Cluster behavior in dental implant failure - A scoping review.

PURPOSE: To provide an overview of cluster behavior in dental implant failure including the reported prevalence in modern roughened surface implants as well as the risk factors associated with cluster failures. MATERIAL AND METHODS: An electronic search for articles in the English language literature published from January 1, 2000, to March 8, 2023, was performed using PubMed, Embase, Dentistry and Oral Sciences, ProQuest, and Central search engines. Using a standardized systematic search process and predetermined inclusion and exclusion criteria in three stages, the final list of selected articles reporting on cluster behavior in dental implant failure was obtained. Cluster behavior was defined as the failure of two or more implants in the same patient within a 2-year period irrespective of the site. Data from the selected articles were reviewed, critically analyzed, interpreted, and reported. RESULTS: The initial electronic search resulted in 948 titles. After applying inclusion and exclusion criteria, the systematic search process resulted in five clinical studies reporting data on cluster behavior of dental implant failure with modern roughened surfaces. These five studies reported on a total of 9986 implants with 858 reported failures (early and late) over varying periods. Out of the 858 implant failures, 217 implants (25.2%) exhibited cluster behavior. The overall prevalence of cluster behavior of modern roughened surface implant failure was 2.1%.  The most common location risk factors reported were posterior maxilla, history of previous implant failures, poor bone quality, and occlusal overload. CONCLUSIONS: Cluster behavior occurs in 25% of modern roughened surface implant failures which is significantly less than machined surface cluster implant failures. Nevertheless, the overall prevalence of cluster pattern of implant failure of modern roughened surface implants is reasonably low at 2%.

Management of bleeding during dental implant surgery using a novel implant with an abbreviated drilling protocol: A clinical report.

Coagulopathy is a well-recognized complication in dental surgery in patients who use oral anticoagulants or some dietary supplements. Proper pre-operative diagnosis, medical consultation, timely management, and conservative treatment can decrease the incidence of such complications. Management of bleeding during dental implant surgery commonly involves conventional methods such as discontinuation of anticoagulant use, compression, styptics, and local anesthetic administration containing vasoconstrictors. This clinical report describes the successful management of a patient with a history of coagulopathy who was rehabilitated with complete arch fixed implant-supported prostheses with immediate loading. A novel implant design with a significantly abbreviated single drill protocol for osteotomy preparation was used in an outpatient setting. The novel protocol successfully decreased the overall bleeding and significantly reduced the intraoperative time for the surgical procedure. Additional considerations related to the novel implant design and osteotomy protocol, supplementary applications, and advantages of the protocol are presented in this article.

Comparison of electronic versus mechanical torque-limiting devices for dental implants: An in vitro study.

PURPOSE: To determine the accuracy of new electronic torque-limiting devices (ET) when compared to new and used conventional-style beam-type (BT) mechanical torque-limiting devices and hand-piece style (HS) mechanical torque-limiting devices. The secondary purpose was to compare any difference in accuracy between new and used mechanical torque-limiting devices, and any difference in accuracy when used on a straight versus an angled screw channel abutment. MATERIALS AND METHODS: A total of five torque-limiting devices were used to obtain 2000 readings under standardized conditions. An implant analog was fastened into a digital torque meter, to which an abutment was connected. Pre-determined torque values of 15 Ncm and 35 Ncm were applied, and actual torque values were recorded. A straight and an angled abutment were used to record 1000 readings each using the five torque-limiting devices. An overall Kruskal-Wallis test was applied to compare the median deviation among devices followed by a pairwise comparison ( = 0.05). RESULTS: For a target torque value of 15 Ncm on a straight abutment, the electronic device (ET) was statistically more accurate than the beam type (BT) new (p < 0.001) and used (p < 0.048) devices but less accurate than the hand-piece style (HS) used device (p < 0.001). On an angled abutment for a target value of 15 Ncm, the electronic device (ET) was statistically more accurate than hand-piece style (HS) new and used devices (p < 0.001). For a target torque value of 35 Ncm on a straight abutment, the ET was statistically more accurate than the HS new device (p < 0.001) but less accurate than the BT new device (p < 0.001). On an angled abutment for a target value of 35 Ncm, the electronic device (ET) was statistically less accurate than the beam-type (BT) new device (p < 0.001), the beam-type (BT) used device (p = 0.001), and the hand-piece style (HS) used device (p < 0.001). The electronic device (ET) was the only device accurate within the ISO standard of accuracy of 6% for each of the target torque value/abutment design combinations. There was no statistically significant difference related to the type of abutment used (angled vs. straight). CONCLUSIONS: Electronic torque limiting devices (ET) are an acceptable method for delivering torque for implant restorations for straight and angled abutments at 15 Ncm and 35 Ncm torque values. Conventional style beam-type (BT) mechanical torque-limiting devices are a simple, predictable, validated, and inexpensive tool for delivering accurate torque at 15 Ncm and 35 Ncm torque values. The hand-piece style (HS) mechanical torque-limiting devices are predictable to deliver 15 Ncm torque values.

