in the in vivo group; and 0.4 mm (0-1.0 mm), 0.65 mm (0.1-1.9 mm), 2.16° (0.17-6.91) respectively in the in vitro group. The in vitro group displayed significantly less deviation (p < 0.05). CONCLUSION: The data from this study shows that computer-aided laboratory-fabricated template may be a reliable tool for implant placement. However, the clinical conditions seem to affect the accuracy of the template.

Mini-implant selection protocol applied to MARPE

Abstract Introduction: Rapid maxillary expansion (RME) is the therapy of choice to correct skeletal transverse dimension in children and adolescents, associating orthopedic and dental effects. In an attempt to prevent the undesirable dentoalveolar effects and optimize the potential of skeletal expansion in individuals in advanced stages of skeletal maturation, the miniscrew-assisted rapid palatal expander (MARPE) was proposed by Lee et al. in 2010. Objective: This paper presents a systematized protocol for selection of miniscrews indicated for MARPE, by the evaluation of cone-beam computed tomographies (CBCT). Variables related with the bone and soft tissue thicknesses at the palatal regions of interest, as well as in relation to the fixation rings of miniscrews of the palatal expander are analyzed and discussed to provide better performance in the clinical practice.

Resumo Introdução: a expansão rápida da maxila (ERM) é a terapia de escolha para a correção da dimensão transversa esquelética em crianças e adolescentes, associando-se efeitos ortopédicos e dentários. Com a finalidade de prevenir os efeitos dentoalveolares indesejáveis e otimizar o potencial de expansão esquelética em indivíduos com estágios avançados de maturação esquelética, a técnica de expansão rápida da maxila assistida por mini-implantes (MARPE) foi proposta por Lee e colaboradores em 2010. Objetivo: o presente estudo apresenta um protocolo sistematizado para seleção de mini-implantes indicados para a MARPE, mediante avaliação de imagens de tomografia computadorizada de feixe cônico (TCFC). Variáveis relacionadas à espessura de tecido ósseo e tecido mole nas regiões de interesse do palato, bem como em relação ao anel de fixação dos mini-implantes do parafuso expansor, são analisadas e discutidas para proporcionar melhor desempenho na prática clínica.

Oral Implantology: Myths Exposed in Recent Research.

Today, a variety of surgical and prosthetic protocols, implant designs, and prosthetic devices are used for implant dentistry, employing many different dental technologies. With a plethora of options available, choosing an implant system has become highly challenging for practitioners. Having an understanding of the role of different implant design properties may help clinicians make informed decisions. This article provides an overview of factors affecting osseointegration and preservation of bone and discusses the importance of surgical and prosthetic treatments that respect the biologic width and avoid interventions, such as cementation, that may disturb the surrounding soft and hard tissues.

[Preliminary study on the automatic preparation of dental implant socket controlled by micro-robot].

Objective: To analyze the quantitative relationship between the number of layers of laser pulses and the amount of step in ultra-short pulse laser cutting of cortical bone, optimize the robot's vertical single stepping parameters, and to explore the feasibility of automatic preparation of dental implant cavity using robot controlling ultra-short pulse laser, in order to lay the foundation for automated dental implant surgery. Methods: Eight pig ribs were segmented into to make 16 specimens. Using the robotic surgical system and path planning software independently developed by our group, circular holes with a diameter of 4 mm were cut two-dimensionally in the rib segments to obtain the quantification relationship of the number of laser pulse layers (n) and the depth of two-dimensional (2D) cutting (d). When conducting the three-dimensional (3D) cutting procedure, the number of pulse layers were set to 5, 10, 15, 20, 25, 30, 35, 40, 45, 50 layers, the vertical single step amount was an integer value corresponding to the results of 2D cutting depth, and the number of pulses (n') corresponding to the minimum difference between the theoretical depth of cut and the actual depth of cut was obtained. The n' was taken as the most suitable single step pulse layer, the rib segment was cut, and the depth of single cut was measured while the integer value was taken as the most appropriate vertical single step amount (d'). The vertical parameters of laser single stepping were set as n' layer pulse and d' µm step size. The 3D cutting produces a cylindrical cavity with a diameter of 4 mm and a height of 2 mm to evaluate the 3D cutting accuracy (the difference between the measured value and the theoretical value of cutting diameter or depth). Ten 4 mm×3 mm implant holes were automatically prepared on the bilateral femurs of 5 Japanese big white rabbits, and ten 4 mm×3 mm implants made by 3D printer were artificially implanted, and the preparation effect of the implant cavities was evaluated. Results: The quantitative relationship curve between the number of laser pulses (n) and 2D depth of cut (d) showed a linear upward trend. The linear fitting obtained the quantitative relation function formula d=9.278 4 n±26.763 0, R(2)=0.988 9. The optimum number of single step pulse layers was 5 layers, and the vertical single step amount was 50 µm, so as to set the vertical parameters of a single step of a 3D cutting, and the 3D cutting diameter accuracy was (3.98±2.87) µm, with a depth accuracy of (15.42±5.44) µm. Automated preparation of 10 implant cavities on the femur of the rabbit were completed. When the implants were placed into the implant cavities, there was resistance, but they were fully seated and primary stability has been achieved after seating implant placement. Conclusions: The method of non-contact automatic preparation of dental implant cavities using robot controlling ultra-short pulse laser is feasible. By optimizing the single cutting process parameters, precise control of laser cutting cortical bone can be realized.

