Definitive Prosthesis Research Articles

Prosthodontic management of monostotic fibrous dysplasia of the maxilla – A case report

Prosthetic rehabilitation of patients with acquired defects of the maxilla presents a challenging task for a prosthodontist. These goals are achieved by early diagnosis, definitive interdisciplinary management, and restoration of the defect with a definitive prosthesis. This case report describes the complete prosthodontic rehabilitation of a rare case of monostotic fibrous dysplasia of the right maxilla in a middle-aged woman.

Digital acoustic analysis of the first three formant frequencies in patients with a prosthesis after maxillectomy

Statement of problemProsthetic rehabilitation with an obturator can help to restore or improve the intelligibility of speech in patients after maxillectomy. The frequency of formants 1 and 2 as well as their ranges were initially reported in patients with maxillary defects in 2002, and the evaluation method that was used is now applied in clinical evaluation. However, the details of formant 3 are not known and warrant investigation because, according to speech science, formant 3 is related to the pharyngeal volume. Clarifying the formant frequency values of formant 3 in patients after maxillectomy would enable prosthodontists to refer to these data when planning treatment and when assessing the outcome of an obturator. PurposeThe purpose of this clinical study was to determine the acoustic characteristics of formant 3, together with those of formants 1 and 2, by using a digital acoustic analysis during maxillofacial prosthetic treatment. The utility of determining formant 3 in the evaluation of speech in patients after maxillectomy was also evaluated. Material and methodsTwenty-six male participants after a maxillectomy (mean age, 63 years; range, 20 to 93 years) were included, and the 5 Japanese vowels /a/, /e/, /i/, /o/, and /u/ produced with and without a definitive obturator prosthesis were recorded. The frequencies of the 3 formants were determined, and their ranges were calculated by using a speech analysis system (Computerized Speech Lab CSL 4400). The Wilcoxon signed rank test was used to compare the formants between the 2 use conditions (α=0.05). ResultsSignificant differences were found in the frequencies and ranges of all 3 formants between the use conditions. The ranges of all 3 formants produced with the prosthesis were significantly greater than those produced without it. ConclusionsBased on the findings, both the first 2 formants and the third formant were changed by wearing an obturator prosthesis. Because formant 3 is related to the volume of the pharynx, evaluation of this formant and its range can reflect the effectiveness of the prosthesis to seal the oronasal communication and help reduce hypernasality, suggesting the utility of formant 3 analysis in prosthodontic rehabilitation.

Polyetheretherketone computer-aided design and computer-aided manufacturing framework for All-on-Four mandibular full-arch prosthesis: 3 Years' retrospective study of peri-implant soft tissue changes and ridge base relationship.

This study was conducted to evaluate the clinical peri-implant soft tissue changes during the first year after occlusal loading and the ridge base relation after 3 years for mandibular computer-aided design and computer-aided manufacturing (CAD-CAM) screw-retained implant-supported hybrid prosthesis of polyetheretherketone (PEEK) framework utilized with All-on-Four treatment concept. Sixteen completely edentulous patients were rehabilitated by four implants following the All-on-Four protocol. After 3 months, the definitive prosthesis was constructed to be a screw-retained CAD-CAM milled framework from the modified PEEK (BioHPP), bonded to polymethylmethacrylate teeth and a pink shaded indirect light-polymerized nanofilled composite resin imitating the soft tissues. Peri-implant soft tissue changes regarding plaque, bleeding, gingival scores, and probing depth were evaluated at prosthesis insertion (T0), 6 months (T1), and 12 months (T2) after insertion. Also, monitoring of the ridge base relation was performed using cone beam computed tomography at time of insertion (T0), and 1 year (T1), 2 years (T2), and 3 years (T3) after mandibular fixed detachable All-on-Four framework insertion. Using Shapiro-Wilk tests using SPSS® software version 22 (SPSS Inc., Chicago, IL), all clinical data were nonparametric, while the ridge base relation data were parametric. There were statistically significant differences regarding a plaque, gingival, and bleeding scores for all implants with the advancement of time. However, there was a statistically insignificant difference regarding probing depth in the posterior implants (p = 0.581). Regarding ridge base relation, there was a significant difference between observation times only in the anterior ridge area in between the two anterior implants (p = 0.011). Within the limitations of the study, the full-arch PEEK framework of fixed-detachable, hybrid prosthesis used with the All-on-Four concept for rehabilitation of mandibular edentulous arches is an acceptable treatment approach. Based on the stable ridge base relation posteriorly found in this study, less stress is distributed to the underlining bone due to the shock-absorbing ability of PEEK. Special considerations for frequent soft tissue follow-up and regular maintenance of oral hygiene measures are recommended.

