Interarch Distance Research Articles

Photogrammetry protocol in babies with congenital torticollis: part 1 – inter-arch intraoral assessment

Torticollis is defined as an imbalance of the sternocleidomastoid muscle (SCM), with less extension of the neck, resulting in a preference to turn the head more from one side to the other. The characteristics frequently found are: ear contralateral to the torticollis displaced forward, facial asymmetry, and contralateral occipital flattening, as well as a smaller ipsilateral eye, causing misalignment of the eyes. This condition can also cause mandibular inclination (MI), in the frontal plane, with a difference in opening between the maxilla and mandible from one side or the other. The diagnosis and treatment of torticollis are routinely carried out by the physiotherapist and the diagnosis of this mandibular inclination is traditionally through visual examination. This assessment of mandibular inclination, carried out by the dentist, in an objective manner, can contribute to the diagnosis and also to the monitoring of proposed treatments that should reduce mandibular asymmetries. The objective of this study was to create a protocol for objective measurement of the distance between the maxilla and mandible, on the right and left sides, using photogrammetry, to detect whether mandibular inclination can be observed by the shorter inter-arch distance on the side corresponding to the torticollis. Case reports of two babies (1 baby aged 9 months and another aged 1 year and 1 month), diagnosed with congenital torticollis. Photogrammetry was carried out: the babies were positioned on a dental stretcher and photographed in maximum opening, intermediate, and closing positions. Using the photos and the IMAGE J program, measurements between the maxilla and mandible were taken (see photogrammetry description). Results: The measurement protocol used in both babies confirmed the greater mandibular inclination by approaching the hemi-arch corresponding to the side of the torticollis, compared to the opposite side. Objective measurement of mandibular inclination can be part of the timely diagnosis for congenital torticollis. Studies with an adequate sample size and methodology are necessary to confirm this diagnostic tool.

Effect of Different Intraoral Scanners on the Accuracy of Bite Registration in Edentulous Maxillary and Mandibular Arches

ObjectivesThe objective of this study was to use in vitro models to examine the bite registration accuracy of four different intraoral scanners (IOS) for edentulous maxillary and mandibular arches. The objective was to assess the trueness and precision of the IOS and determine if there were significant differences between them. MethodsAn Asiga Max UV 3D printer was used to print maxillary and mandibular edentulous models based on the shape of Frasaco models (artificial dental arch models). Four dental implants were placed symmetrically in both models using Straumann BLT RC implants. Digital impressions were taken with Primescan, Trios 3, Trios 4, and Medit i500 intraoral scanners (n = 10 for each IOS). Digital bite registrations were made, and scanning data was exported in STL format. The accuracy of the interarch distance (the distance between the metrological spheres attached to the mandibular and maxillary models) was estimated for each IOS. ResultsThe results showed significant differences in trueness and precision between different IOS (p <.05), except Medit i500 and Trios 3 (p >.05). Primescan provided the most accurate results, followed by Medit i500, Trios 3, and Trios 4, respectively. Conclusionswithin the limitations of this study, the IOS type affects the accuracy of interocclusal bite registration in in vitro design. Only Primescan achieved clinically acceptable accuracy for the interocclusal recording of edentulous arches. Clinical RelevanceThe comparison of the accuracy of bite registration between different intraoral scanners will help increase the efficiency of the clinical application of digitalized interarch registration.

Advances in Surgical Template Design in Dental Implantology

Background: Expansion of three-dimensional (3D) printing technology and improvements in planning software have led to increased accuracy and precision in dental implant positioning and new applications for surgical templates in implantology. The objective of this report is to demonstrate the application of locally printed surgical templates in various dental implant surgeries and site development procedures. Methods: Nine patients were referred to the Department of Periodontics, Army Postgraduate Dental School, Postgraduate Dental College, Fort Eisenhower, GA, USA, for replacement of missing or hopeless teeth using dental implants. All surgeries were planned virtually and completed using customized surgical templates produced within the local facility. The presented cases demonstrate use of surgical templates to simplify surgery across a wide spectrum of clinical scenarios—placement of multiple adjacent implants, immediate implant placement, immediate provisionalization, sinus elevation in dentate and edentulous patients, removal of a retained root fragment in conjunction with implant surgery, alveoloplasty to increase interarch distance, and fully guided implant surgery. Results: In the presented dental implant surgeries, use of locally produced surgical templates permitted transfer of the planned implant positions to the patients with high reliability. Use of surgical templates in sinus elevation procedures ensured augmentation in the appropriate positions and simplified intraoperative management of complex anatomy. Conclusions: Specialized surgical templates have the potential to reduce the duration of surgery, limit patient morbidity, enhance communication among clinicians, and simplify the restorative phase of therapy. Accessibility to new technology has allowed implant surgeons to move beyond the era of accurate implant placement into a period characterized by creative solutions to clinical problems.

