Novel electrical conductivity device for osteotomy preparation for dental implants placement: A cadaver study.

OBJECTIVES: To evaluate the accuracy, safety, and anticipation effect of a novel electrical conductivity device (SG) in maxillary osteotomy preparation for placement of dental implants. MATERIALS AND METHODS: Thirty-seven osteotomies were prepared by three operators with different levels of expertise, using the SG protocol in the maxilla of six fresh frozen cadavers. A pre-op CT measurement of the length of bone in the desired implant location was taken and compared with the final length of the osteotomy created using SG during surgery. A comparison was made between the results of the different operators. RESULTS: The pre-op CT bone length measurements and the final depth assessment of the osteotomy with SG had a very high correlation level (0.977) with a significant mean difference of 0.639 mm (P < .0001), with the pre-op CT measurements being longer. The least experienced operator had placed the implants 0.924 mm less deep than the pre-op CT length measurements while the most experienced operator had placed the implants 0.244 mm less deep than the pre op CT length measurements. All implants were placed in the correct position and no breach of the sinus/nasal floor or buccal/palatine bone plates was detected. CONCLUSIONS: The SG electrical conductivity device offers the operator real-time monitoring during the surgical procedure. It provides a simple, safe, and sensitive method of detecting breaches, making it simple and safe for oral surgeons with different levels of expertise to use, with promising results.

Effect of Simplifying Drilling Technique on Heat Generation During Osteotomy Preparation for Dental Implant.

OBJECTIVES: To test the hypothesis that there would be no difference in heat production by reducing the number of drills during the implant site preparation relative to conventional drilling sequence. METHODS: A total of 120 implant site preparations with 3 different diameters (3.6, 4.3, and 4.6 mm) were performed on bovine ribs. Within the same diameter group, half of the preparations were performed by a simplified drilling procedure (pilot drill + final diameter drill) and other half using the conventional drilling protocol (pilot drill followed by graduated series of drills to widen the site). Heat production by different drilling techniques was evaluated by measuring the bone temperature using k-type thermocouple and a sensitive thermometer before and after each drill. RESULTS: Mean for maximum temperature increase during site preparation of the 3.6, 4.3, and 4.6-mm implants was 2.45, 2.60, and 2.95° when the site was prepared by the simplified procedure, whereas it was 2.85, 3.10, and 3.60° for the sites prepared by the conventional technique, respectively. No significant difference in temperature increase was found when implants of the 3 different diameters were prepared either by the conventional or simplified drilling procedure. CONCLUSIONS: The simplified drilling technique produced similar amount of heat comparable to the conventional technique that proved the initial hypothesis.

Evaluation of a New Ultrasonic Insert for Prosthodontic Preparation.

PURPOSE: This paper describes a new ultrasonic instrument (tipholder DB1 with crown prep tip inserts) designed to optimize prosthodontic margin repositioning and finishing. MATERIALS AND METHODS: The insert movement was assessed, and it was demonstrated that tipholder DB1 provides its inserts with an elliptical-like movement, making the entire insert surface able to cut. Then, 20 extracted teeth were prepared using tipholder DB1, sonic instruments, and traditional drills. Dental surface roughness produced using each of the three tools was measured using a roughness tester. Results were compared using univariate analysis of variance and Bonferroni post hoc test. RESULTS: The roughness produced using tipholder DB1 with crown prep insert presented no statistically significant differences compared to the roughness produced using sonic instruments and traditional drills. CONCLUSION: Tipholder DB1 with crown prep inserts is a promising treatment for margin repositioning and finishing.

The influence of residual root number and bone density on combined implant-residual tooth supported prosthesis after tooth hemisection: A finite element study.