Estimating Ni, Cr, Co, and Mo release from 3 dental casting alloys in saliva and blood at 6 and 12 months by using inductively coupled plasma mass spectroscopy

Statement of problemThe leaching of elements from long-term definitive prostheses, with saliva acting as an electrolyte, poses a biological concern. The approximate concentration in the biological samples that are considered clinically toxic ranges from 1 to 5000 nmol/L for Cr and Co, 1 to 200 nmol/L for Ni, and 1 to 20 nmol/L for Mo. While in vitro studies are available regarding the leaching of elements in artificial saliva, solutions containing protein, solutions of different pH, and different culture media, the in vivo effects of leaching in the biological sample with increasing time are unknown. PurposeThe purpose of this clinical study was to quantify the Ni, Co, Cr, and Mo metals in saliva and blood before and after restoration with prostheses made from 3 different brands of dental casting alloy at 6 and 12 months. Material and methodsThree popular brands of Ni-Cr alloy with different compositions were evaluated. A total of 150 participants requiring a definitive prosthesis were enrolled and divided into 3 groups (n=50). Heavy metal levels from saliva and blood were measured by using the inductively coupled plasma mass spectroscopy method before cementation of the prosthesis and after 6 and 12 months. ResultsThe presence of Ni in saliva was in the range of 10.34 to 12.12 μg/L, Cr was 1.04 to 1.22 μg/L, and Mo was 1.04 to 1.08 μg/L over a period of 6 and 12 months after cementation of the metal prosthesis. The presence of Ni in blood was in the range of 6.35 to 14.45 μg/L and that of Cr was 9.09 to 16.16 μg/L over a period of 6 and 12 months after cementation. Co levels were not detected from any brands in saliva or blood, and Mo was detected only in the saliva samples. ConclusionsIncreased levels of Ni and Cr in saliva and blood from all 3 brands of base metal alloy at 6 and 12 months were observed at higher than threshold values.

Immediate loaded fixed complete dentures supported by implants in patients with a history of periodontitis: A retrospective cohort study of 2 to 7 years

Statement of problemThe outcome of implant-supported fixed complete dentures in edentulous patients with a history of periodontitis is unclear. PurposeThe purpose of this retrospective clinical study was to assess the clinical outcomes of immediate loaded fixed complete dentures in individuals with a history of periodontitis and to analyze risk factors related to implant failure. Material and methodsA total of 642 implants (146 prostheses) in 119 patients were included. The follow-up period ranged from 2 to 7 years. Implant survival rates, marginal bone loss, mechanical complications, biologic complications, and patient satisfaction were evaluated. The Pearson chi-square test, independent samples t test, and multivariate generalized estimating equation were performed for statistical analysis (α=.05). ResultsEleven implants in 9 patients failed, leading to overall survival rates of 98.3% at the implant level and 92.4% at the patient level. The mean ±standard deviation marginal bone loss was 0.62 ±0.86 mm, and marginal bone loss did not differ significantly between axial and tilted implants (P>.05). Mechanical complications were detected in 55 (37.7%) definitive prostheses; biologic complications were detected in 318 (49.5%) implants. Smokers had a significantly lower survival rate than nonsmokers (odds ratio: 6.880, P=.013). Bruxers had a significantly higher incidence of mechanical complications than nonbruxers (P<.001). ConclusionsThe immediate loaded fixed complete denture supported by implants is a suitable treatment option for edentulous patients with a history of periodontitis, with high survival implant rates. Smoking is a risk factor for implant failure. Bruxism may increase the incidence of mechanical complications with implant-supported fixed complete dentures, and the overall biologic complication incidence is comparatively high.