[Replacing heavily damaged molars with the use of 3D-techniques]. / Vervanging van ernstig beschadigde molaren met behulp van 3D-technieken.

Seriously damaged molars can be replaced by autotransplantation with the help of 3D techniques. In the present case, involving an 18-year old patient, 18, 38 and 48 were used to replace, respectively, 14, 36 and 37. Preoperatively, the width of the crowns and the root development of 18, 38 and 48 were analysed using 3D imaging. During the autotransplantation procedure, the new alveoli are formed with the help of replicas of the donor molars printed in 3D, in order to prevent iatrogenic damage to the actual donor molars.. The extra-alveolar time was less than 2 minutes for all donor molars. Postoperative follow-up showed physiologic integration of the transplanted molars. There was no ankylosis. Autotransplantation with the help of 3D techniques makes it possible to perform complex procedures with good results.

Influência do alinhamento das imagens por TCFC nas medidas lineares virtuais das relações entre implantes dentários: estudo laboratorial / The influence of different CBCT image alignment position on the virtual linear measurements of dental implant relationships: a laboratory study

Objetivo: verificar a variação das medidas lineares em função de angulações distintas dos implantes e dos alinhamentos diferentes das imagens de TCFC. Material e métodos: três mandíbulas artificiais de polietileno receberam 18 implantes dentários, com seis implantes em cada mandíbula, sendo: 1) dois angulados no sentido distal no lado direito posterior, 2) um angulado para vestibular e outro para lingual na região anterior, e 3) dois angulados no sentido mesial na região posterior esquerda. Com a mandíbula apoiada na mentoneira do equipamento e paralela ao plano horizontal, foram realizadas três aquisições tomográficas padronizadas, (voxel de 0,133 mm, FOV 6 x 8 cm, 89kV, 10 mA). Depois, foram realizadas uma medida perpendicular (da plataforma do implante ao rebordo mandibular) e outra inclinada (da plataforma do implante ao longo eixo do rebordo) nos cortes coronais e sagitais. As medidas foram realizadas com a base de mandíbula paralela ao plano horizontal e também após o volume ser rotacionado para o inferior no plano sagital. Os implantes foram numerados de um a seis e divididos em duplas. As medidas foram comparadas antes e após o alinhamento das imagens através do programa OnDemand3D. Resultados: foram observadas diferenças estatisticamente significantes entre as medidas realizadas nos implantes 1 e 2. Conclusão: as medidas lineares sofreram alteração em decorrência do posicionamento mandibular quando manipulado em software.

Objective: to verify the linear measure variation according to the distinct implants angulations and the different alignment from CBCT images. Material and methods: three polyethylene artifi cial models received 18 dental implants, 6 in each jaw, being: 1) two angled to distal on the right posterior side, 2) one angled to vestibular and another to lingual on the anterior region, 3) two angled to mesial way on the left posterior region. Each jaw was supported at a chinstrap of the equipment and parallel to the horizontal plane, and three standardized tomographic acquisitions were taken, (voxel size 0.133 mm, FOV 6 x 8 cm, 89kV, 10 mA). A perpendicular measure was made after the tomographic acquisitions (from the implant platform to the jaw border) and another inclined measure (from the implant platform to border long axis) both on coronal and sagittal acquisitions. Measurements were taken with the jaw base parallel to the horizontal plane and also when the volume was rotated to inferior on the sagittal plane. The implants were numbered from one to six and divided into couples. The measures were compared before and after image alignment by the OnDemand3D software. Results: statistically signifi cant differences were observed between the measurements performed on implants 1 and 2. Conclusion: the linear measurement values change in consequence of the jaw position when manipulated by the software.

