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Statement of problem Rehabilitation of edentulous patients with severe maxillary atrophy is a clinical challenge. Although several treatment options are available, the implant-supported overdenture has been widely advocated. However vertical insertion implant-supported overdentures have drawbacks, including wear, aging, and the continuous maintenance of retention systems. Whether an implant-supported overdenture with a horizontal insertion pathway can overcome these problems is unclear. Purpose The purpose of this observational study was to determine the clinical and biological behavior of a new type of implant-supported overdenture with a horizontal insertion pathway over a mean clinical follow-up period of 6 years. Material and methods Ten study participants with an atrophic maxilla underwent rehabilitation with horizontal overdentures supported by 6 implants. Follow-up visits were scheduled at 3 months, 6 months, and annually thereafter. The variables analyzed were implant and prosthetic survival, peri-implant tissue behavior, mechanical complications, and patient satisfaction. Results The follow-up period ranged from 5 to 8 years, mean ±standard deviation 6.3 ±1.2 years. A total of 60 implants and 10 horizontal overdentures were placed. The clinical survival of the implants was 98.3% (mean peri-implant bone loss, 1.3 ±0.4 mm) and was 80% of the prostheses. Overall, mean patient satisfaction as assessed with a visual analog scale was 7.4, with 8.5 for esthetics and 9.5 for function. Conclusions The horizontal implant-supported overdenture provided a functional alternative to conventional prostheses.

A new technique of guided implant surgery is presented. A conventional complete denture is converted into both tomographic and surgical guides and later into an interim implant-supported fixed prosthesis. A plate derived from a computed tomography scan becomes the physical link between the virtual planning and tube positioning device. Furthermore, the interim placement of mini-implants adjacent to the symphysis region stabilizes the guide throughout the guided surgery. This technique reduces treatment time and costs.

Statement of problem Evidence provided by implant-supported mandibular overdenture research on different loading protocols is important. However, methodological inconsistency, as well as inadequate reporting of results, hampers a consistent decision in terms of clinical applicability. Purpose The purpose of this systematic review and meta-analysis was to evaluate whether immediate or early loading protocols can achieve comparable clinical outcomes when compared with a conventional loading protocol in edentulous patients rehabilitated with mandibular overdentures. Material and methods In accordance with the Participant, Intervention, Comparison, Outcome strategy, prospective clinical studies without restrictions as to language or follow-up period were included. The Cochrane collaboration and ROBINS-I tools were used for quality assessment and risk-of-bias evaluation. The follow-up for the different outcomes ranged from 3 to 168 months, with the focus on implant success and survival rates, marginal bone loss, bleeding on probing, probing depth, plaque index, and the implant stability quotient. Statistical analyses in which standard mean differences were applied with a 95% confidence interval when continuous data were included were performed. For dichotomous data, risk difference was adopted. Results The search strategy resulted in 14 234 references. Twenty-three studies fulfilled the inclusion criteria. Meta-analysis showed statistically significant differences for plaque index at 12 months (standard mean difference=0.284 [0.022, 0.545], P=.033, I2=35%), probing depth at 36 months (standard mean difference=0.460 [0.098, 0.823], P=.013, I2=0%), and on pooled results for plaque index (standard mean difference=0.157 [0.031, 0.284], P=.015, I2=18%) in which the conventional loading protocol presented lower indices than those of immediate loading protocol or early loading protocol. Implant stability quotient presented a statistically significant difference only at 3 months (standard mean difference=0.602 [0.309, 0.895], P .05) were not found. Conclusions Immediate loading protocol or early loading protocolfor mandibular overdentures has been determined to be a well-established treatment and worthy of consideration in clinical practice.

Statement of problem Single-implant–retained overdentures are an alternative treatment option for an edentulous mandible. However, evaluation of their clinical performance with an immediate loading protocol is lacking. Purpose The purpose of this prospective randomized controlled clinical study was to evaluate crest bone–level changes and patient satisfaction with mandibular overdentures retained by 1 or 2 titanium-zirconium (Ti-Zr) implants with immediate loading protocols after 1 year. Material and methods Thirty-six Ti-Zr implants were placed in 24 participants (single central implant in 12 participants and 2 interforaminal implants in 11 participants) by a single operator. LOCATOR attachments were used to retain the mandibular overdentures with an immediate loading protocol, and observations were made at 1 month and 1 year. Changes to the crestal bone level were evaluated with digital periapical radiographs. A 100-mm visual analog scale (VAS) was used to evaluate patient satisfaction. The Mann-Whitney U test was used to analyze the data. Results At 1 month, the mean crestal bone loss was 0.23 mm in the 2-implant group (n=22) and 0.39 mm (P=.181) in the single-implant group (n=11). At 1 year, the bone loss was 0.67 mm in the 2-implant group and 0.88 mm (P=.248) in the single-implant group. The mean VAS score for patient satisfaction level increased from 38.3% to 49.7% for single-implant participants and from 40.5% to 54.8% for 2-implant participants 1 month after implant placement (P=.250) and from 38.3% to 54.5% for single-implant participants and from 40.5% to 58.9% for 2-implant participants after 1 year (P=.341). Conclusions Single-implant–retained mandibular overdentures with an immediate loading protocol may represent a viable treatment option considering crestal bone–level changes and patient satisfaction compared with 2-implant–retained mandibular overdentures after 1 year of follow-up.