The aim of the present study has been to analyze the influence of residual root number and bone density on the loading distribution of restorations combining implant and residual tooth after tooth hemisection using finite element analysis. Based on the image data of two patients, one has one distal root and the other has two distal roots in the mandibular right first molar, eight models were created (four models for each patient): a single crown was placed on the implant and residual tooth in two different bone densities; two separate crowns for the implant and residual tooth in two different bone densities. Vertical force of 100-N was applied on the crowns. The results show that the increase in number of residual roots decreased the magnitude of all biomechanical parameters. Higher values were observed in models with low bone density, especially in one distal root models. The maximum values of strains in spongious bone with the model (one distal root, low spongious bone density, a single crown was placed on the implant and residual tooth) even reached 9000µstrain. From a biomechanical point of view, when two residual roots exist, a single crown placed on the implant and distal half of the molar or two separate crowns for them seem to be an acceptable treatment option, regardless of the bone density. If there is one residual root and the bone density is low, the prosthesis which combines implant with the root might not be used.

Combined implant-residual tooth supported prosthesis after tooth hemisection: A finite element analysis.

Tooth hemisection preserves partial tooth structure and reduces the resorption of alveolar bone. The aim of this study was to analyze the feasibility of preserving a molar after hemisection and inserting a dental implant with different prosthetic superstructures by means of finite element analysis. First, the distance between the root of the mandibular second premolar and the distal root of the first molar were measured in 80 cone beam computed tomography (CBCT) data sets. Based on these data, the lower right posterior jaw segment was reconstructed and the geometries of the appropriate implant were imported. Four models were created: (1) Hemi-1: An implant (3.7×9mm) replaced the mesial root of the molar, and a single crown was placed on the implant and residual tooth. (2) Hemi-2: Two separate crowns were generated for the implant and the residual tooth. (3) Single: An implant (5.5×9mm) with crown replaced the whole molar. (4) FPD: A 3-unit fixed partial denture combined the distal residual part of the molar and premolar. The results indicated that stresses in the cortical bone and strains in the majority region of the spongious bone were below the physiological upper limits. There were higher stresses in implant with the Hemi-1 and Single models, which had the same maximum values of 45.0MPa. The FPD models represented the higher values of stresses in the teeth and strains in PDL compared to other models. From a biomechanical point of view, it can be concluded that a combination of an implant and residual molar after tooth hemisection is an acceptable treatment option.

Accuracy of a novel prototype dynamic computer-assisted surgery system.

OBJECTIVES: To implement and evaluate the accuracy of a prototype dynamic computer-assisted surgery (CAS) system for implant osteotomy preparation and compare its accuracy vs. three commercial static CAS systems and the use of an acrylic stent. MATERIAL AND METHODS: Eight osteotomies were prepared in radiopaque partially edentulous mandible and maxilla typodonts. After cone-beam CT acquisition, DICOM files were imported into a prototype dynamic, and three static CAS systems (NobelClinician, Simplant, and CoDiagnostiX). Implant placements were planned to replicate the existing osteotomies and respective guides were requisitioned, along with one laboratory-made acrylic guide. The eight osteotomies per jaw were transferred to one typodont pair mounted in a manikin in a clinical setting and the process was repeated for four additional pairs. The 80 (two jaws × eight holes × five pairs) osteotomies were filled with radiopaque cement in-between the testing series. Three clinicians experienced with the use of the static CAS softwares used in this study prepared each 400 (80 holes × five modalities) osteotomies. One clinician repeated the experiment twice, resulting in a total of 2000 (five clinicians × 400) osteotomies. The lateral, vertical, total, and angular deviations of the actual vs. the original osteotomies in the master typodonts were measured using stereo optical tracking cameras. Linear regression statistics using generalized estimating equations were used for comparisons between the five modalities and omnibus chi-square tests applied to assess statistical significance of differences. RESULTS: The prototype dynamic CAS system was as accurate as other implant surgery planning and transfer modalities. The dynamic and static CAS systems provide superior accuracy vs. a laboratory-made acrylic guide, except vertically. Both dynamic and static CAS systems show on average <2 mm and 5 degrees error. Large deviations between planned and actual osteotomies were occasionally observed, which needs to be considered in clinical practice. CONCLUSIONS: The prototype dynamic CAS system was comparably accurate to static CAS systems.