Digital mounting accuracy of 2 intraoral scanners with a single anterior or bilateral posterior occlusal scan: A three-dimensional analysis

Although intraoral scanners (IOSs) are popular, few studies have evaluated the accuracy of digital mounting by using IOSs. The purpose of this in vitro study was to compare the accuracy of digital mounting by using 2 IOSs and 2 occlusal scanning methods. Fourteen Ø5-mm zirconia balls were attached approximately 5 mm apical to the free gingival margin of both second molars, second premolars, and canines and between the central incisors in maxillary and mandibular epoxy casts. A polyetheretherketone hexagonal cube with a 10-mm-long edge was attached to the buccal side of the missing mandibular right first molar area, and the cube was used to set a part coordinate system. Two IOSs (TRIOS 3, Primescan) were used to assess the intra-arch and interarch accuracies. For intra-arch assessment, each IOS was used to digitally scan the mandibular epoxy cast 15 times and fabricate 15 datasets. The deviation of each zirconia ball centroid was statistically compared between the IOSs. For interarch assessment, each IOS was used to digitally scan the maxillary and mandibular epoxy casts, and the data were digitally mounted by using a single anterior occlusal scan (A) or bilateral posterior occlusal scan (P). Both occlusal scans were performed 15 times; therefore, 4 groups (15 datasets per group) of mounted digital datasets were assigned. The deviation of each maxillary zirconia ball centroid, as well as the interarch distance between the corresponding maxillary and mandibular zirconia ball centroids, were compared among the 4 groups. For statistical analysis, the Mann-Whitney U test and Kruskal-Wallis test with Bonferroni correction were used (α=.05). Primescan had less deviation than TRIOS 3 in the complete arch scan. When the zirconia balls were close to the origin, the bilateral posterior occlusal scan produced less deviation of their centroids. Primescan produced decreased interarch distance in the anterior and posterior dentition, while TRIOS 3 produced increased interarch distance in the anterior dentition and decreased interarch distance in the posterior dentition. A significant difference was noted in intra-arch accuracy between the IOSs, and the difference influenced the digital mounting accuracy. The type of occlusal scan and IOS significantly influenced the accuracy of digital mounting. Both IOSs produced decreased interarch distances in the second molar area.

Hollow Denture for Completely Edentulous Maxillary Resorbed Ridges- A Case Report

Basically, complete denture success relies on the factors like stability, retention, function, support and esthetics. Mostly severely resorbed maxillary ridges are constricted and narrow and the inter-arch distance is increased due to which there is a decreased stability, support and retention. In this case the weight of the complete dentures compromises the factors further. This case report depicts a simplified technique for fabricating the lightweight hollow complete denture for balancing the factors influencing the denture and also preserves the supporting tissues and bone

Attachment Retained Tooth Supported Overdentures: A Case Series

Present case series describes the three different types of attachments use for tooth supported overdenture for prosthetic rehabilitation. Loss of teeth causes continuous resorption of the bone leading to a compromised treatment. Retaining two or more natural teeth can be used as an abutment for prosthetic rehabilitation of partial edentulism arches. Preventive prosthodontics includes tooth supported overdentures which preserves natural teeth, roots and maintains propioception. Depending upon the interarch distance available various types of attachments can be used to enhance the retentive factors. The first case (71-year-old female patient) describes the use of telescopic attachment overdenture on 33, 43 with available interarch space of 15 mm in mandibular arch. The second case (62-year-old female patient) describes the use of ball attachments overdenture on 34 and 35 with available interarch space of 13 mm in mandibular arch. The third case (60-year-old female patient) is about equator attachment overdenture on 33, 43 with available interarch space of 12 mm in mandibular arch. Use of telescopic, ball and equator attachments for tooth supported overdentures has enhanced the retention, stability, function and aesthetic outcome of the removable prosthesis in mandibular arch. The natural teeth provide additional support, stability and retention of the overdenture than the edentulous ridges alone which is particularly advantageous for mandibular arch.