Statement of problem Long-term evidence of immediate loading of dental implants with bar overdentures is lacking. Purpose The purpose of this clinical study was to assess the clinical outcomes of immediate and conventional loading protocols of mandibular overdentures supported by 2 dental implants 14 years after initial placement. Material and methods Two groups of edentulous patients who received two TiUnite implants were enrolled in this study. In the experimental group (n=35), the implants were loaded immediately. In the control group (n=16), the conventional delayed loading protocol was followed. Participants of both the groups were treated with overdentures supported by a standardized resilient bar mechanism. Clinical oral health–related quality of life and patient satisfaction outcomes were recorded for 14 years after initial placement of implants and measured at various stages of treatment. Results Significant improvements in all outcomes were observed in both the groups compared with baseline, and this improvement was sustained over the duration of the study. No differences were noted in any of the study outcomes between the 2 groups. Conclusions Both the loading approaches provide comparable short- and long-term results. The results of this study confirm that immediate loading of implant-supported overdentures is a predictable treatment approach. Future studies should focus on assessing long-term clinical outcomes with mandibular overdentures in nonsplinted applications.

A novel computer-assisted surgery (CAS) technique that merges dynamic and static CAS approaches to treat completely edentulous patients with dental implants is described. Radiographic and surgical stents are designed with specific fiducial markers that are recognized by the static and dynamic CAS software program. During the surgical procedure, implants are placed following the static surgical guide and the indications from the dynamic navigation system. This technique combines the advantages of static and dynamic CAS approaches to allow accurate and predictable minimally invasive implant placement.

A consensus based on patients' perceptions as to whether to use overdentures or fixed prostheses to rehabilitate mandibular edentulous arches is limited.The purpose of this systematic review and meta-analysis was to compare the patient-reported outcome measures (PROMs) and clinical outcomes associated with implant-supported overdentures and fixed prostheses in edentulous mandibles.Nine electronic databases were searched for randomized clinical trials (RCTs) and nonrandomized clinical trials (N-RCTs). The risk of bias was assessed by the revised Cochrane risk of bias tool for RCTs (RoB 2) and N-RCT (ROBINS-I). Data sets for oral health-related quality of life (OHRQoL), satisfaction, survival rate, implant probing depth, and marginal bone loss were plotted, and the appropriate analyses were applied by using the Rev Man 5.3 software program. Certainty of evidence was also evaluated by means of the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach.Ten eligible trials were included and evaluated quantitatively. For 3 domains of OHRQoL, fixed prostheses showed significantly higher quality of life when compared with overdentures regarding functional limitation (P.001), physical disability (P=.001), and physical pain (P=.003). Fixed prostheses also improved satisfaction, when compared with overdentures for comfort (P=.02), ease of mastication (P.001), retention (P.001), and stability (P.001). The same pattern was observed for overall OHRQoL (P=.01) and satisfaction (P=.01) in which fixed prostheses improved patient satisfaction. Only ease of cleaning presented greater satisfaction for the overdenture group. Clinical parameters did not differ statistically (P.05) between both types of prosthesis.Fixed rehabilitations for mandibular edentulous patients seem to be a well-accepted treatment from the patients' oral health perspective. However, mandibular overdentures are no less efficient than fixed prostheses in terms of clinical outcomes.

This clinical report describes the rehabilitation of the maxillary arch of a partially edentulous patient with idiopathic root resorption, limited interarch distance, and a high smile line. Four implants were placed to provide a screw-retained fixed partial denture. The esthetic and functional challenges of a high smile line and limited interarch distance were addressed by using a combination of conventional and digital implant treatment technologies.

Implant-supported fixed prostheses in the edentulous maxilla can be difficult because of anatomic limitations and high esthetic demand. The choice between cement and screw retention depends on factors such as esthetics, occlusion, retrievability, and passivity. The choice is also often governed by the ability to manage technical or biologic complications. In the edentulous maxilla, because of the bone trajectory and resorption pattern, unfavorable implant angulations may be encountered. In such situations, a conventional screw-retained prosthesis is difficult to design. This article describes the restoration of edentulous maxillae for a series of patients with different complete-arch fixed prosthesis designs. The clinical guidelines, including indications, advantages, and limitations of each design, were discussed.

Zygomatic implants are an established treatment option in the management of the atrophic maxilla and in oncology rehabilitation, but evidence for their use in patients with a history of cleft palate is sparse. Zygomatic implants were used to retain a maxillary prosthesis in 7 edentulous patients with an unrepaired or repaired cleft lip and palate. Patient records were reviewed retrospectively to assess the survival rates. The mean follow-up time was 5 years with an implant survival of 100%. Most complications were associated with the prosthetic superstructures. This clinical report demonstrates that zygomatic implants can be successfully used to provide a maxillary prosthesis in patients with a history of cleft palate.

The conversion of a denture into an interim implant-supported, screw-retained restoration has become the standard method for immediate interim restoration in patients with complete edentulism. The most critical steps of the denture conversion process are the creation of appropriate denture access holes to prevent displacement of the denture by the interim cylinders and removal of the denture flanges to facilitate both good esthetics and accessibility for oral hygiene after the denture is connected to the interim cylinders. This article presents a digital technique for designing and fabricating an interim implant-supported, fixed prosthesis for edentulous patients. The interim prosthesis has cylinder access holes that are digitally prefabricated and a denture flange part that is designed to be easily sectioned. This technique facilitates more straightforward and efficient immediate restoration for edentulous patients after implant placement.

Mucormycosis is an opportunistic fungal infection that frequently infects sinuses, brain, or lungs and arises mostly in immunocompromised patients. Although its occurrence in the maxilla is rare, debridement and resection of the infected and necrotic area is often the best treatment but usually results in an extensive maxillary defect. Protocols for prosthetic obturation versus microvascular reconstruction have been established and used effectively in tertiary institutions for patients with such large defects. Aramany Class VI defects involving more than half of the palatal surface can be managed effectively by surgical reconstruction using microvascular free flaps as a platform for supporting bone-anchored prostheses. Providing fixed prostheses may offer advantages over a conventional obturator prosthesis in terms of hygiene, function, and esthetics. Nonetheless, fixed prostheses retained by endosseous implants in patients with reconstructive osteomyocutaneous flaps often require a sequential team approach by the surgeon and prosthodontist. This clinical report describes the reconstruction of a maxilla by using a scapular free flap with subsequent prosthetic rehabilitation in a patient with maxillary sinus infection secondary to mucormycosis.