IN SITU ORAL MELANOMA: DIAGNOSIS, TREATMENT, AND FOLLOW-UP

Oral melanoma is an aggressive cancer in which the cells display melanocytic differentiation. In situ oral melanoma is considered an extremely rare tumor and the prognosis is poor compared to its cutaneous counterpart. A 67-year-old woman was referred for evaluation of a lesion on the maxillary alveolar mucosa. Intraoral examination revealed a nondetachable black patch on the maxillary alveolar mucosa extending to the hard palate with irregular borders and well-defined limits measuring 3 × 1.5 cm. A biopsy was performed, and microscopic analysis showed moderate atypical junctional melanocytic. Immunohistochemical analysis was positive for S-100, melan-A, and melanosome. The definitive diagnosis was in situ oral melanoma and the patient was treated surgically with partial maxillectomy. A definitive obturator prosthesis was made to provide effective rehabilitation. A 15-month follow-up showed no evidence of recurrence or metastasis. Oral melanoma is an aggressive cancer in which the cells display melanocytic differentiation. In situ oral melanoma is considered an extremely rare tumor and the prognosis is poor compared to its cutaneous counterpart. A 67-year-old woman was referred for evaluation of a lesion on the maxillary alveolar mucosa. Intraoral examination revealed a nondetachable black patch on the maxillary alveolar mucosa extending to the hard palate with irregular borders and well-defined limits measuring 3 × 1.5 cm. A biopsy was performed, and microscopic analysis showed moderate atypical junctional melanocytic. Immunohistochemical analysis was positive for S-100, melan-A, and melanosome. The definitive diagnosis was in situ oral melanoma and the patient was treated surgically with partial maxillectomy. A definitive obturator prosthesis was made to provide effective rehabilitation. A 15-month follow-up showed no evidence of recurrence or metastasis.

Surgical guides for flapless dental implant placement and immediate definitive prosthesis installation by using selective laser melting and sintering for 3D metal and polymer printing: A clinical report

Integration between the phases of computer-based guided dental implant surgery can be used to optimize oral rehabilitation. Two new surgical guides prepared by using the 3D metal and polymer printing technology are presented for immediate implant loading and definitive fixed prosthesis construction in flapless dental implant surgery. Nine implants and 2 fixed prostheses were installed in 2 completely edentulous adult patients by using a metallopolymer surgical guide with a metal central bar attached to a polymer seal or a metal guide. Virtual planning was used to design the 3D printed surgical guides, which were then constructed by using selective laser sintering (SLM) and selective laser melting (SLS). The 3D printed surgical guides oriented the surgical placement of the implants and were welded to the abutments and attached to the denture framework. The technique allowed implants and prostheses to be installed on the same day.

Influence of geometric dimensions on early failures of adhesively retained composite resin core build-ups.

To determine the influence of the geometric dimensions of core build-ups on early core build-up failure, that is, loss before definitive prosthesis cementation. Adhesive core build-ups of exclusively vital teeth in 114 participants were evaluated (n materials: 40 Rebilda DC, 38 Multicore Flow, 36 Clearfil DC Core; n teeth: 8 incisors, 54 premolars, 52 molars). Impressions of the abutment teeth were made (1) after removal of insufficient restorations/caries and (2) after core build-up and preparation for a fixed prosthesis. Digitized model surfaces of both situations were aligned (Geomagic Design X) and core build-up volume (VCBU ), remaining hard tissue volume (VAbut ), and size of the adhesive surface (Aadh ) were assessed. The derived measure dCBU =VCBU /Aadh can be interpreted as mean arithmetic core build-up thickness. Associations between participant or core build-up design characteristics and the occurrence of early failures were statistically evaluated (SPSS v27, α=0.05). A total of six (5.3%) core build-up failures were registered. Higher participant age, greater core build-up volume VCBU and greater arithmetic uniform thickness dCBU were associated with a greater incidence of failure in bivariate and univariate, however, not in multivariate statistics. Core build-up volume and thickness were associated with early success or failure. In the case of voluminous/thick core build-ups in relation to the adhesive surface, additional measures, such as the preparation of retentive elements to increase the bonding area, might be considered to reduce the risk of early core build-up failure.