Precisão de medições lineares em tomografias computadorizadas por feixe cônico e helicoidal, realizadas em mandíbulas humanas / Accuracy of linear bone measurements cone-beam and spiral computed tomography in human mandibles

Introdução: a obtenção de métodos de imagem capazes de reproduzir com adequada precisão as dimensões maxilomandibulares é de vital importância para o diagnóstico e o planejamento seguro de procedimentos cirúrgicos. Objetivo: verificar, in vitro, a precisão de medições lineares de um exame de tomografia computadorizada helicoidal e de dois sistemas de tomografia computadorizada por feixe cônico. Método: dez mandíbulas humanas secas foram submetidas a três diferentes exames de tomografia: CBCT i-CAT, CBCT NewTom 3G e HCT helicoidal Picker CT Twin Flash. As medições realizadas diretamente na mandíbula foram feitas com um paquímetro digital, e as tomográficas por meio do software ImplantViewer 2.604. Foram mensuradas seis regiões de cada mandíbula seca, sendo agrupadas em duas regiões de primeiro molar inferior (Sítio PMI), duas regiões de primeiro pré-molar inferior (Sítio PPMI) e em duas regiões de incisivo lateral inferior (Sítio ILI). Resultados: nos sítios ILI e PPMI, as três tomografias estudadas demonstraram precisão semelhante entre si. No sítio PMI, a CBCT i-CAT mostrou-se mais precisa que as dos demais sistemas. Conclusão: pode-se concluir que nos sítios ILI e PPMI as três TCs estudadas apresentam limites de concordância e de precisão semelhantes, e que no sítio PMI a CBCT i-CAT apresentou um limite de concordância de menor amplitude, sendo mais precisa que a dos demais exames.

Availability of imaging methods able to accurately reproducing the maxillo-mandibular dimensions is important for diagnosis and safe planning of surgical procedures. Aim: The aim of this in vitro study was to verify the accuracy of linear measurements in images obtained with a system of spiral and two systems of cone-beam computed tomography (CT). Methods: Ten dry human mandibles were subjected to three different CT scans: I-Cat® CBCT, NewTom-3G® CBCT, and Picker® SCT. Measurements in the mandible were made with a digital caliper and measurements in the images were made with the ImplantViewer® software. Six regions were measured in each dry mandible, being distributed into two regions in each of the lower first molar (LFM), lower first pre-molar (LFPM), and lower lateral incisor (LLI) sites. Results: Similar accuracy was observed among the three images at sites LLI and LFPM. Measurements obtained with the I-Cat CBCT scan at site LFM were shown to be more accurate than the those obtained with the other two CT scan systems. Conclusions: It can be concluded that the three CTs studied herein showed similar limits of agreement and precision at sites LLI and LFPM, and I-Cat CBCT showed limits of agreement with smaller amplitude and greater accuracy than other examinations performed at site LFM. Conclusion: It can be concluded that the three CTs studied herein showed similar limits of agreement and precision at sites LLI and LFPM, and ICat CBCT showed limits of agreement with smaller amplitude and greater accuracy than other examinations performed at site LFM.

Utilization of digital technologies for fabrication of definitive implant-supported restorations.

The introduction 7 years ago of specially coded healing abutments dramatically simplified the task of obtaining implant impressions. Such coded abutments eliminated the need for impression copings, instead enabling supragingival impressions to be made and sent to the laboratory for fabrication of patient-specific abutments and restorations. Combining this technology with digital oral scanning has the potential to further simplify the time between impression-making and delivery of a definitive restoration, and it offers additional benefits to both patients and clinicians. This article explains how oral scanners can be used to obtain digital impressions of encoded healing abutments. A case report illustrating this approach is also presented.

New bone formation in nongrafted sinus lifting with space-maintaining management: a novel technique using a titanium bone fixation device.