This article describes a step-by-step digital protocol for the design and fabrication, through additive manufacturing, of a splinted framework and a custom tray for the impression of a complete-arch prosthesis supported by multiple implants. The protocol presented uses open source software to control the thicknesses of the custom tray, splinting material, and impression material during the procedure, reducing laboratory and chairside time and costs.

This clinical report describes the prosthetic and surgical management of a patient with a restricted oral orifice due to a perioral burn. Complete oral rehabilitation was achieved with maxillary and mandibular implant-supported fixed prostheses using a combination of digital and conventional impressions, design, and processing techniques.

Insufficient crown height space, particularly in the interforaminal region of edentulous ridges with knife-edge morphology, may prevent successful prosthetic rehabilitation. Such conditions require osteoplasty, which might complicate computer-guided implant placement. This clinical report illustrates the treatment of a patient with complete edentulism rehabilitated with a mandibular implant-supported fixed dental prosthesis by using a virtually guided approach. Both alveolar ridge reduction and prosthetically driven implant insertions were computer-guided by surgical stents to increase accuracy and predictability. This approach enabled the immediate loading of the implants with an interim prosthesis before the delivery of a definitive screw-retained fixed prosthesis. At the 1-year follow-up visit, clinical and radiographic examination revealed a stable outcome.

Statement of problem Limited data are available on the clinical outcomes of patients with edentulism treated with zirconia complete-arch fixed implant-supported prostheses (CAFIPs). Purpose The primary purpose of this retrospective clinical study was to study the failure rate of dental implants as well as the fracture rate of zirconia CAFIPs. The secondary purpose was to study the survival outcomes of patients with edentulism treated with zirconia CAFIPs as well as the rate of technical complications. Material and methods This retrospective clinical study from private practice included 128 patients rehabilitated between January 1, 2013, and December 31, 2016, with 1072 implants supporting 191 zirconia CAFIPs for single-jaw as well as double-jaw rehabilitations. All zirconia prostheses were of 1-piece design and were veneered with feldspathic porcelain only at the gingival region and therefore considered as predominantly monolithic. Additionally, all prostheses were bonded to implant manufacturer’s titanium cylinders that provided an intimate contact with the implants. The primary outcome measures were implant failure rate and prosthesis fracture rate. The secondary outcome measures were prosthodontic treatment survival rate and the incidence of technical complications with respect to monolithic zirconia CAFIPs. Cumulative survival rate (CSR) for implants and prostheses was calculated after a life-table survival analysis. Results Of the analyzed samples over a 4-year period, at least 288 implants and 49 prostheses had a minimum of 4 years of follow-up. A total of 18 implant failures were noted (13 in maxilla, 5 in mandible), yielding a CSR of 97.6% for implants. One fracture of the zirconia prosthesis was recorded, yielding a CSR of 99.4% for the prostheses over the 4-year period. Another 3 prostheses required remaking because the supporting implants failed, and 1 prosthesis was remade because the lack of passive fit resulted in a CSR of 96.8% for the prosthodontic treatment itself. During the 4-year period, 1 zirconia prosthesis had a technical complication related to the debonding of titanium cylinders, and 2 prostheses had fractured screws, which were resolved successfully. No zirconia prostheses had chipping of the veneered gingival porcelain. Conclusions Findings from this retrospective clinical study from private practice showed that prosthodontic treatment of edentulous patients with a 1-piece, complete-arch fixed implant-supported zirconia prosthesis with veneered porcelain restricted to the gingival region had high survival rates for implants and prostheses. Minimal technical complications related to this type of treatment for edentulous jaws and no chipping of the veneered gingival porcelain were encountered.

A female patient, now aged 17 years, was diagnosed with rhabdomyosarcoma (RMS) in the right pterygopalatine fossa when she was 3 years old. The RMS was successfully treated by excision, but the subsequent radiation and polychemotherapy resulted in the complete anesthesia of the distribution area of the right trigeminal nerve and loss of vision in the right eye. The patient also experienced pain in the mandibular joints and masticatory muscles. Panoramic radiographs displayed a multiple agenesia of the permanent teeth and underdeveloped apices. Treatment involved the fabrication of a complete maxillary denture. A removable device was fabricated to evaluate her response to an occlusal vertical dimension increase of 6 mm and provide a stable intercuspal position. After wearing the prosthesis for 6 months, the patient reported that she was completely free of symptoms.

The production of removable dentures from intraoral scans has been problematic. In addition, the digital design and fabrication of a single-arch denture cannot be routinely managed. The workflow presented provides a proof of concept that an optical intraoral scan of the edentulous maxilla is feasible and that a functional single-arch maxillary denture can be designed and fabricated using a digital protocol.