Treatment planning and key points in clinical procedure of implant overdenture for edentulous patients

Many randomized controlled clinical trials have reported that implant overdentures provided edentulous people with better retention, stability, and masticatory performance than conventional complete dentures did. The design of implant overdentures for edentulous jaws should be based on comprehensive consideration of factors such as anatomic structure, alveolar bone resorption, inter-arch distance, choice of implant number/distribution and suprastructure. During the clinical procedure, timing of attachment connection, choice of impression technique, methods of maxilla-mandibular relationship registration, wax-up try-in, and prostheses delivery should be determined according to the type of implant overdentures. The appropriate choices and conduction of the above-mentioned procedures can guarantee the long-term success of the prostheses. This review elaborates on the clinical significance, treatment design, key steps in clinical procedure of implant overdenture, and summarizes follow-up and maintenance following denture delivery.

Interarch distance is a target restorative space value: clinical decisionmaking of implant restoration guided by measured value

When design an implant restoration for edentulous patients, many doctors ignore the sufficiency of the interarch distance (vertical distance) or horizontal distance of the patient to accommodate the superstructure and restoration before designing the implant plan. However, the connotation of measuring the interarch distance or horizontal distance has not been clarified in clinical practice. It is often based on visual estimation after operation, and the decision-making path of implant restoration is inverted, resulting in many mistakes regarding the restoration after implantation. The main reason is the lack of standardized paths and practical methods to use before surgery. This article recommended initially establishing a maxillo-mandibular relationship based on natural teeth, old dentures, or new ones and then using the height and horizontal distance or angle of the target restorative space, which was easier to grasp as the measured index. The minimum vertical distance (including the height of the gingival surface and the bone surface) and the horizontal distance (or the angle from the bone or gingival surface to the proposed occlusal plane) should be measured before operation. A decision tree of edentulous jaw restoration guided by the values of the repair space was established based on the measured values. This article clarified the measuring points and planes and thus provided a quantitative relationship basis for the design of implant restoration.

Management of a partially edentulous patient with idiopathic root resorption by using digital and conventional implant planning technologies

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.

The use of implant assisted removable partial denture in a partially edentulous patient with a few unilateral remaining teeth and reduced interarch distance: A case report

Implant-assisted removable partial dentures (IARPD) provide additional retention and stability by placing a small number of implants in the strategic positions. Since the two implants can be covered by National Health Insurance Services, the treatment modality using IARPD has been increased to restore partially edentulous patients with a few unilateral remaining teeth and improved the clinical effectiveness and patient satisfaction. The patient with two anterior unilateral remaining teeth showed a problem of frequent fracture of artificial teeth and denture base with maxillary Kennedy Class I RPD due to wear of mandibular anterior teeth and loss of occlusal vertical dimension. This case report suggested that the incorporation of a limited number of implants into IARPD could improve the function and patient satisfaction for the partially edentulous patients.

The influence of prosthetic crown height and implant-abutment connection design selection on the long-term implant-abutment stability: A laboratory study