PURPOSE: Sinus lifting without graft materials allows new bone formation in the sinus, but the amount of bone formation varies. This study aimed to investigate whether nongrafted sinus lifting using a titanium bone fixation device can promote bone formation in the sinus. MATERIALS AND METHODS: Patients with atrophic posterior maxillae jeopardizing implant stability were included. After nongrafted sinus lifting in combination with implant placement, repositioning of the bone window and additional space-maintaining management were performed by use of the bone fixation device. The primary variables recorded retrospectively included implant survival and preoperative and postoperative alveolar crest height with and without Schneiderian membrane perforation. Independent variables included patient demographics, position and dimension of the implants, complications, and follow-up period. The t test was used for comparing differences in bone levels. The implant survival rate was estimated by uses of Kaplan-Meier statistics. RESULTS: The study included 11 patients (4 men and 7 women) and a total of 21 implants. Radiographically, new bone formation around the implant was generally observed in accordance with the implant apex. Postoperative alveolar crest height (mean, 10.9 ± 2.2 mm) was significantly higher compared with residual alveolar crest height (mean, 4.7 ± 1.4 mm), and no significant difference in bone formation was seen according to membrane perforation. The cumulative survival rate was 95.2%. CONCLUSIONS: This nongrafted sinus-lifting procedure using a bone fixation device could attain predictable bone formation. Additional space-maintaining management using a bone fixation device in a nongrafted sinus lift offers a useful technique for promoting bone formation in the sinus.

Use of a titanium device in lateral sinus floor elevation: an experimental study in monkeys.

AIM: To evaluate the effect of a space-maintaining device fixed to the lateral wall of the maxillary sinus after the elevation of the sinus mucosa on bone filling of the sinus cavity. MATERIAL AND METHODS: Immediately after the elevation of the maxillary sinus Schneiderian membrane accomplished through lateral antrostomy in four monkeys, a titanium device was affixed to the lateral sinus wall protruding into the sinus cavity to maintain the mucosa elevated without the use of grafting material. The healing of the tissue around the implants was evaluated after 3 and 6 months. Ground sections were prepared and analyzed histologically. RESULTS: The void under the elevated sinus membrane, originally filled with the blood clot, was reduced after 3 as well as after 6 months of healing of about 56% and 40.5%, respectively. In seven out of eight cases, the devices had perforated the sinus mucosa. The formation of mineralized bone and bone marrow amounted to about 42% and 69% after 3 and 6 months, respectively. The connective tissue represented about 53% and 23% of the newly formed tissue after 3 and 6 months, respectively. CONCLUSIONS: New bone formation was found below the devices. However, shrinkage of the newly formed tissue was observed both after 3 and 6 months of healing. Hence, the space-maintaining function of the devices used in the present study has to be questioned.

Rehabilitation of the atrophic posterior maxilla with pterygoid implants: a review.

The purpose of this article is to review the literature published and to assess the success of treatment of patients with atrophic posterior maxilla with pterygoid implants. Studies from 1992 to 2009 on patients with atrophic posterior maxilla rehabilitated with pterygoid implants were reviewed. Those reporting clinical series of at least 5 patients with atrophic posterior maxilla (Class IV and V of Cawood and Howell), rehabilitated with pterygoid implants and fixed prosthesis, and with 12 months minimum follow-up were included. In each study the following were assessed: number of patients, number of implants, surgical technique, prosthetic rehabilitation, success rate, bone loss, complications and patient satisfaction. Thirteen articles were included, reporting a total of 1053 pterygoid implants in 676 patients. The weighted average success of pterygoid implants was 90.7%; bone loss evaluated radiographically ranged between 0 and 4.5 mm. No additional complications compared with conventional implants were found, and patient satisfaction level with the prosthesis was high. Pterygoid implants have high success rates, similar bone loss levels to those of conventional implants, minimal complications and good acceptance by patients, being therefore an alternative to treat patients with atrophic posterior maxilla. Two anatomical locations in which implants are placed in the retromolar area can be distinguished: the pterygoid process and the pterygomaxillary region. Implant lengths and angulations vary between these two techniques.