The genial tubercle is a clinically palpable landmark in the mandible and can be identified in cone beam computed tomography (CBCT). Its location can be used to measure the safe zone in the interforaminal region of the mandible. These measurements may be helpful for implant treatment planning in patients with complete edentulism.The purpose of this clinical study was to evaluate the safe distance in the interforaminal region of the mandible measured from the genial tubercle level for implant osteotomy in a Chinese-Malaysian population.A total of 201 Digital Imaging and Communications in Medicine (DICOM) files were selected for the study from the CBCTs of dentate or edentulous Chinese-Malaysian adult patients with ongoing or completed treatments. Measurements were made with implant planning software. The anatomy of the whole mandible was assessed in the coronal cross-sectional, horizontal view and in panoramic view. Measurements were obtained in millimeters on one side by locating and marking a genial tubercle and then marking the mesial margin of the mental foramen and the anterior loop of the inferior alveolar nerve. The corresponding points of these landmarks were identified on the crest of the mandibular ridge to measure the linear distances. All the measurement steps were repeated on the other side. The linear distance of 2 mm was deducted from the total distance between the genial tubercle and the anterior loop separately for left and right side measurements to identify the safe zone. The mixed 2-way analysis of variance (ANOVA) test was used to analyze side and sex-related variations.The mean safe zone measured at the crestal level from the genial tubercle site on the left side of the mandible was 21.12 mm and 21.67 mm on the right side. A statistically significant (P.05) difference was found between the left and right sides of the safe zone measurements in both men and women. No statistically significant differences were found in the safe zone between men and women on either the left or right side (P=.655). The minimum distance from the genial tubercle to the right side safe zone in women was 12.82 mm and 14.99 mm in men; however, on the left side, the minimum distance was observed to be 14.81 mm in women and 15.54 mm in men.The safe zone related to the genial tubercle was 21.12 mm on the left side and 21.67 mm on the right side, with no significant sex-related variations. Within the same individuals, a significant difference was found in the safe zone between the left and right side.

A technique is described to generate a framework for an implant-supported fixed complete denture. The main advantage of the described technique is the low production cost of a framework that has high strength, passive fit, and distinct retentive structures for each denture tooth.

Edentulism has been associated with sensoneurinal hearing reduction, but whether hearing is improved by the provision of an implant-retained overdenture is unclear.The purpose of this pilot clinical study was to provide completely edentulous participants with implant-retained complete overdentures and to evaluate the effect on their hearing ability by pure tone audiometry (PTA).Fifteen completely edentulous first-time denture wearers were enrolled, and their hearing was evaluated with PTA for air conduction and bone conduction at 6 time intervals: before denture insertion (R1), after denture insertion (R2), 1 month after denture insertion (R3), on the day of suture removal after implant surgery (R4), 3 months later, at the time of loading (R5), and 1 month after implant loading (R6). The Friedman test was performed to find significant differences in the measurements from the completely edentulous state to rehabilitation with a complete denture and an implant-retained complete overdenture. The post hoc Tukey test was used for multiple comparisons (α=.05).Significant differences were found between R1 and R6, between R2 and R6, between R3 and R6, and between R4 and R6 in PTA in multiple comparisons (P.05). The post hoc test revealed significant difference in the R1and R6 and R3 and R6 pairs (P.05) at 500 Hz, 1 kHz, and 8 kHz, whereas only between R1 and R6 (P.05) at 2 kHz for the air conduction test. In the bone conduction test, a significant difference was observed between the R1 and R6 and the R3 and R6 pairs (P.05) at 500 Hz and 4 kHz, but only between R3 and R6 (P.05) at 1 kHz and 2 kHz.The study showed that the placement of dental implants improved hearing acuity via the acoustic pathway through air and bone conduction.

Statement of problem Current in vivo and in vitro research has difficulty keeping pace with the rapid evolution of materials, protocols, and designs of the complete-arch fixed implant-supported prosthesis. Purpose The purpose of this survey was to determine the current prevalence of usage of various treatment modalities and materials for complete-arch fixed implant-supported prostheses. Material and methods From November to December of 2018, a survey invitation was sent out to members of the Pacific Coast Society for Prosthodontics (PCSP). The survey was hosted online, and asked a series of 18 questions related to the materials, protocols, and design preferences for complete-arch fixed implant-supported prostheses. The prompt included the suggestion that answers should be based on preferences for ideal treatment of a hypothetical completely edentulous patient seeking fixed, implant-supported prostheses, assuming sufficient native bone and an opposing complete-arch fixed implant-supported prosthesis. Results Of 133 invitations sent via email, 45 (34%) surveys were started and 48 (36%) were completed. Pertinent results are summarized in histograms with color coding in each answer group to indicate the total number of arches the person had treated (a proxy for experience). Most respondents were in private practice (73%) and had completed more than 21 arches of fixed implant-supported prostheses (62%). Nearly half (49%) of the respondents preferred 6 implants in the maxilla, while the preferred number in the mandible was highly varied between 4 (33%), 5 (27%), and 6 (29%) implants. Three-fourths (75%) preferred bone-level implant designs, and the plurality was ambivalent on the use of a platform-switched design (48%). Two-thirds (67%) preferred to deliver a complete-arch fixed provisional prosthesis at the time of surgery. Two-thirds (67%) preferred to make the definitive impression by using rigidly splinted, open-tray copings. While most (67%) preferred to fabricate the definitive maxillary and mandibular prostheses with identical occlusal materials, the specifics of material selection between arches varied greatly. In the maxilla, a plurality preferred anatomic contour zirconia with titanium bases (33%). In the mandible, a plurality preferred laboratory-processed resin with denture teeth over a milled metal bar (32%). Conclusions While a wide range of protocols, designs, and materials exist in the use of the complete-arch fixed implant-supported prosthesis, these results provide a snapshot of current clinical preferences in the Western United States.

This clinical report describes a treatment protocol for completely edentulous patients using digital implant planning for an all-on-4 treatment of both the maxilla and mandible as well as the use of a shape-memory alloy retention system to secure a complete-arch restoration to the mandible.