Deep tissue injury as possible pathogenesis of acute inflammatory swelling or cellulitis after connecting implant super-structures: a case series study

Background: Acute swelling or cellulitis may develop within a few days after placing a definitive prosthesis or reconnecting a loose healing abutment/prosthesis, though its cause remains unclear. In this study, we propose a mechanism for the underlying pathogenesis. Methods: We retrospectively reviewed the symptoms and signs, onset of symptoms, recovery duration, and laboratory data of seven women and two men (55–84 years) who exhibited acute swelling and pain around dental implants within a month of connecting definitive prosthesis or reconnecting a loose healing abutment/prosthesis between 2013 and 2021. Results: The extent of the swelling varied from the gingiva and vestibule around the implant to the face and neck regions. The swelling persisted despite removal of the connected superstructure. All patients recovered within three weeks of symptom onset. Conclusions: Our findings suggest that the rapid onset of symptoms and signs, progress, duration, and etiology were consistent with the pathogenesis of deep tissue injury, which is characterized by acute inflammatory swelling that initiates from the interface between bone and subcutaneous tissue and progresses outward. Clinicians should be aware of the pathogenesis of pressure-induced injury and provide adequate treatment based on the underlying physiological process.

Evaluation of Immediately Loaded Parallel Conical Connection Implants with Platform Switch in the Maxillary Esthetic Zone: A Prospective Clinical Study

To assess immediately loaded parallel conical connection (Nobel Biocare) implants with platform switch design in the maxillary esthetic zone for soft and hard tissue changes. A total of 20 patients (n = 20) underwent prosthetic replacement of the missing maxillary anterior tooth, with an immediately loaded parallel conical connection implant (Noble Biocare, Sweden) having a platform switch design. The size of the implant was 3.75 mm in width and 13 mm in length for all patients and placement followed a standardized surgical protocol. Postoperatively, acrylic provisionalization was done within 48 hours followed by a definitive zirconia prosthesis in the 3rd month. Clinically and radiographically, the implants were evaluated for hard tissue (bone density, implant stability, crestal bone loss) and soft tissue changes (mucosal thickness-MT, sulcus probing depth-PD, bleeding on probing-BOP, width of keratinized gingiva-KG) at baseline till 36 months with follow-up intervals after loading. All patients showed uneventful healing. The difference in implant stability and density scores was significant (p <0.05*) from baseline to 36 months indicating bone formation and osseointegration of the implant. Bleeding on probing was not observed, and probing depth remained within the acceptable range (≤5 mm) at all time intervals after loading. The marginal bone loss was minimal (≤0.2 mm annually) with the absence of implant mobility and without any peri-implant radiolucency. The thickness of the gingiva (3.47 ± 0.34 mm) and width of keratinized gingiva (2.46 ± 0.39 mm) remained within reasonable limits at the 36th month with acceptable esthetic appearance. In the present study, immediate loading of Nobel parallel conical connection implant in the maxillary anterior region provided adequate primary stability, minimal marginal bone loss, and increased bone density indicating earlier osseointegration. Decreased probing depth, absence of bleeding on probing, and adequate tissue collar at the neck showed better soft tissue emergence in the esthetic zone. The platform switch design demonstrated promising results and therefore can be used as an alternative to the conventional method. The present study results suggest that parallel conical connection implants (Nobel Biocare) with TiUnite surface, built-in platform switch combined with conical connection interface, parallel walled body, tapered apex, and double threads from tip to platform are all designed to provide high primary stability and support immediate function protocol, hence can be used flexibly in different bone densities.