A technique for digital alignment of cross-articulated casts in a computer-aided design software program for complete-mouth rehabilitation.

With the advent of computer-aided design and computer-aided manufacturing (CAD-CAM), dental restorations are no longer fabricated in an entirely analog fashion. Successful execution of complete-mouth rehabilitations requires articulation of definitive maxillary and mandibular casts with tooth preparations, as well as cross-articulation with the patient's interim restorations. These cross-articulated records serve as a guide for the dental laboratory technician in fabricating the definitive restorations. In the CAD-CAM workflow, cross-articulation and overlaying of a patient's interim casts over the definitive casts of tooth preparations poses some challenges because of loss of common anatomic data points such as incisive papilla, rugae, and the palate. This article describes a straightforward technique to overcome this common challenge, where a dental laboratory technician can predictably overlay the digitized interim casts to allow for cross-articulation and proceed with designing and fabricating the definitive restorations.

A technique for improved gingival esthetics on complete arch implant-supported acrylic resin prototype prosthesis.

An important step during the workflow of complete arch fixed implant-supported prostheses is the fabrication of an acrylic resin prototype prosthesis so that the patient can visualize the definitive treatment outcome or to be used as an interim prosthesis. The prototype prosthesis is typically designed digitally as a single file and is produced by milling from a solid block of white-colored prepolymerized acrylic resin. A common challenge in fabricating a resin-based prototype prosthesis is reproducing the natural appearance of the gingival architecture in gingiva-colored material. Current methods, including multicolored resin blocks, gingiva-colored stain, and layering with gingiva-colored composite resin, can be costly, time-consuming, and labor-intensive. This article describes a straightforward chairside technique that allows clinicians to fabricate an acrylic resin prototype prosthesis with appropriate gingival esthetics.

Implants in the pterygoid region: An updated systematic review of modern roughened surface implants.

PURPOSE: To determine the survival rates of modern roughened surface dental implants in the pterygoid region. METHODS: This systematic review was an update from a previously published systematic review in 2011, which largely reported data on older machined surface dental implants. An electronic search for articles in the English language literature published from January 1, 2010 to December 8, 2021 was performed using PubMed, Scopus, and CENTRAL search engines. After applying a systematic search process in three stages, the final list of selected articles on roughened surface pterygoid implants was obtained. Data from the selected articles were collated with data from pertinent articles on roughened implant surface from the previous systematic review. The combined data were then used for calculating the interval survival rate and cumulative survival rate (CSR) of pterygoid implants. RESULTS: The initial electronic search resulted in 1263 titles. The systematic search process eventually resulted in 10 clinical studies reporting on modern roughened surface pterygoid implants. These 10 studies reported on a total of 911 pterygoid implants with 39 reported failures over a 6-year period. The majority of failures (37) were reported during the first year time interval and a majority of them (30) occurred before loading of the pterygoid implants. Only two late failures were reported after loading, during the sixth-year time interval. The majority of implants were used for rehabilitation of full-arch fixed implant-supported prosthesis. At the maximum follow-up interval of 6 years, the CSR of pterygoid implants with roughened surfaces was 95.5%, which was 5% higher than reported in the previous systematic review which combined machined and roughed surface pterygoid implants. CONCLUSIONS: The survival rate of modern roughened surface dental implants in the pterygoid region is favorable at 95.5% over a 6-year period, and comparable to the existing evidence on survival of implants in other regions of the maxilla and mandible.

Clinical outcomes of implant-supported monolithic zirconia crowns and fixed partial dentures: A systematic review.