Single mandibular implant study (SMIS) - masticatory performance - results from a randomized clinical trial using two different loading protocols.

OBJECTIVES: This multi-centre randomized controlled trial was conducted to investigate, whether the masticatory performance of elderly edentulous patients is improved by placement of a single implant in the midline of the edentulous mandible, and whether improvements differ with respect to the loading protocol, i.e., implant is loaded either directly or three months later after second stage surgery. METHODS: Edentulous seniors aged 60-89 years were screened according to inclusion and exclusion criteria and 163 underwent implant placement. Of those, 158 were randomly assigned either to the direct loading group A (n=81) or the conventional loading group B (n=77). Chewing efficacy was obtained before treatment, one month after implant placement during the submerged healing phase (only group B) and 1 and 4 months after implant loading. RESULTS: The masticatory performance increased over time in both groups. Four months after loading, a significant increase was observed for both groups compared to the baseline data without implant (p≤0.05). However, between the two groups, chewing efficiency did not differ significantly at any point in time (p>0.05). CONCLUSIONS: A single midline implant in the edentulous mandible increases masticatory performance significantly, independently from the loading protocol. CLINICAL SIGNIFICANCE: A single midline implant in the edentulous mandible increases masticatory performance. The loading protocol has no influence.

Study of the relationships between bur diameter and dental implant diameter / Estudio de las relaciones entre diámetro de fresas y diámetro de implantes dentales

The bur used to construct the bed where a dental implant is installed is extremely important to treatment success. The aim of this investigation was to analyze the relationship between bur diameter and implant diameter in different areas. A descriptive study was designed to analyze 5 commercial brands currently on the market. The manufacturer's instructions were followed to establish the size and type of bur indicated for the study implants, which were regular, with a width between 3.5 mm and 4.0 mm and a length from 12 mm to 13 mm. Drilling from the most apical region, the first measurement of width was established 3 mm cervically, the lower middle measurement 6 mm cervically, the upper middle measurement at 9 mm and the cervical measurement at 12 mm. A scanning electron microscope was used standardized for all measurements; the data were analyzed using the Shapiro-Wilk test and the t-test, having considering a value of p<0.05 for significant differences. At apical level, all the implants were wider than the bur. The greatest differences between bur width and implant were observed at cervical level, maintaining a relation where the implant was always wider. In medium-sized areas, it was observed that in some systems the burs have a larger diameter than the study implants. A significant relation was established in the apical, upper middle and cervical areas. Bur morphology is related to implant morphology; no implant system is the same as another in terms of the implant-bur relation.

La relación entre la fresa utilizada para construir el lecho donde se instala el implante dental tiene alta importancia en el éxito del tratamiento. El objetivo de esta investigación fue analizar la relación entre el diámetro de fresa y el diámetro de implantes en diferentes áreas. Se diseñó un estudio descriptivo analizando utilizando 5 marcas comerciales vigentes en el mercado; se siguió las instrucciones del fabricante para establecer el tamaño y tipo de fresa indicada para el implante en análisis, los cuales fueron de tipo regular considerando medidas en ancho de entre 3,5 mm y 4,0 mm y en largo de 12 mm a 13 mm. Desde la región mas apical de implantes y fresar se estableció 3 mm hacia cervical la primera medición de ancho, 6 mm hacia cervical la medición media inferior, a 9 mm la medición media superior y a 12 mm la medición cervical; para esta medición se utilizó microscopio electrónico de barrido estandarizado para todas las mediciones; los datos fueron analizados con pruebas estadísticas de Shapiro-Wilk y la prueba t-test, considerando un valor de p<0,05 para considerar diferencias significativas. A nivel apical, todos los implantes fueron mas anchos que las fresas utilizadas. A nivel cervical es donde se observan las mayores diferencias entre el ancho de la fresa y del implante manteniendo una relación donde el implante siempre es mas ancho. En áreas medianas, se observó que en algunos sistemas las fresas son de mayor diametro a los implantes analizados. Se estableció relación significativa en las regiones apical, media superior y cervical. La morfología de fresas presenta relación con la morfología implantaría; ningún sistema de implantes es igual a otro en términos de relación implante y fresa.