Digital workflow for definitive immediately loaded complete arch CAD-CAM implant-supported prosthesis in 3 appointments without using intraoral scanning

This article presents a rapid technique for the accurate transfer of implant positions immediately after image-guided surgery to enable the immediate installation of a definitive complete arch implant-supported prosthesis with an implant biological width of 3 mm within 3 appointments. A sleeveless copy of the implant surgical guide is magnetically connected to a reference guide to ensure the accurate capture of cylindrical titanium transfer abutments. In the laboratory, the sleeveless guide with the splinted transfer abutments attached is used to generate a definitive cast to be scanned with a desktop scanner. The resulting digital definitive cast is then combined with the original meshes of the prosthetically driven virtual treatment plan to enable a definitive computer-aided design and computer-aided manufactured prosthesis to be fabricated and installed with passive fit.

A technical and clinical digital approach to the altered cast technique with an intraoral scanner and polyvinyl siloxane impression material

This technique digitalizes the clinical and laboratory steps of fabricating removable partial dentures (RPDs) with the altered cast technique. An intraoral scanner was used to capture the mandibular Kennedy class II partially edentulous arch. An RPD framework was fabricated digitally and then combined with a custom tray with a wax occlusal rim. A conventional polyvinyl siloxane altered cast impression was made and then digitalized both intraorally and extraorally, followed by a digital interocclusal record. The resulting scan was modified to produce an additively manufactured cast. The teeth and gingival components were then designed and fabricated with a combination of additive and subtractive manufacturing, followed by the conventional acrylic resin pour technique. The definitive prosthesis was completed with minimal conventional techniques and without the use of gypsum, prefabricated teeth, or a physical articulator. The technique reduces the number of appointments and achieves the functional extension of the prosthesis through border molding, which is not possible with intraoral scanning.

Prosthetic Rehabilitation of Cancellous Osteoma – A Case Report

Osteomas are benign osteogenic lesions of the bone. When this involves the maxilla and requires resection, maxillectomy defect results and this in turn leads to compromised function in terms of mastication, speech and also psychological well-being. Definitive obturator prosthesis fabricated with maximum extension and incorporation of proper design rehabilitates the patient by improving masticatory efficiency, increasing speech clarity, improves the esthetics, thereby enhancing the overall quality of life. This case report presents one such case of a rare intraoral peripheral cancellous osteoma affecting the maxilla and its prosthetic rehabilitation following surgical resection

An implant-supported overdenture for a mandibular defect after tumor resection guided by 3-dimensional finite element analysis: A clinical report

This clinical report describes the rehabilitation of a mandibular defect after tumor resection with an implant-supported overdenture and the attachment selection as guided by 3-dimensional finite element analysis. Autologous bone grafting was declined by the patient who demanded the restoration of lateral appearance and mastication function. Three implants were placed based on the condition of the bone, and a satisfactory definitive prosthesis was provided that corresponded with the results of the finite element analysis.

Retrospective Study from a Single Center to Identify Risk Factors Associated with Reinfection in Patients Undergoing 2-Stage Revision Surgery for Periprosthetic Joint Infection.

BackgroundThis study identified risk factors associated with reinfection and created a scoring system designed for patients with periprosthetic joint infection (PJI) who have undergone prosthetic resection and spacer implantation.Material/MethodsPatients who underwent 2-stage revision for PJI from January 2010 to December 2017 were retrospectively analyzed in this study. Patients were divided into 2 groups: infection recurrence and infection cure. Demographic and clinical information, laboratory test results, and radiological images that were potentially associated with infection were obtained and analyzed.ResultsSeven independent risk (protective) factors for infection recurrence in patients with PJI who underwent 2-stage hip revision surgery were identified: C-reactive protein level, type of bacterial infection, age, immunosuppression, albumin/globulin ratio, glucose level, and magnetic resonance imaging findings. Finally, a weighted scoring system of 100-mark system was established and the area under the curve was 0.965 (95% confidential interval=0.947–0.983). The predictive scores for low risk (≤30%), moderate risk (31–69%), and high risk (≥70%) of infection recurrence were ≤45, 46–77, and ≥78, respectively.ConclusionsFor patients with PJI who had already undergone joint resection and spacer implantation, this newly established scoring system might help determine the accurate risk of infection recurrence after a definitive new prosthesis implantation. Patients with scores greater than 78 points would be considered very likely to have an infection recurrence. Therefore, the second-stage revision surgery should be changed to an additional anti-infection treatment or a debridement surgery instead of a definitive prosthesis implantation surgery.