PURPOSE: To determine the survival rates of implant-supported monolithic zirconia crowns and fixed partial dentures (FPD). MATERIAL AND METHODS: An electronic search for articles in the English language literature published from January 1, 2001 to September 17, 2021 was performed using PubMed, Scopus, and CENTRAL search engines. After applying predetermined inclusion and exclusion criteria, the definitive list of selected articles was used for calculating the interval survival rate (ISR) and cumulative survival rate (CSR). Restoration failure in this study was defined as the fracture or compromise of any part of the ceramic restoration that required the removal or remake of the implant-supported restoration. RESULTS: The electronic search resulted in 457 titles. The systematic application of inclusion and exclusion criteria resulted in 14 clinical studies that addressed the clinical outcomes of implant-supported monolithic zirconia crowns and fixed partial dentures. Of these, 3 were randomized controlled trials, 5 were prospective studies, and 6 were retrospective studies. Follow-up periods ranged from 1 to 5 years. Of the 644 implant-supported monolithic zirconia restorations computed in this systematic review, there was only 1 reported failure of the monolithic zirconia restorative material over a follow-up period of up to 5 years, for a cumulative survival rate of 99.84%. At the maximum follow-up interval of 5 years, the cumulative survival rate for monolithic zirconia single crowns was 100% and the cumulative survival rate for monolithic zirconia fixed partial dentures was 99.60%. CONCLUSIONS: Implant-supported monolithic zirconia single crowns and fixed partial dentures have excellent short-term (<5 years) survival rates but the evidence for medium-term survival (>5 years) and beyond is lacking.

Management of Fractured Zirconia Complete Arch Fixed Implant-Supported Prosthesis Caused by Misfit Due to Diverse Implant Components: A Case Report.

Recently, monolithic zirconia complete-arch fixed implant-supported prosthesis (CAFIP) has been shown to be an effective means of managing patients with edentulism or terminal dentition. Prosthetic complications have been reported to be rare, as long as there is proper treatment planning, prosthetic space and careful attention during fabrication of the prosthesis. Few reports exist in the literature that have described the management of patients with fractured zirconia CAFIP. This case report describes the successful management of a female patient with a midline fracture of a monolithic zirconia CAFIP supported by 6 dental implants in the mandibular arch. The fractured prosthesis had adequate prosthesis thickness with no distal cantilever, and opposed a similar prosthesis in the maxilla. However, upon careful analysis, diverse implant components were identified as the primary contributory factor to prosthetic misfit, and subsequent fracture. This is a new factor that requires attention by clinicians and dental laboratory technicians due to the increased prevalence of patients with preexisting dental implants. This article describes the considerations related to diverse implant components and connections from different implant manufacturers, choice of favorable implant-abutment design, technique for mitigation, and importance of passive fit for zirconia CAFIP.

The Influence of Age and Facial Expression (Eye Open/Closed) On Maxillary Dental and Gingival Display.

PURPOSE: To assess if there are any differences in maxillary dentogingival exposure between different facial expressions (maximum smile with eyes open and eyes closed), age groups and both sexes. MATERIAL AND METHODS: Digital photographs of the lower third of the face of 120 subjects, belonging to 6 different age groups were taken. There were 20 subjects in each of the 6 age groups (20-30, 30-40, 40-50, 50-60, 60-70, and 70-80) which were comprised of 80 women and 40 men. Two standardized images of each subject were taken, one of maximum smile with eyes open, and the second of maximum smile with eyes closed. These 240 images were used to quantify a dentogingival exposure ratio (DER) for each tooth spanning the second bicuspids on either side, using standardized measurement techniques. Additionally, incidence of interdental papilla visibility was studied in a binary manner, and all data were studied with respect to various covariables of age, sex and type of facial expression using a generalized linear mixed effects model. A p-value < 0.05 was determined to be statistically significant. RESULTS: There was a statistically significant difference between the dentogingival exposure ratio (DER) for all images with eyes open and eyes closed per tooth location studied, across all age groups (p ≤ 0.001) and both sexes, suggesting that subject images of smiles with eyes closed had significantly higher dentogingival exposure. There was a decreasing trend of DER with increasing age groups when eyes were open (p = 0.005) and when eyes were closed (p = 0.042), suggesting that older subjects had lower dentogingival exposure. With respect to sex, there was no statistically significant difference in mean DER between males and females, when eyes were open (p = 0.430) and closed (p = 0.351). The incidence of interdental papilla exposure also differed significantly between images with eyes open and eyes closed across all age groups (p ≤ 0.001). However, the incidence of interdental papilla exposure decreased with age, only in images with eyes open (p < 0.001) but was not statistically significant among images with eyes closed (p = 0.127). With respect to sex, there was a significant difference in incidence of interdental papilla exposure in images with eyes open (p = 0.029) but no significant difference when eyes were closed (p = 0.782). CONCLUSIONS: Maxillary dentogingival exposure decreases with increasing age and is significantly higher when recording maximum smile with eyes closed, for all age groups and both sexes. As this is a simple and clinically reproducible facial expression, incorporating patient's maximum smiling images with eyes closed may be routinely necessary for complete and accurate data collection for prosthodontic treatment planning purposes.