Biomateriales en levantamiento de seno maxilar para implantes dentales / Biomaterials in maxillary sinus lift for dental implants

RESUMEN: Objetivos El objetivo principal es describir las técnicas y condiciones en que se usan los diferentes biomateriales para los procedimientos de aumento del seno maxilar en implantes oseointegrados inmediatos o diferidos. Método Se realizó una búsqueda electrónica de textos completos desde el año 2010 hasta el 15 de agosto del 2014, y que respondieran la pregunta de investigación, utilizando diferentes buscadores y una manual en las revistas científicas de periodoncia. Se determinó el nivel de evidencia, calidad de reporte, sesgos de la literatura analizada y aspectos éticos. Resultados Se seleccionaron 17 estudios, 4 revisiones sistemáticas y 13 ensayos clínicos aleatorizados. Diez estudios comparaban los diferentes biomateriales disponibles entre sí, y no encontraron diferencias estadísticamente significativas en la nueva formación ósea. Un estudio examinaba la opción de no utilizar un biomaterial en el aumento de senos maxilares. Seis estudios indicaban que el uso de biomateriales adicionales no era significativo. Tres estudios concluyeron que no existían diferencias significativas entre uno o 2 tiempos quirúrgicos para realizar los procedimientos. Tres estudios comparaban la técnica quirúrgica de ventana lateral con la técnica indirecta, sin encontrar diferencias estadísticamente significativas, pero sí se asocia a un menor número de complicaciones a la técnica indirecta, especialmente al estar acompañada de la instalación de implantes cortos. Conclusiones No se describen diferencias entre los diferentes biomateriales utilizados en procedimientos de aumento de senos maxilares. El uso de biomateriales adicionales pareciera no ofrecer beneficios medibles al tratamiento. La técnica quirúrgica indirecta puede ser asociada a un menor número de complicaciones. Son necesarios más estudios de ensayos clínicos aleatorizados, con tamaños de muestra mayores, variables controladas y seguimientos a largo plazo para establecer conclusiones.

ABSTRACT: Objectives The main objective is to describe the techniques and conditions in which the various biomaterials are used for sinus augmentation procedures for immediate or delayed osseointegrated implants. Method An electronic search was conducted looking for papers published from 2010 to 15 August 2014 to answer the research question. Several search engines were used as well as a manual on scientific journals of periodontics. The level of evidence, quality reporting, biases of the analysed literature, and ethical aspects were determined. Results A total of 17 studies were selected, of which 4 were systematic reviews, and 13 were randomised trials. Ten different trials compared the available biomaterials with each other, and found no statistically significant differences in new bone formation. One study examined the option of not using biomaterials in the procedures. Six studies indicated that the use of additional biomaterials was not significant. Three studies concluded that there were no significant differences between 1 and 2 surgical times. Three studies compared the surgical technique of lateral window with the indirect technique, with no statistically significant differences, but the indirect technique was associated with fewer complications, especially when accompanied by the installation of short implants. Conclusions No differences between different biomaterials used in augmentation procedures for maxillary sinuses were described. The use of additional biomaterials does not seem to offer measurable benefits to the treatment. The indirect surgical technique may be associated with fewer complications. Further studies of randomised clinical trials, with larger sample sizes, controlled variables, and long term monitoring are needed to draw stronger conclusions.

Investigations on the accuracy of 3D-printed drill guides for dental implantology.

This article describes the computer-aided design/computer-aided manufacture (CAD/CAM) accuracy of dental drill guides for application in guided surgery. Today, the availability of three-dimensional (3D) desktop printers allows for the cost-effective production of drill guides by dental laboratories. Our investigations show the accuracy of produced guides by eliminating influencing factors that exist in the guided surgery workflow. To investigate this accuracy, a method was developed to evaluate the CAD/CAM production technology apart from sources of error from cone beam computed tomography (CBCT) scans, intraoral scans, software or human error. By using a CAD/CAM-milled idealized reference model, as well as CAD data from a scanned dental model with integrated reference spheres, drill guides with different offset values were designed using the coDiagnostiX® implant-planning software. The Bone Level Roxolid® SLActive® implant system (length 8 mm, diameter 3.3 mm) was chosen. The virtual position in relation to both the drill guide and the reference model was determined based on the planning data and exported STL files, respectively. Virtual and physical measurements were performed through the center coordinates of the used drill sleeves (T-sleeve: 5 mm), by applying a defined reference coordinate system (RCS) of the dental model. Drill guide templates were printed using a FotoDent® guide on a dental desktop printer (D30), based on a defined digital workflow. After insertion of the respective drill sleeves, surgical guides were secured on the reference models using quadrangular fixation, thus allowing a tactile measurement by applying a coordinate measurement device for determination of physical position relation. Through the central points of the drill sleeves, both the coronal and apical points of the planned implant drilling as well as angular deviation were calculated and reviewed against the CAD measurements. On average, a deviation of 0.25 degrees of the planned implant was detected.