Whether clinical or demographic variables affect the perception of treatment in terms of quality of life and satisfaction is unknown.The purpose of this prospective study was to make an evidence-based assessment of the treatment outcomes (patient- and clinically based) of locator-retained mandibular overdentures.This prospective observational study assessed patients with edentulism who had worn mandibular overdentures supported by 2 implants and retained by the locator system for at least 1 year of functional life (N=80). Medical histories were reviewed, and patients underwent oral examinations. Prosthetic clinical outcomes and patient well-being were registered using the Oral Health Impact Profile 20 (OHIP-20) and Oral Satisfaction Scale (OSS).Patient well-being scored an overall OHIP-20 score of 19.0 ±14.0 of 80 (the higher the score, the greater the impact and the worse the oral health-related quality of life); overall oral satisfaction was 8.3 ±1.7 of 10. Women suffered greater social impact (0.8 ±1.0) and disability (0.4 ±0.8) than men (0.4 ±0.7 versus 0.2 ±0.4, respectively). Impact on well-being was inversely proportional to both patient age and the age of the prosthesis (r=-0.25; P.01). Implants had been placed on average 73.6 ±39.2 months previously, showing a survival rate of 82.5%. Most of the overdentures had been functioning for over 60 months. Relining (46.3%), readjustments (82.5%), and changes of nylon retention (1.5 ±1.8 per patient over 60 months of use) devices negatively influenced well-being.Mandibular overdentures produced good results with regard to quality of life and oral satisfaction, but attention should be paid to factors affecting clinical outcomes and patient well-being.

Chediak-Higashi syndrome (CH-S) is a rare genetic immunodeficiency disorder. Fewer than 500 individuals with CH-S have been reported worldwide in the past 20 years. The dental management of patients in whom CH-S has been diagnosed has been rarely reported and only in the form of a case report. All reports addressed the severe periodontal disease found in those patients, and most studies concluded that periodontal treatment had an unfavorable prognosis. As a result, complete edentulism at an early age because of severe periodontal disease is expected. The purpose of this report was to present 2 patients with CH-S seeking oral rehabilitation after early tooth loss and severe bone resorption as a manifestation of severe periodontal disease. The treatment used bilateral zygoma implants and an all-on-4 concept. The complications encountered and management with a 5-year post-surgery follow-up are also presented.

Ceria-stabilized zirconia/alumina nanocomposite (Ce-TZP/A) exhibits an elasticity equivalent to that of cobalt–chromium alloy and a flexural property that is superior to that of yttria-tetragonal zirconia polycrystal. Therefore, the use of Ce-TZP/A for the fabrication of removable dental prosthesis frameworks is being studied. However, the current English literature does not include any clinical report on the use of Ce-TZP/A for the fabrication of the entire framework. This clinical report describes the process and outcomes of fabricating a mandibular implant-supported overdenture and a maxillary complete denture with Ce-TZP/A as the framework material.

Restoring a severely resorbed maxilla is challenging because of poor bone quality and the resorptive pattern that follows tooth loss. When bone augmentation is not possible, implants are placed in suboptimal positions, making the prosthetic rehabilitation more complex. This report presents the steps used to rehabilitate a severely resorbed maxilla with divergent implants, using an implant-supported 2-piece screw-retained prosthesis.

Statement of problem Using intraoral scans for removable dentures has been questioned because of a suggested lack of accuracy. However, data regarding the accuracy of digital intraoral complete-arch scans are sparse, present some methodological issues, and mostly come from in vitro studies on dentate casts, which are very different from edentulous arches. Purpose The purpose of this clinical study was to evaluate 3D differences between intraoral scans (IOS) and conventional impressions of edentulous arches by means of digital analysis. Material and methods Ten maxillary and 10 mandibular edentulous arches were investigated. For each of them, IOS was performed, and a custom tray was digitally designed based on these scans. Trays were built by using a 3D printer and used to make a conventional impression with a polysulfide impression material. The conventional impression was scanned immediately by using the same intraoral scanner and by the same dentist. Standard tessellation language (STL) files of IOS and the scans of the corresponding conventional impressions (CIS) were superimposed with a 2-phase best-fit alignment in a reverse engineering software program. The corresponding full-scan, 3D mean distance was measured. This procedure was repeated after trimming the IOS and CIS to eliminate peripheral areas not present in both files, as well as nonmatching areas caused by practical aspects related to obtaining the IOS (mobile tissue stretching) and the conventional impressions (mobile tissue compression and folding at the margin of impression), which could have impaired alignment and, consequently, measurement accuracy. The mean distance between the full and trimmed IOS and CIS was statistically investigated, and subgroup analysis was performed for the maxillary and mandibular arches. The statistical significance of the differences between the 2 impression methods was also investigated. Results The full-scan mean distance between the IOS and CIS (−0.19 ±0.18 mm) was significantly different from that of the trimmed scan mean distance (−0.02 ±0.05 mm), with no significant differences for maxillary and mandibular arches. The differences between the IOS and CIS were statistically significant for full scans; they were not significant for trimmed scans, except for the maxillary subgroup. Conclusions The mean distance between the IOS and CIS may be significantly different if they are not properly superimposed. The mean distance (−0.02 ±0.05 mm) between the IOS and CIS falls within the range of mucosa resilience. Thus, 3D differences between the IOS and CIS can be attributed to the different physics behind the 2 impression methods and not to defects in accuracy of one method compared with the other. The size of the measured difference between the 2 impression methods was not statistically significant and was not clinically significant for removable denture fabrication.