Full arch monolithic zirconia prosthesis in a patient with bilateral cleft palate: A clinical report.

Adult patients with bilateral cleft lip and palate present unique challenges for prosthodontic treatment because of mobility of the premaxillary segment, oral-nasal communication, multiple missing and malpositioned anterior teeth, unfavorable soft tissues, and scar tissue underneath the maxillary lip. This clinical report describes the prosthodontic treatment of an adult patient with a terminal maxillary dentition and bilateral cleft palate, by using 5 dental implants and a 1-piece complete-arch fixed implant-supported prosthesis made of monolithic zirconia. The zirconia prosthesis aided in rigidly splinting not only the implants but also in orthopedically splinting the mobile premaxillary segment to the maxilla. Additional surgical and prosthodontic considerations in splinting the mobile premaxilla as well as biomechanical principles involved in management of such patients are also presented in this article.

Comparison of In Vitro Inactivation of SARS CoV-2 with Hydrogen Peroxide and Povidone-Iodine Oral Antiseptic Rinses.

PURPOSE: To evaluate the in vitro inactivation of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) with hydrogen peroxide (H2 O2 ) and povidone-iodine (PVP-I) oral antiseptic rinses at clinically recommended concentrations and contact times. MATERIALS AND METHODS: SARS-CoV-2, USA-WA1/2020 strain virus stock was prepared prior to testing by growing in Vero 76 cells. The culture media for prepared virus stock was minimum essential medium (MEM) with 2% fetal bovine serum (FBS) and 50 µg/mL gentamicin. Test compounds consisting of PVP-I oral rinse solutions and H2 O2 aqueous solutions were mixed directly with the virus solution so that the final concentration was 50% of the test compound and 50% of the virus solution. Thus PVP-I was tested at concentrations of 0.5%, 1.25%, and 1.5%, and H2 O2 was tested at 3% and 1.5% concentrations to represent clinically recommended concentrations. Ethanol and water were evaluated in parallel as standard positive and negative controls. All samples were tested at contact periods of 15 seconds and 30 seconds. Surviving virus from each sample was then quantified by standard end-point dilution assay and the log reduction value of each compound compared to the negative control was calculated. RESULTS: After the 15-second and 30-second contact times, PVP-I oral antiseptic rinse at all 3 concentrations of 0.5%, 1.25%, and 1.5% completely inactivated SARS-CoV-2. The H2 O2 solutions at concentrations of 1.5% and 3.0% showed minimal viricidal activity after 15 seconds and 30 seconds of contact time. CONCLUSIONS: SARS-CoV-2 virus was completely inactivated by PVP-I oral antiseptic rinse in vitro, at the lowest concentration of 0.5 % and at the lowest contact time of 15 seconds. Hydrogen peroxide at the recommended oral rinse concentrations of 1.5% and 3.0% was minimally effective as a viricidal agent after contact times as long as 30 seconds. Therefore, preprocedural rinsing with diluted PVP-I in the range of 0.5% to 1.5% may be preferred over hydrogen peroxide during the COVID-19 pandemic.

Rapid In-Vitro Inactivation of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Using Povidone-Iodine Oral Antiseptic Rinse.

