Interproximal Contact Research Articles

Prevalence of OXIS Contacts between the Primary Molars in 3 to 9 Years Old Children: A Cross-sectional Study

Introduction: Interproximal contacts between primary teeth have traditionally been reported as broad and flat. A new system of classification for contacts called OXIS- O (open contact), X (point contact), I (straight contact), and S (curved contact) was introduced in 2018, based on the shapes observed occlusally. Understanding interproximal contacts in primary teeth is essential to comprehend the caries risk of the individual. Aim: To assess the prevalence of OXIS contact areas between non carious primary molars in 3 to 9 years old children and to determine the most common type of contact before and after the eruption of the first permanent molar. Materials and Methods: A cross-sectional study was conducted to determine the prevalence of the types of contacts between primary teeth through direct observation in a sample size of 260 contact areas. The study was carried out in the Department of Paediatric and Preventive Dentistry, Navi Mumbai, India, between August 2022 to February 2023. Ethical clearance from the university was obtained. A single calibrated examiner examined photographs of the interproximal contacts between primary molars. The contacts were assessed as O (open contact), X (point contact), I (straight contact), and S (curved contact) using the OXIS classification system. The prevalence of each contact type was recorded. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) 18.0 software. The prevalence of contact types was recorded in numbers and percentages. A comparison of contact types before and after the eruption of the first permanent molar was conducted using the Chi-square test. Result: The most common contact type was I (65.00%) both before and after the eruption of the first permanent molar. This was followed by S (19.62%), X (11.15%), and O (4.23%) in the primary dentition. After the eruption of the first permanent molars, I contact was the highest at 66.41%, followed by S (20.90%), X (12.68%), and O (0%). Conclusion: This study confirms the presence of O, X, I, and S types of interproximal contact areas in caries-free primary molars in 3 to 9 years old children.

Interproximal contact loss between implant-supported prostheses: a clinical report

Interproximal contact loss between implant-supported prostheses: a clinical report

Optical impressions assessment for overlay restorations with rubber dam: A clinical trial

ObjectiveThe possibility of making impressions of teeth prepared with a rubber dam in place has been proposed; however, this requires trimming and rescanning the mesh, which has been described as a cause of accuracy loss. This study aims to clinically determine whether overlay restorations obtained from a scan with a rubber dam in place have equivalent marginal fit, contact points, and occlusal fit to the same type of restorations obtained from a scan without a rubber dam. Material and methodsThirty patients who underwent overlay restoration of a molar with at least one neighbouring tooth were selected. After tooth preparation, two scans were performed: one without a rubber dam and the other with a rubber dam. Restorations were randomly created from one scan or another. The marginal fit, interproximal contact points, and occlusal fit were evaluated clinically. Two meshes, with and without rubber dams, were also compared. ResultsNo significant differences were observed in the clinical evaluation of the overlays made of the two meshes. The trueness of the mesh from the impression made with a rubber dam with respect to the mesh without a rubber dam was about 40 µm in the critical areas of the preparation (margins, intaglio, and interproximal contact points). ConclusionsThe results of this study show that under the conditions performed and with the equipment used, there are no significant clinical differences between overlay restorations made from a scan with a rubber dam and those made from a scan without a rubber dam. Clinical significanceScanning with a rubber dam in place may be a valid option for certain types of restorations under certain clinical conditions.

Trueness, precision, time-efficiency and cost analysis of chairside additive and subtractive versus lab-based workflows for manufacturing single crowns: An in vitro study

PurposeTo evaluate the trueness, precision, time efficiency, and cost of three different workflows for manufacturing single crowns (SCs). MethodsA plaster model with a prepared tooth (#15) was scanned with an industrial scanner, and an SC was designed in computer-assisted-design (CAD) software. Ten SCs were printed with a hybrid composite (additive chairside) and a stereolithographic (SLA) printer (Dfab®), 10 SCs were milled in lithium disilicate (subtractive chairside) using a chairside milling unit (inLab MC XL®), and 10 SCs were milled in zirconia (lab-based) using a five-axis laboratory machine (DWX-52D®). All SCs were scanned with the same scanner after polymerization/sinterization. Each scan was superimposed to the marginal area of the original CAD file to evaluate trueness: absolute average (ABS AVG), root mean square (RMS), and (90˚–10˚)/2 percentile were calculated for each group. Marginal adaptation and quality of the occlusal and interproximal contact points were also investigated by two prosthodontists on 3D printed and plaster models. Finally, the three workflows’ time efficiency and costs were evaluated. ResultsAdditive chairside and subtractive lab-based SCs had significantly better marginal trueness than subtractive chairside SCs in all three parameters (ABS AVG, p < 0.01; RMS, p < 0.01; [90˚–10˚]/2, p < 0.01). However, the two prosthodontists found no significant differences between the three manufacturing procedures in the quality of the marginal closure (p = 0.186), interproximal (p = 0.319), and occlusal contacts (p = 0.218). Both time efficiency and cost show a trend favoring the chairside additive workflow. ConclusionsChairside additive technology seems to represent a valid alternative for manufacturing definitive SCs, given the high marginal trueness, precision, workflow efficiency and low costs. Statement of clinical relevanceAdditive chairside manufacturing of definitive hybrid composite SCs is now possible and shows high accuracy, time efficiency, and competitive cost.