Guided maxillary full-arch implant rehabilitation using a novel chrome cobalt alveolar bone reduction guide

Full arch rehabilitations require precision in each step of the digital workflow, from virtual planning to implant placement. In guided surgery, accurate alveolar reduction and implant 3D positioning are crucial. This study presents the use of a novel chrome cobalt reduction guide for increased predictability of the rehabilitation protocol. The treatment protocol for a 27-year-old female who presented with failing maxillary dentition is presented. After evaluation of CBCT scans, an immediate fixed implant-based prosthesis was planned. Using implant planning software, a tooth-supported guide, a chrome-cobalt alveolar reduction guide, and an implant guide stacked onto the reduction guide were fabricated. The digital denture was created virtually pre-operatively. The surgery was performed under general anesthesia based on the consecutive use of the three guides. Four Neodent implants were placed in the maxilla and splinted through a metal bar incorporated into the interim prosthesis. Installation of the definitive prosthesis took place three months after the initial surgery. The mandible was rehabilitated with ten disilicate glass crowns following a digital workflow. The surgical procedure was uneventful and healing was successful. The rigidity of the reduction guide and the extra stabilizing pins facilitated implant placement and increased precision. The optimal 3-D positioning facilitated the rehabilitation process and the patient was highly satisfied with the results. Due to the increased stability and higher fracture resistance, this novel chrome-cobalt guide can facilitate the alveolar bone reduction procedure. This leads to higher predictability and patient satisfaction.

Interdisciplinary prosthetic rehabilitation following bilateral maxillectomy with total upper lip and unilateral zygoma resection: A clinical report

This clinical report describes the design and fabrication of an implant-retained and soft-tissue-supported obturator prosthesis and a magnetic retained midfacial prosthesis for a patient with a midfacial defect following bilateral total maxillectomy, removal of the left zygoma, and excision of the entire upper lip. The patient underwent multiple head and neck surgeries for 4 separate primary oral cancers, 1 recurrence, and 1 pulmonary metastasis. The definitive obturator prosthesis was retained by 1 zygomatic implant with soft-tissue support and retention. The midfacial prosthesis was attached to the obturator prosthesis with magnets, improving appearance and the recovery of significant aspects of the patient’s speech and swallowing. Some improvement in mastication was observed.

Orthognathic correction and corticobasal implant-supported prostheses as a treatment modality for partial edentulism with mandibular prognathism: A case report and review of literature

IntroductionMandibular prognathism manifests as elongation of the mandible in the anteroposterior direction, resulting in a sunken appearance of the middle third of the face and sad look of the eyes. It adversely affects esthetics, function, and oral health, reducing the patients' self-esteem. It therefore presents a significant challenge.Presentation of caseA 23-year-old woman presented with prognathic features characterized by mandibular protrusion, maxillary retrusion, a prominent chin, and reduce self-esteem. Intraoral examination revealed multiple extracted teeth, severe fracture of the crown at 23, mobility of the fixed prosthesis on 13, 14, 15, and 16, a root stump of 18, and periodontally compromised teeth (31, 32, 33, 41, and 42).A multidisciplinary team formulated the following treatment plan: stage 1, orthognathic osteotomy to retrude the mandible at 34 and 44; stage II, fabrication of transitional acrylic partial dentures; and stage III: fabrication of definitive corticobasal implant-supported prostheses. The patient was delighted with the treatment and complied with the oral hygiene instructions and follow-up program. After 7 years of function, the patient presented without complaints and exhibited significant improvement in oral health, self-esteem, and quality of life.DiscussionThe management of mandibular prognathism requires a multidisciplinary approach. The treatment implemented was considered the optimal option that aligned with the recommendations of several researchers to reduce facial disfigurement and rehabilitate the edentulous state.ConclusionThe use of corticobasal implant-supported prostheses for the rehabilitation of patients with partial edentulism can significantly improve the treatment outcome following orthognathic surgery in cases with mandibular prognathism.