PURPOSE: To investigate the optimal contact time and concentration for viricidal activity of oral preparation of povidone-iodine (PVP-I) against SARS-CoV-2 ('corona virus') to mitigate the risk and transmission of the virus in the dental practice. MATERIALS AND METHODS: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) USA-WA1/2020 strain, virus stock was tested against oral antiseptic solutions consisting of aqueous povidone-iodine (PVP-I) as the sole active ingredient. The PVP-I was tested at diluted concentrations of 0.5%, 1%, and 1.5%. Test media without any virus was added to 2 tubes of the compounds to serve as toxicity and neutralization controls. Ethanol (70%) was tested in parallel as a positive control, and water only as a negative control. The test solutions and virus were incubated at room temperature (22 ± 2 °C) for time periods of 15 and 30 seconds. The solution was then neutralized by a 1/10 dilution in minimum essential medium (MEM) 2% fetal bovine serum (FBS), 50 µg/mL gentamicin. Surviving virus from each sample was quantified by standard end-point dilution assay and the log reduction value (LRV) of each compound compared to the negative (water) control was calculated. RESULTS: PVP-I oral antiseptics at all tested concentrations of 0.5%, 1%, and 1.5%, completely inactivated SARS-CoV-2 within 15 seconds of contact. The 70% ethanol control group was unable to completely inactivate SARS-CoV-2 after 15 seconds of contact, but was able to inactivate the virus at 30 seconds of contact. CONCLUSIONS: PVP-I oral antiseptic preparations rapidly inactivated SARS-CoV-2 virus in vitro. The viricidal activity was present at the lowest concentration of 0.5 % PVP-I and at the lowest contact time of 15 seconds. This important finding can justify the use of preprocedural oral rinsing with PVP-I (for patients and health care providers) may be useful as an adjunct to personal protective equipment, for dental and surgical specialties during the COVID-19 pandemic.

Management of Maxillary Cluster Implant Failures with Extra-Maxillary Implants: A Clinical Report.

Late cluster implant failures can be one of the most devasting outcomes of implant therapy for patients. It can have anatomic, functional, psychological and financial consequences for patients, and sometimes the loss of residual bone can preclude subsequent implant placement. Fortunately, management of cluster implant failures in the maxilla can be mitigated by using implant anchorage from remote sites like zygomatic and pterygoid regions. Few reports exist in the literature that have described the management of cluster implant failure using extra-maxillary implants such as zygomatic and pterygoid implants. This case report describes the management of a female patient with bruxism who experienced late cluster implant failure in the maxilla after 9 years of function with an overdenture. Due to the loss of residual bone, subsequent implant therapy involved the use of bilateral zygomatic, pterygoid and anterior maxillary implants, which were immediately loaded and thereafter used to support a complete arch fixed implant-supported zirconia prosthesis.

Complete Arch Monolithic Zirconia Prosthesis Supported By Cobalt Chromium Metal Bar: A Clinical Report.

Complete arch fixed implant supported prosthesis made of monolithic zirconia is a popular treatment option with minimal complications, as documented in the literature over a 5-year period. One of the limitations of this material is its inability to be used when the span between adjacent implants is excessively long. A potential solution to mitigate this problem is to support the zirconia prosthesis with a metal substructure, which intrinsically has higher tensile strength. This clinical report describes the successful use of this prosthetic design in a male patient with bruxism and history of multiple implant failures in the maxilla. This resulted in a large anterior-posterior span between the anterior implants in the maxillary lateral incisor region and the distal implants in the pterygoid region. This article also describes the use of a split file digital workflow to scan the prototype prosthesis and then digitally design and mill the screw-retained cobalt chromium bar, as well as the overlaying of zirconia prosthesis which was retained by separate screws. This novel approach offers promise for management of the atrophic maxilla where implants with remote anchorage are used resulting in broader distribution of implants.

Milled cobalt-chromium metal framework with veneered porcelain for a complete-arch fixed implant-supported prosthesis: A clinical report.

Many materials have been introduced for the fabrication of complete-arch fixed implant-supported prostheses. This clinical report demonstrates the use of a computer numerically controlled (CNC), milled, 1-piece cobalt-chromium framework with veneered porcelain to treat a patient with dental implants placed with limited prosthetic space. This prosthodontic option combined the advantages of a digitally manufactured solution for a 1-piece metal framework and the excellent track record of metal-ceramic prostheses. An additional advantage of this option is its use in situations with reduced prosthetic space, where alternative materials such as monolithic zirconia are contraindicated.

Should Healing Abutments and Cover Screws for Dental Implants be Reused? A Systematic Review.