Types of implant surgical guides in dentistry: a review.

Various techniques have been proposed for the fabrication of surgical guide templates in implant dentistry. The objective of this paper is to review the associated literature and recent advancements in this field, based on design concept. An electronic and hand search of the literature revealed 3 categories, namely, nonlimiting, partially limiting, and completely limiting design. Most clinicians still adopt the partially limiting design due to its cost-effectiveness and credibility. Moreover, clinicians use cross-sectional imaging during the preimplant assessment of surgical sites.

Nasal floor augmentation for the reconstruction of the atrophic maxilla: a case series.

PURPOSE: The severely atrophic edentulous maxilla imposes a challenge for dental implant rehabilitation. Nasal floor augmentation (NFA) is a method of augmenting bone height in the anterior maxilla. Autogenous bone has been commonly used as a graft material. Because of variations in results and lack of insufficient studies reporting the use of bone substitutes to graft the nasal floor, this study aims to evaluate the survival and success of dental implants placed in nasally grafted maxillae with osteoconductive bone substitutes. MATERIALS AND METHODS: Six patients with completely edentulous maxillae and inadequate height in the anterior to support implants underwent NFA. The nasal floor was exposed through an intraoral approach and grafted with osteoconductive bone graft substitutes. Twenty-four dental implants were placed, restored with a bar-retained implant-supported overdenture after a traditional healing period, and followed up after prosthetic loading. Patient satisfaction was evaluated with a questionnaire, and responses were expressed on a visual analog scale from 1 to 10. Bone levels were quantified radiographically based on a score ranging from 1 to 3, where 3 represented the highest bone support. Implants were evaluated for thread exposure and soft tissue health and were considered successful if the following criteria were met: absence of mobility; lack of symptoms; bone score of 3; and healthy peri-implant soft tissue without thread exposure. RESULTS: The age of patients ranged from 48 to 84 years, with a mean of 71.2 years. Three patients underwent NFA and simultaneous implant placement, whereas the other 3 had a mean healing period of 6.5 months before implant placement. Post-loading follow-up ranged from 4 to 29 months, with a mean of 14.2 months. The implant survival rate was 100%, with no complications. Ninety-three percent of the responses to the treatment satisfaction questionnaire had a score of 7 or greater. Bone scores ranged from 2 to 3, with 87.5% of implants having a score of 3 and 12.5% having a score of 2. None of the implants had a bone score of 1. CONCLUSIONS: The use of osteoconductive bone substitutes for NFA, as shown in this small case series, is a reliable method for reconstruction of the anterior atrophic maxilla for implant-supported overdentures.

Simplistic partially limiting surgical guide for flapless implant placement: a case report.

The accurate positioning of implant in bone is important in order to meet the biological, esthetic, and biomechanical requirements of the prosthesis. This becomes crucial in flapless implant placement. The combination of bone sounding and use of a surgical guide will allow precise placement of a dental implant, abutment, and provisional restoration in a minimally invasive manner. A technique to transfer the diagnostic information to the surgical guide is described in this report. The chief advantage of the procedure is the ability to apply flapless implant placement surgery and immediate loading.

Piezoelectric vs. conventional implant site preparation: ex vivo implant primary stability.