A simplified technique for fabrication of obturator using light curing wax pattern: A case report

Surgical excision of the maxilla results in communication between the oral cavity, nasal cavity and maxillary sinus. Rehabilitation of such defects involves fabrication of obturator prosthesis by the maxillofacial prosthodontist. Various techniques and materials have been used in the past for rehabilitation of such defects.To Fabricate a Obturator Prosthesis using Light Cure Wax Pattern.A 65-year-old man reported with the chief complaint of inability to chew food due to an ill-fitting prosthesis. His history revealed that patient had undergone maxillectomy of left side due to Carcinoma maxilla 03 years back, followed by the fabrication of a definitive obturator prosthesis. Intraoral examination revealed a well healed Aramany’s Class II post maxillectomy defect on the left side measuring 5 cm X 3.5 cm anteroposteriorly and mediolaterally, with everted margins and irregular borders. This clinical report describes rehabilitation of maxillectomy defect with definitive obturator prosthesis. A light cure wax pattern was used (LiWa®; Willmann &amp; Pein Gmbh) for the fabrication of metal framework.Fabrication of a cast metal framework involves a complex laboratory procedure to achieve the clinical success of the prosthesis. LiWa light curing waxes can be successfully used as an alternative to the conventional wax pattern for the fabrication of cast partial dentures framework for definitive obturators.The light cure wax pattern helped in reducing the number of laboratory steps and allowed wax pattern trial in the patient's mouth, saving precious time and ensuring a precise fit of the prosthesis.

A Retrospective Analysis of Implants with Low Insertion Torque in Immediately Loaded Full-Arch Fixed Prostheses with Corresponding Occlusal Schemes.

Poor alveolar bone quality and quantity may cause low insertion torque during implant placement; therefore, a delicate occlusal design is important for the immediate loading procedure. This retrospective clinical study aimed to investigate (1) the proportion of implants with a low insertion torque between the maxilla and mandible, (2) factors affecting implants with a low insertion torque, and (3) survival rates of implants with a low insertion torque value (< 35 Ncm) using different occlusal designs with full-arch fixed prostheses supported by immediately loaded implants. Between 2013 and 2017, patients who received full-arch reconstructions were treated with immediately loaded one-piece fixed prostheses supported by four to six implants. Full-arch fixed prostheses with at least one immediately loaded regular implant with a low insertion torque value were included in this study. The fixed provisional acrylic prosthesis with a rigid framework was delivered within 3 to 5 days after surgery. According to the distribution of implants with low insertion torque, provisional prostheses were divided into three groups with different occlusal schemes. Definitive prostheses were fabricated after 3 months of loading. A total of 144 patients were treated; 608 and 304 regular implants were inserted in 118 maxillae and 76 mandibles, respectively. Moreover, 42 patients (11 men and 31 women) with 39 maxillae and 4 mandibles were included in this study. The proportion of implants with low insertion torque values in the maxilla was significantly greater than that in the mandible (10.5% vs 1.6%, respectively, P < .001). Implant length and low insertion torque value had no significant correlation (P = .948). Implants with a 3.3-mm diameter (narrow platform) had a greater proportion of low insertion torque values than 4-mm-wide implants (P = .002). Implants placed in a fresh socket had a greater proportion of insertion torque values ≥ 35 Ncm (P = .023). The overall cumulative implant survival rate was 98.6%. Groups 1, 2, and 3 had 14, 23, and 6 provisional prostheses, respectively. The survival rates for implants with insertion torque values < 35 Ncm and ≥ 35 Ncm were 98.4% and 98.7%, respectively, and were not significantly different (P = .866). All prostheses were still functioning during the mean follow-up of 3.7 ± 1.2 years. The high cumulative implant survival rate indicated that implants with a low insertion torque in immediately loaded full-arch provisional prostheses did not jeopardize the outcomes after a corresponding occlusal scheme was used.