PURPOSE: To systematically review the current scientific evidence to assess if healing abutments and cover screws for dental implants can be resterilized effectively for reuse. A secondary purpose was to investigate if there has been any reported adverse biological or mechanical consequences to implants, or harm to patients with the reuse of healing abutments or cover screws. MATERIALS AND METHODS: An electronic search of the English language scientific literature was performed independently by multiple investigators using a systematic search process using the PubMed search engine and Cochrane database. After the application of predetermined inclusion and exclusion criteria, the final list of articles was reviewed to meet the various objectives of this review. RESULTS: The initial electronic search resulted in 657 titles and after the application of predetermined inclusion and exclusion criteria, six articles were identified that satisfied the study objectives. All six articles were observational studies that described a total sample of over 300 used healed abutments obtained from patients. Out of these, three studies showed that routine methods (mechanical, chemical, and steam) used for cleaning and sterilizing used healing abutments did not result in the complete removal of contaminants, while two studies showed that routine methods supplemented with an additional regimen resulted in adequate decontamination. One additional study showed that routine methods sufficiently resulted in adequate decontamination of used healing abutments. There were no true clinical studies identified. There were no studies identified in the literature that reported on any adverse consequences to dental implants, such as infections, bone loss, mechanical complications, implant failure, or harm to patients, by reuse of healing abutments or cover screws. CONCLUSIONS: Limited evidence suggests that routine methods used for cleaning and sterilization of used titanium healing abutments may not result in the complete removal of contaminants. However, the biological or mechanical implication of this finding is yet to be determined because presently there are no reports in the literature related to any unfavorable consequences to dental implants, or harm to patients by reuse of healing abutments or cover screws. Nevertheless, due to the popular clinical practice of reusing healing abutments to reduce cost to clinicians and patients, indiscriminate reuse of healing abutments should be avoided, until further supporting evidence is established.

Application of the palatogram technique to improve speech with complete-arch fixed implant-supported zirconia prostheses.

While maxillary complete-arch fixed implant-supported prostheses are a popular treatment for patients with complete edentulism or with a terminal dentition, how speech is best optimized with this treatment is unclear. One popular method used in complete denture therapy for immediate improvement of speech, as well as to reduce the speech adaptation period for patients, is the use of a palatogram technique. Contemporary biomaterials such as zirconia used for complete-arch fixed implant-supported prosthesis are difficult to adjust and modify. Therefore, the purpose of this article was to describe the application of the palatogram technique during the evaluation stage of the maxillary screw-retained milled prototype prosthesis (interim acrylic resin prosthesis) to improve the palatal contours and optimize contact areas of the tongue with the palatal aspect of the prosthesis. The modified interim prosthesis can then be used for copy milling the definitive zirconia prosthesis. This technique is useful when other prosthodontic factors related to speech, such as the occlusal vertical dimension and tooth positions, have already been optimized.

An analysis of anterior mandibular anatomy by using cone beam computed tomography: A study of 225 mandibular images.

STATEMENT OF PROBLEM: The anterior mandible has conventionally been deemed as a safe zone for dental implants. However, with the evolution of cone beam computed tomography (CBCT), several anatomic challenges have been identified that, if violated, can lead to surgical complications, including life-threatening hemorrhage. PURPOSE: The purpose of this observational clinical study was to obtain standardized average values for the location of the sublingual artery (SLA), submental artery (SMA), and mandibular incisive canal (MIC) and to determine whether differences exist between dentate and edentulous individuals. In addition, the prevalence of these anatomic landmarks on CBCT images was determined. An additional objective was to study the cross-sectional morphology of the anterior mandible. MATERIAL AND METHODS: CBCT images of 125 edentulous and 100 dentate patients were studied at the anterior mandible for the prevalence of SLA, SMA, and MIC. Measurements of these 3 structures were then made from the inferior cortical border of the mandible to the superior border of each structure to obtain average anatomic measurements. The cross-sectional shapes of anterior mandibles were then categorized, and the prevalence of each shape in this sample was calculated. RESULTS: The prevalence of SLA across all 225 CBCT images was 100% for edentulous patients and 98% for dentate patients. The SLA was located approximately 15 mm above the inferior border of the mandible. The prevalence of SMA was 94% for edentulous patients and 88% for dentate patients. The SMA was located approximately 5 mm above the inferior border of the mandible. The prevalence of MIC was 61% for edentulous patients and 59% for dentate patients. The MIC was located approximately 11 mm above the inferior border of the mandible in edentulous patients and approximately 14 mm above the inferior border of the mandible in dentate patients. Five distinct shapes were observed for the cross-sectional morphology of the anterior mandible: hourglass (1%), pear (53%), sickle (4%), ovoid (26%), and triangular (17%). The distance from the crest of the residual ridge to a minimum 6-mm width in the anterior mandible was approximately 4 mm. CONCLUSIONS: The SLA and SMA vascular structures were consistently identified in the anterior mandible on CBCT images, both in dentate and edentulous patients, whereas the mandibular incisive canal was not consistently visualized. Average values from the inferior border of the mandible to the SLA, SMA, and MIC were computable. The cross-sectional morphology of the anterior mandible is diverse in dentate and edentulous mandibles, with pear shaped being the most common in both. These findings should be taken into consideration when dental implants are planned in the anterior mandible.