Statement of problem Simplified edentulous jaw impression techniques have gained popularity, while their validity has not yet been evaluated. Purpose The purpose of this clinical study was to compare the trueness of maxillary edentulous jaw impressions made with irreversible hydrocolloid (ALG), polyvinyl siloxane (PVS), PVS modified with zinc oxide eugenol (ZOE) (PVSM), and an intraoral scanner (TRI) with a conventionally border-molded ZOE impression (control). Material and methods Twelve edentulous maxillary impressions were made with the impression techniques. The analog impressions were scanned using a laboratory scanner, imported into 3-dimensional comparison software, and superimposed against the corresponding control. Trueness was evaluated by calculating the effective deviation known as root mean square (RMS) for the entire surface (ES) and for specific regions of interest such as peripheral border, inner seal, midpalatal suture, ridge, and posterior palatal seal. The secondary outcomes for this study were the patients' perception of the impression techniques. Statistical analyses with the Wilcoxon tests were carried out (α=.05). Results For ES, significant differences were found when comparing ALG (1.21 ±0.35 mm) with PVS (0.75 ±0.17 mm; P=.008), PVSM (0.75 ±0.19 mm; P=.012), and TRI (0.70 ±0.18 mm; P=.006) but not among the other groups. Significant differences were found for peripheral border when comparing ALG (2.03 ±0.55 mm) with PVS (1.12 ±0.32 mm; P=.006), PVSM (1.05 ±0.29 mm; P=.003), and TRI (1.38 ±0.25 mm; P=.008), as well as TRI and PVSM (P=.028). Significant differences were also found for inner seal when comparing ALG (0.74 ±0.36 mm) with PVSM (0.52 ±0.13 mm; P=.041), as well as TRI (0.8 ±0.25 mm) versus PVS (0.56 ±0.14 mm; P=.005) and PVSM (P=.005). The difference at the ridge was significant when comparing PVS (0.18 ±0.07 mm) with PVSM (0.28 ±0.19 mm; P=.015) but not among the other groups. A significant difference was also found for posterior palatal seal when comparing PVS (0.55 ±0.41 mm) with PVSM (0.60 ±0.43 mm; P=.034). Patient perceptions showed significantly better satisfaction scores for ALG (1.83 ±2.03) and PVS (3.17 ±2.40) than for TRI (4.08 ±2.71), PVSM (4.58 ±2.35), and ZOE (6.83 ±1.75). Conclusions Edentulous impressions made with PVS, PVSM, and TRI had similar deviations and may yield clinically acceptable results. Irreversible hydrocolloids are contraindicated for definitive impression making in completely edentulous jaws.

Statement of problem Consensus is lacking regarding the optimal number of implants for supporting complete-arch prostheses with good survival rates and lower prosthetic complications and marginal bone loss. Purpose The purpose of this systematic review was to evaluate the influence of the number of implants used for complete-arch prostheses with at least 5 years of follow-up. Material and methods A search was performed in the PubMed/MEDLINE, Scopus, and Cochrane Library databases according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) criteria and was registered in The International Prospective Register of Systematic Reviews (CRD42016048468). The following was the population, intervention, comparison, outcome (PICO) question: Does the number of implants influence the longevity of complete-arch prostheses? Results Nineteen studies including 1006 patients with a mean age of 61.44 years were selected for evaluation. The number of implants per jaw ranged between 2 and 9 in the maxilla, mandible, or both jaws. For implant survival rate in complete-arch prostheses with fewer than 5 implants per jaw, the pooled weighted event rate was 1.4% (I2=25.26%; P=.211) and 4.2% (I2=81.35%; P Conclusions The current systematic review indicated no relationship of the number of implants used to support a complete-arch prosthesis with implant survival rate, prosthesis survival rate, prosthesis complications, or marginal bone loss in studies with follow-up periods of between 5 and 15 years.

The introduction of new techniques and new technology has been directly related to successful outcomes in implant dentistry. Merging information from high-quality cone beam computed tomography images and detailed prosthetically driven digital planning translates into computer-guided surgery. A surgical template is a guide used to assist in the proper surgical placement and angulation of dental implants. However, a surgical guide not only facilitates implant placement but can also be used for other purposes, including diagnosis, treatment planning, and even second-stage surgery. In situations where multiple implants have been placed through computer-guided implant surgery, the preexisting surgical template can be used to perform the second-stage surgery with a flapless approach if the patient's soft tissue condition permits.

This article describes a technique for obtaining an accurate complete-arch digital scan for an edentulous patient. To achieve this, an auxiliary polymeric device that simulates a denture is designed, fabricated, and placed in the mouth. This device, having the geometry of a typical dental arch, facilitates the digitalization of the edentulous complete arch. This is because the change in radius of the curvature (change of geometry) enables the scanner to perform a more accurate alignment. Initially, the necessary location of the implants is acquired, and then the soft tissue is added. This technique can achieve accurate complete-arch digital scans. Distances between implants are closer to the gold standard when using this auxiliary geometry piece than those obtained without using it.

Although different impression techniques have been advocated for complete denture prosthodontics, objective studies that predict their effect on alveolar bone resorption are lacking.The purpose of this prospective clinical pilot study was to objectively evaluate the effect of complete dentures fabricated by different impression techniques on mandibular residual ridge resorption in individuals with different bone mineral density.Ninety-six participants with edentulism, selected according to inclusion criteria, underwent bone mineral density assessment and were divided into normal, osteopenic, and osteoporotic groups. Half of the participants in each group were provided with dentures fabricated by selective pressure impression technique (subgroup SIT), and the other half were provided with dentures fabricated by mucostatic impression technique (subgroup MIT). Computed tomographic scans of the mandible were made at denture delivery and 1 year after prosthesis use to assess alveolar bone height and width difference at marked locations at and after denture delivery. The data obtained were analyzed with the Student t test (α=.05).Significantly less reduction in mandibular ridge height and width was found in the MIT versus the SIT subgroups in both osteopenic and osteoporotic participants (P.05). No significant subgroup difference was found for normal bone mineral density group, although resorption increased in height and width for the SIT subgroup.Mandibular residual ridge resorption was reduced for dentures fabricated using the mucostatic impression technique compared with the selective pressure impression technique in individuals with diminished bone density.