Background and aimLong-term edentulism associated with vertical loss of alveolar bone might lead to increased suprastructure height. This study aimed to evaluate the effect of suprastructure height on the stability of the implant-abutment connection by investigating the stability of two different two-piece titanium implants with internal hexagonal or conical connections under simulated oral loading conditions. Materials and methodsA total of 48 specimens were used. The specimens were divided into 2 groups according to their implant-abutment connection (group H: internal hex connection, group C: conical connection). Each group was further divided into 3 groups according to the applied suprastructure height (H1; C1: 10 mm, H2; C2: 14 mm and H3; C3: 18 mm) (n = 8). All specimens were subjected to a cyclic loading force of 98 N for 5 million simulated chewing cycles. Then, all implants that survived the chewing simulation were quasi-statically loaded until failure. The monotonic-failure load and monotonic-bending moment at failure were evaluated. ResultsAfter the dynamic chewing loading, the implants showed the following survival rates: group H: 95.8%; group C: 100%. The implant suprastructures revealed survival rates of 100% and 91.5% for groups H and C, respectively. After the artificial chewing simulation of 5 million cycles, some implants in the groups with higher crowns (14 mm and 18 mm) showed crack formation and plastic deformations under the light microscope. Regarding monotonic-failure load, implants with shorter suprastructures (10 mm) revealed higher resistance to failure (C1: 1496 and H1: 1201 N) than longer suprastructures (18 mm) (C3: 465 and H3: 585 N) which was expected. The mean monotonic-bending moment values at failure ranged from 400.7 Ncm to 673.3 Ncm. ConclusionImplant-supported restorations with increased crown height are considered stable for an extended time period (5 million cycles which equals approximately 20 years clinical service) and a reliable treatment option in case of increased inter-arch distance. There was no difference in stability of the two internal connections. Nevertheless, the integrity of implant components might be impaired when crowns with increased heights are applied.

Rehabilitation of edentulous maxillary arch with hollow denture in an elderly patient with bell's palsy

Retention and stability are the main objectives in a complete denture fabrication. The weight of a maxillary complete denture is one of the factors that affects its retention and stability. Excessive interarch distance between the maxillary and mandibular edentulous arches increases the height and weight of the prosthesis, thus compromising the retention. Long lip length further compromises the situation. This article describes a case report of prosthetic rehabilitation of a patient with bilateral gross asymmetry due to unilateral Bell's palsy and increased prosthetic space by fabricating a light-weighted hollow denture to improve the esthetics and function.

Computer-engineered complete denture fabrication with conventional clinical steps: A technique to overcome protocol limitations

Treating patients with complete edentulism presents unique clinical challenges. With advancements in digital dentistry and computer-engineered complete denture fabrication, new clinical challenges occur. This report describes a modification to a computer-engineered complete denture maxillomandibular relation–recording protocol to manage a patient with an increased interarch distance.

Validity and reliability of intraoral conventional tracer and intraoral digital tracer in different positions for recording horizontal jaw relation in edentulous patients.

Aim:The purpose of the study is to evaluate and compare the horizontal mandibular positions recorded between intraoral conventional tracer and intraoral digital tracer in upright and supine position.Materials and Methods:Twenty-four edentulous patients with well-formed ridge and adequate interarch distance space were selected. MATLAB software was assimilated with intraoral digital tracer and was utilized in the study for recording the horizontal movements of the mandible, i.e., gothic arch tracing by intraoral digital tracer and was observed on a laptop with the help of MATLAB Software. For each subject, multiple mandibular readings were recorded and analyzed through software, and similar readings were recorded with conventional intraoral tracers. The comparison between intraoral conventional tracer and intraoral digital tracer was done to assess the reliability. Moreover, the consistency of recording horizontal mandibular position was also compared between upright and supine position.Results:The data were procured and utilized in comparison for different positions revealed statistically significant difference by using Student's Paired t-test. The test resulted in supine position better compared to upright position (P = 0.0001). The association between supine position with upright position was calculated using Fischer's exact test, and it was also found to be statistically significant (P = 0.002). The Pearson's Correlation analysis was performed to check the agreement between upright and supine position and very weak downhill correlation (r2= −0.130) was observed between the two variables.Conclusion:On evaluation and comparison of horizontal mandibular position, it was found that the intraoral digital tracing technique is more valid compared to conventional intraoral tracer technique. It was also observed that the consistency of reproducibility in recording horizontal mandibular position in supine position is significantly higher than upright position.

Trueness and Precision of Three-Dimensional Digitizing Intraoral Devices.