OBJECTIVES: This study aims to determine differences in primary stability between implants placed in cortical bone following Piezoelectric or conventional site preparation, as assessed by resonance frequency analysis (RFA) and reverse torque testing (RTT). MATERIAL AND METHODS: Four fresh bovine ribs were acquired and surgical guides fabricated with five sites per rib (n = 20), for proper site preparation. Implant sites were prepared via conventional drilling technique as per manufacturer's instruction (Implantium) or via Piezoelectric (Mectron) implant site preparation using the Implant Prep kit. Twenty 10 mm long, 3.6 mm diameter Implantium implants were placed with 35 Ncm torque; 10 implants per preparation method. RFA was assessed via the Osstell Mentor. Five values were taken per implant. All implants where subjected to a reverse torque in increasing increments of 5 until 50 Ncm force was reached. RESULTS: The five RFA values per site were averaged and plotted by placement technique. A paired t-test statistical analysis was run. The average RFA values showed no statistical significance between the 10 test (RFA = 69.04 ± 5.11) and 10 control (RFA = 70.94 ± 6.41) sites (P > 0.05). All implants in both groups withstood RTT up to 50 Ncm force without movement and thus showed no statistical differences. CONCLUSION: Results of this ex vivo study imply that the Piezoelectric implant site preparation affords similar primary implant stability in comparison to conventional rotary instrumentation in cortical bone.

Fixed rehabilitation of severely atrophic jaws using immediately loaded basal disk implants after in situ bone activation.

Rehabilitation of severely atrophic jaws is facilitated when basal disk implants are used after activation of the future bony implant bed with a purpose-designed instrument (Osteotensor) 45 to 90 days before implant surgery. Fabrication of a highly rigid, screw-secured fixed prosthesis that acts as an external orthopedic fixator permits immediate functional loading. This protocol also represents a second chance for patients who have experienced complete implant loss and/or bone graft failure.

Rehabilitation of atrophic posterior maxilla with zygomatic implants: review.

The objective of this study was to review the published literature to evaluate treatment success with zygomatic implants in patients with atrophic posterior maxilla. Studies from 1987 to 2010 were reviewed. In each study, the following were assessed: indications for treatment, number of patients, number of implants, length and diameter of the implants, surgical technique, prosthetic rehabilitation, success rate, complications, and patient satisfaction. Sixteen studies were included, with a total of 941 zygomatic implants placed in 486 patients. The follow-up periods ranged from 12 to 120 months. Three different surgical techniques were used to place zygomatic implants: intrasinus implants with the classic sinus window technique, the sinus slot technique, and extrasinus zygomatic implants. The most common restoration used was fixed prosthesis, with either delayed loading after 3-6 months (89%-100% success) or immediate loading (96.37%-100% success). The weighted average success rate was 97.05%, and the most frequent complication was maxillary sinusitis. The general level of patient satisfaction was high. Zygomatic implants have a high success rate and constitute a suitable alternative to treat severe posterior maxillary atrophy.

Clinical application of stereolithographic surgical guide with a handpiece guidance apparatus: a case report.

The success of implant-supported restorations depends on the treatment planning and the transfer of planning through the surgical field. Recently, new computer-aided design and manufacturing (CAD/CAM) techniques, such as stereolithographic (SLA) rapid prototyping, have been developed to fabricate surgical guides to improve the precision of implant placement. The objective of the present case is to introduce a recently developed SLA surgical guide system into the rehabilitation of a 62-year-old male patient with mandibular edentulism. After obtaining a cone-beam computerized tomography (CBCT) scan of the mandible with a radiographic template, the images were transferred into a 3-dimensional (3D) image-based software for implant planning. The StentCad Beyond SLA surgical guide system, which is a combination of a currently used surgical template with pilot hollows and a surgical handpiece guidance apparatus, was designed to transfer a preoperatively defined implant position onto the surgical site without any drill-surgical guide contact. For the fabrication of this system, a surgical handpiece was scanned by a laser optical scanner and a mucosa-supported surgical guide was designed according to the patient's 3D model, which was attained from the CBCT images. Four dental implants were inserted through the SLA surgical guide system by a torque-controlled surgical handpiece to the interforaminal region via a flapless surgical procedure. Implants were assessed 3 months after surgery, and an implant-retained mandibular overdenture was fabricated. The present case emphasizes that CAD/CAM SLA surgical guides, along with CBCT images and scanning data, may help clinicians plan and place dental implants.