This clinical report describes the prosthetic rehabilitation of a patient with a mandibular implant-supported complete fixed dental prosthesis with limited interocclusal restorative space. The problem was manifested by repeated fractures of the acrylic resin teeth and distortion of the supporting framework. The definitive restoration included a custom computer-aided design and computer-aided manufacturing (CAD-CAM) titanium framework with the lingual cusps and most of the occlusal table of the mandibular posterior teeth milled in titanium as part of the framework. An esthetic CAD-CAM milled denture base along with teeth was bonded over this framework.

An appliance was designed and fabricated by using computer-aided design and computer-aided manufacturing (CAD-CAM) and 3-dimensional (3D) printing to combine a custom tray with an intraoral Gothic arch. This helped simplify centric relation recording and combined definitive impression making and centric relation recording into a single step.

After a stroke, patients frequently show compromised swallowing, mastication, and speech, as well as unfavorable motion and deviation of the tongue and mandible. The dentist can improve the oral rehabilitation of a patient with deteriorated facial and oral muscles after a stroke by incorporating orofacial myofunctional therapy. This report describes a method for tongue exercises and correction of mandible deviation in an edentulous patient after a stroke by using a pearl on a wire in the anteriomedian palatal part of the maxillary denture.

An ill-fitting complete denture has the potential to create pain and discomfort as well as conceal or confound the diagnosis of other primary sources of orofacial pain such as trigeminal neuralgia. Guidelines of the American Academy of Orofacial Pain offer an evidence-based approach for the assessment, diagnosis, and management of orofacial pain. A complete and accurate differential diagnosis is paramount to the success of treatment as well as to the circumvention of unnecessary therapy. The purpose of this clinical report was to emphasize an evidence-based approach to the diagnosis and treatment of orofacial pain in a patient with edentulism and a history of prolonged denture wear.

Conometric retention has recently been proposed as an alternative to cemented or screwed retentions for fixed restorations. Conometric copings can only compensate for slightly nonparallel placement without interfering with retention. This article describes a method of using digital scanning technology to facilitate computer-guided implant planning when an immediate restoration supported by conical abutments is planned with a guided-welded approach. The procedure involves importing the scan data of the conometric coping and of the definitive cast obtained from the surgical template into the implant planning software. This approach increases the accuracy of computer-guided implant planning and reduces the time needed for the surgery.

Statement of problem Computer-aided design and computer-aided manufacturing (CAD-CAM) high-density polymers (HDPs) have recently been marketed for the fabrication of long-term interim implant-supported fixed prostheses. However, information regarding the precision of fit of CAD-CAM HDP implant-supported complete-arch screw-retained prostheses is scarce. Purpose The purpose of this in vitro study was to evaluate the marginal discrepancy of CAD-CAM HDP complete-arch implant-supported screw-retained fixed prosthesis frameworks and compare them with conventional titanium (Ti) and zirconia (Zir) frameworks. Material and methods A screw-retained complete-arch acrylic resin prototype with multiunit abutments was fabricated on a typodont model with 2 straight implants in the anterior region and 2 implants with a 30-degree distal tilt in the posterior region. A 3-dimensional (3D) laboratory laser scanner was used to digitize the typodont model with scan bodies and the resin prototype to generate a virtual 3D CAD framework. A CAM milling unit was used to fabricate 5 frameworks from HDP, Ti, and Zir blocks. The 1-screw test was performed by tightening the prosthetic screw in the maxillary left first molar abutment (terminal location) when the frameworks were on the typodont model, and the marginal discrepancy of frameworks was evaluated using an industrial computed tomographic scanner and a 3D volumetric software. The 3D marginal discrepancy at the abutment-framework interface of the maxillary left canine (L1), right canine (L2), and right first molar (L3) sites was measured. The mean values for 3D marginal discrepancy were calculated for each location in a group with 95% confidence limits. The results were analyzed by repeated-measures 2-way ANOVA using the restricted maximum likelihood estimation and the Satterthwaite degrees of freedom methods, which do not require normality and homoscedasticity in the data. The between-subjects factor was material, the within-subjects factor was location, and the interaction was included in the model. Tukey tests were applied to resolve any statistically significant source of variation (overall α=.05). Results The 3D marginal discrepancy measurement was possible only for L2 and L3 because the L1 values were too small to detect. The mean discrepancy values at L2 were 60 μm for HDP, 74 μm for Ti, and 84 μm for Zir. At the L3 location, the mean discrepancy values were 55 μm for HDP, 102 μm for Ti, and 94 μm for Zir. The ANOVA did not find a statistically significant overall effect for implant location ( P =.072) or a statistically significant interaction of location and material ( P =.078), but it did find a statistically significant overall effect of material ( P =.019). Statistical differences were found overall between HDP and the other 2 materials ( P ≤.037). Conclusions When the tested materials were used with the CAD-CAM system, the 3D marginal discrepancy of CAD-CAM HDP frameworks was smaller than that of titanium or zirconia frameworks.

Statement of problem Casting difficulties have led to the limited use of titanium in dental prostheses. The selective laser melting system was recently developed to fabricate biomedical components from titanium alloys. However, the fabrication of a titanium alloy framework for a maxillary complete denture by selective laser melting has not yet been investigated. Purpose The purpose of the study was to fabricate thin titanium alloy frameworks for a maxillary complete denture with a selective laser melting system and to evaluate their hardness and microstructure. Material and methods A cast of an edentulous maxilla was scanned with a dental 3-dimensional cone-beam computed tomography system, and standard triangulation language data were produced with the DICOM Viewer (Digital Imaging and Communications in Medicine). Two types of metal frameworks for complete dentures were designed with 3-dimensional computer-aided design software. Two titanium alloy frameworks, SLM-1 and SLM-2, were fabricated from these designs with the selective laser melting system. Plate-shaped specimens were cut from the central flat region of SLM-1, SLM-2, and as-cast Ti-6Al-4V (As-cast). Vickers hardness testing, optical microscopy, and x-ray diffraction measurements were performed. Results Thin titanium alloy frameworks for maxillary complete dentures could be fabricated by selective laser melting. The hardness values for SLM-1 and SLM-2 were higher than that for the as-cast specimen. Optical microscopy images of the SLM-1 and SLM-2 microstructure showed that the specimens did not exhibit pores, indicating that dense frameworks were successfully obtained with the selective laser melting process. In the x-ray diffraction patterns, only peaks associated with the α phase were observed for SLM-1 and SLM-2. In addition, the lattice parameters for SLM-1 and SLM-2 were slightly larger than those for the as-cast specimen. Conclusions The mechanical properties and microstructure of the denture frameworks prepared by selective laser melting indicate that these dentures are appropriate for clinical use.