Implant-Supported Immediately Loaded Complete Arch Rehabilitations with a Mean Follow-up of 10 Years: A Prospective Clinical Study.

PURPOSE: To evaluate the complication-free and failure-free survival rates of porcelain fused to zirconia (PFZ) and all-resin complete arch fixed implant-supported prostheses over a mean follow-up of 10 years. MATERIAL AND METHODS: Subjects with either all-resin or PFZ complete arch fixed implant-supported prostheses on 4 or 6 implants were followed prospectively for 10 years. Cumulative survival rates of prostheses without any catastrophic mechanical complications (resolved without replacing the prosthesis) and free of prosthesis failure (requiring the replacement or removal of the prosthesis) were calculated using life table analysis for up to 10-year period. Additional descriptive variables for various prosthesis events were recorded, such as sex, smoking and drinking status of subjects. RESULTS: A total of 36 subjects with a total of 68 prostheses (53 all-resin and 15 PFZ) were available for evaluation with a mean follow-up of 10 years (SD 1.47; range: 8-13 years). The study registered an overall 90% prostheses survival rate-78% for males and 94% for females; 91% for PFZ and 87% for all-resin; and a 31% complication-free prosthesis survival rate-13% for males and 38% for females; 29% for PFZ and 31% for all-resin at 10 years. A slight decrease in survival rate was identified in the first 3 years since the initial treatment (from 100% to 93%). The number of complications increased with time, especially after the 6th year after the initial treatment. CONCLUSION: Despite the number of reparable mechanical complications, the results confirmed the long-lasting features of both PFZ and all-resin complete arch fixed implant-supported prostheses over a 10-year period. There was however an increased number of mechanical complications after 6 years which may entail additional treatment cost for patients.

Relationship between Radiographic Misfit and Clinical Outcomes in Immediately Loaded Complete-Arch Fixed Implant-Supported Prostheses in Edentulous Patients.

PURPOSE: To examine if an uncorrected radiographically detected immediate postoperative misfit (implant level or abutment level) in immediately loaded conversion prosthesis plays a significant role in early implant or prosthesis failure. In addition, clinical characteristics related to type of arch, implant position, type of implant, implant orientation, type of connection, and type of surgery were analyzed relative to their relationship to early implant or prosthesis failure. MATERIALS AND METHODS: Immediate postoperative and subsequent follow-up panoramic radiographs of 425 arches with immediately loaded complete-arch fixed implant-supported prostheses were screened in a retrospective analysis. Implants with misfit and nonmisfit within a given arch were summarized separately with respect to each clinical characteristic and the difference between misfit and nonmisfit groups was tested using a mixed-effects logistic regression model with a patient-specific random intercept. A p-value <0.05 was determined to be statistically significant. RESULTS: A total of 2025 implants from 311 patients were identified in the 425 arches that were screened for radiographic misfit. A total of 48 implants with misfit were found within 33 arches (23 patients) for a 2.4% prevalence rate. Among the misfit implants, two failures were documented during the healing phase for an early implant survival rate of 95.8%. Five conversion prostheses with misfit fractured during the healing phase for early prosthesis survival rate of 84.8%. None of the clinical variables analyzed were significantly associated with the misfit status (p < 0.05). CONCLUSIONS: The results from this retrospective study showed that misfit in immediately loaded complete-arch fixed implant-supported prostheses may not play a detrimental role in the implant survival but may affect survival of the conversion prostheses.