Aim To measure the trueness and precision under repeatable conditions for different intraoral scanners (IOSs) when scanning fully edentulous arch with multiple implants. Materials and Methods Three IOSs and one industrial scanner were used to scan one edentulous master cast containing five implant scan bodies and three spheres. The cast was scanned thirty times with each scanner device. All scans were analyzed in the inspect software, and three-dimensional locations of the implants and the interarch distance between the spheres were measured. The values were compared to measurements made with one coordinate measuring machine (true value). One-way ANOVA was used to calculate the differences between IOSs and in comparison with the true value. Results Significant differences were found between all IOSs. For the implant measurements, Trios 3 had the lowest trueness (≤114 μm), followed by Trios 3 mono (≤63 μm) and Itero element (≤−41 μm). Trios had the lowest precision (≤135 μm), followed by Itero element (≤101 μm) and Trios 3 mono (≤100 μm). With regard to the interarch distance measurements, Trios 3 had the lowest trueness (≤68 μm), followed by Trios 3 mono (≤45 μm) and Itero element (≤40 μm). Trios 3 had the lowest precision (≤206 μm), followed by Itero element (≤124 μm) and Trios 3 mono (≤111 μm). Conclusion The results from this in vitro study suggest that precision is low for the tested IOS devices when scanning fully edentulous arches with multiple implants.

A Case History Report on Use of Orthodontic Intrusion in a Partially Edentulous Patient

This case history report highlights the possibilities and limitations of orthodontic molar intrusion using temporary anchorage devices (TADs) in the prosthodontic management of patients with compromised interarch distance.

The Hollow Maxillary Complete Denture: A Simple, Precise, Single-Flask Technique Using a Caramel Spacer.

The success of removable prostheses ultimately depends on a number of factors such as retention, stability, support, esthetics, and masticatory function. Increased intraoral inter-arch distance leads to an increase in the weight of the prosthesis. This may compromise the retention and resistance, which are key for a successful removable prosthesis. Various methods, techniques, and materials have been reported to minimize the weight of a prosthesis. This article describes a simple, unique, precise single-flask technique for the fabrication of a lightweight maxillary prosthesis using caramel as a 3D spacer, which was "indexed" to obtain a uniform thickness of acrylic around the hollow cavity.

Prosthodontic treatment of a retrognathic edentulous maxilla demonstrating limited interarch distance: 3.5-year results with fixed and removable implant prostheses

The prosthodontic treatment of patients with a retrognathic edentulous maxilla should consider the restoration of the lower facial profile and access for oral hygiene. This clinical report describes prosthodontic treatments of a patient with edentulism who presented with repeated fractures of the denture teeth of a maxillary implant-supported complete fixed dental prosthesis (ICFDP) and a mandibular implant-supported overdenture. Considerable plaque accumulation was noted on the ICFDP, which was replaced with an open palatal design implant-supported overdenture. However, the patient experienced difficulty managing the 2 removable prostheses. The patient’s mandible was eventually restored with a milled titanium alloy framework ICFDP with metal occlusal surfaces. This combined approach of fixed and removable prostheses was stable at 3.5-year follow-up appointment, without compromising the patient’s oral hygiene or comfort.

Clinical Considerations while increasing Occlusal Vertical Dimension

ABSTRACTA decrease in occlusal vertical dimension (OVD) may result from tooth structure loss and extraction of posterior teeth, and it affects the esthetics, function, comfort, and lower facial height (LFH). Rehabilitation of patients with worn dentitions may require increase in OVD and interarch distance to create space for restorative materials, improve esthetics, and develop physiologic occlusion. It is usually advisable to assess esthetics, function, LFH, and response of the stomatognathic system to increased OVD by means of removable or fixed provisional appliances before definitive treatment. The following case report presents the multitude of factors considered in planning amount of OVD increase keeping in view its impact on LFH and facial esthetics, during rehabilitation of a patient with severely attrided dentition.How to cite this articlePawar RS, Kulkarni RS, Pimpale SK. Clinical Considerations while increasing Occlusal Vertical Dimension. Int J Prosthodont Restor Dent 2017;7(3):103-107.

Hereditary gingival fibromatosis with extreme ridge thickness and insufficient interarch distance: A clinical report of surgical and prosthetic management

Hereditary gingival fibromatosis is a rare genetic disorder resulting in gingival overgrowth that can be found in both dental arches. As a result of the gingival overgrowth and associated dental displacement, affected patients occasionally present with increased occlusal vertical dimension and/or inadequate lip closure. Depending on the disorder’s severity, these patients can be challenging to treat. This clinical report describes a comprehensive surgical and prosthetic approach to the rehabilitation of a middle-aged patient with severe manifestations of hereditary gingival fibromatosis and severe generalized chronic periodontitis.