Statement of problem Maxillary resections jeopardize the stability and functional stress generated by implanted-supported prostheses. Purpose The purpose of this study was to evaluate the stability and functional stress caused by implanted-supported obturator prostheses in simulated maxillary resections of an edentulous maxilla corresponding to Okay Classes Ib, II, and III, with no surgical reconstruction. Material and methods Implants were positioned in the residual maxilla, and bar-clip retention systems were designed for each experimental model. The 3-dimensional models of the maxillary resection and corresponding implanted-supported obturator prosthesis, constructed from a computed tomography scan, were used to develop a finite element mesh. Loads were simultaneously applied to the occlusal (80 N) and anterior (35 N) platforms corresponding to the prosthetic teeth. Qualitative analysis was based on the scale of maximum principal stress; values obtained by means of quantitative analysis were expressed in MPa. Results The implant-supported obturator prostheses tended to rotate toward the surgical resection, the region with no osseous support. Tensile and compressive stresses in the gingival mucosa and in the cortical bone increased as the osseous support and the numbers of implants and clips diminished. Conclusions All evaluated bar-clip retention systems displayed a tendency toward dislodgment of the obturator prosthesis, increasing as the osseous resection area amplified. The osseous tensile and compressive stresses resulting from the bar-clip retention system for Okay Classes Ib, II, and III maxillectomy may not be favorable to the survival rate of implants.

Statement of problem It is hard to identify the most favorable retainer type and the denture design when considering strain levels around implants and in edentulous ridges for implant overdentures (IOVD). Purpose The purpose of this study was to evaluate the strain transmitted to the implants and edentulous ridges by Marburg double crown (MDC)-retained IOVD as opposed to bar and ball-retained IOVD and the efficiency of a rigid major connector in the maxilla. Material and methods An in vitro maxillary model was prepared with 4 implants, with strain gauges placed distally to each implant and also in the anterior and posterior edentulous ridges. Five overdentures were fabricated for each MDC and each ball and bar attachment retainers. Vertical loads of 280 N were applied bilaterally on the first molar region. Then the palatal bars of each IOVD were disconnected, and loading procedures were repeated for the prostheses. Results No significant difference was observed among the MDC and the bar and ball-retained IOVD, with and without a rigid bar according to the data taken from both the implants and edentulous ridges. However, when the strain values attained from each strain gauge separately were considered, a slight difference was observed around the implants of ball-retained overdentures and in the edentulous ridges of MDC-retained overdentures. Conclusions Within the limitations of this in vitro study, MDC-retained maxillary overdentures with 4 parallel and symmetrically placed implants can be used safely without a rigid major connector as with bar and ball-retained IOVD with regard to the strains generated in the edentulous ridge and around implants.

The transition of patients from failing dentition to complete-arch implant rehabilitation often means that the patient is rendered edentulous and has to wear a removable complete denture for a time. Many patients find this objectionable. A staged treatment approach provides a fixed interim prosthesis for use throughout the rehabilitation process, allowing patient comfort and prosthodontic control. This clinical report describes a staged approach protocol with a new type of interim prosthesis. The prosthesis is supported by hopeless teeth and the soft tissues of the maxillary tuberosities and mandibular retromolar pads for the complete-arch implant rehabilitation of a patient with failing dentition. This protocol allows for a fixed interim prosthesis with combined tooth and mucosa or implant support during the entire rehabilitation process, thus avoiding the use of complete dentures. The implants and prostheses were functioning successfully after 3 years of clinical service.

This clinical report describes a complete arch, implant-supported prosthesis with a zirconia framework and monolithic lithium disilicate crowns. The design of the computer-aided design/computer-aided manufacturing zirconia framework with cemented crowns with screw access is useful in facilitating retrievability and adequate fit, and may reduce the likelihood of porcelain chipping.

The presence of an oronasal fistula presents a challenge to maxillary complete denture fabrication because leakage of air from the nasal cavity through the fistula prevents the formation of an adequate border seal. Although surgical repair or dental implants are possible solutions, these options are invasive and sometimes not feasible. This clinical report illustrates an alternative prosthetic solution by integrating a small retentive component into a maxillary complete denture.

Implant surgery in the atrophic anterior mandible presents a number of anatomic challenges owing to the vascular and neurologic structures related to this region. Flapless implant surgery is known to be a conservative surgical approach that has a number of advantages and disadvantages for both the clinician and the patient. This clinical report describes the use of flapless implant surgery for a 2-implant overdenture in an 89-year-old patient with a severely atrophic mandible and significant anatomic constraints. The insertion of the sublingual artery into the lingual cortex close to the level of the crest of the ridge and the presence of the mental foramen at the ridge crest precluded conventional flap surgery. To overcome these anatomic challenges, a conventional surgical guide was used with careful preoperative treatment planning for a successful flapless implant surgery and subsequent overdenture therapy. The anatomic challenges, surgical and prosthetic treatment planning, choice of simple versus complex interventions, and indications and contraindications of flapless surgery are discussed.