Modified interproximal tunneling technique with customized sub-epithelial connective tissue graft for gingival papilla reconstruction: report of three cases with a cutback incision on the palatal side

BackgroundGingival papilla defects, which cause an unpleasant appearance and involve the upper anterior teeth, may be triggered by several factors. Several noninvasive and invasive techniques have been proposed for gingival papilla reconstruction. The combination of interproximal tunneling and customized connective tissue grafts (CTGs) has shown promise in papilla augmentation. However, due to the narrowness and limited blood supply of the gingival papilla, the long-term outcomes of these techniques remain unpredictable. Therefore, achieving tension-free coronal advancement of the interdental papilla and proper placement of the CTG is crucial for successful long-term outcomes and could provide widely applicable methods for papilla augmentation.Case reportIn this study, we enrolled three patients with gingival papilla defects in the maxillary anterior teeth. For reconstruction, we proposed a modified interproximal tunneling (MIPT) technique combined with a CTG. A crucial modification based on previous studies involved adding a cutback incision to the base of the palatal vertical incision, resulting in tension-free healing. Additionally, the CTG was sutured upright to further enhance the height of the gingiva papilla. To evaluate the efficacy of the MIPT technique, the clinical parameters—including the Jemt papilla index and the distance from the tip of the papilla to the interproximal contact point—were examined using a periodontal probe (UNC15, Hu-friedy) at baseline and 12 months after surgery. All three patients achieved satisfactory papilla reconstruction 12 months after the surgery. These three cases were used to evaluate the efficacy of the MIPT technique combined with the customized CTG. An average increase in the Jemt papilla score from 1.6 to 2.8 and a reduction in the distance from the papilla tip to the contact point of adjacent teeth from 2 mm to 0.08 mm were observed 12 months after surgery.ConclusionThe preliminary results confirmed that this technique holds promise for gingival papilla augmentation between tooth/tooth or tooth/implant.

Prevalence of different types of interproximal contacts in the permanent dentition - a study cast evaluation.

A new classification called OXIS was proposed for categorizing the interproximal contacts of primary molars, modified for the primary canines and its prevalence was established. No such information is available for the permanent dentition. Hence, the aim was to establish the variations in interproximal contacts of the permanent dentition and thereby modify the OXIS classification of primary molars and primary canines to the permanent dentition. We propose a study-cast-based classification of interproximal contacts of the permanent dentition. Three hundred and forty-three pretreatment casts of patients based on an inclusion and exclusion criteria were selected. Contacts of posterior teeth were classified based on OXIS classification of interproximal contacts, and its modification was used for anterior teeth. Among the posterior contacts, the 'O' type of contact was least prevalent, while most prevalent was the 'S' type for second molar-first molar contact, 'I' type for the first molar-second premolar contact, and 'X' type for the second premolar-first premolar contact. Among the anterior contacts, least prevalent was 'S1' type for the first premolar-canine contact, and I type for the canine-lateral incisor and the lateral incisor-central incisor contacts. There was no statistical significance between right- and left-side contacts ( P > 0.05) while significance was seen between maxillary and mandibular contacts ( P < 0.05). Similarity of contacts ranged from 5.17% to 10.05%. The OXIS classification is applicable to posterior permanent teeth, and its modification is representative of anterior permanent teeth.

Interproximal contact loss between implant restorations and adjacent natural teeth: A systematic review and meta-analysis.

This systematic review was conducted to evaluate the prevalence of interproximal contact loss (ICL) between implant restorations and adjacent teeth in relation to age, gender, follow-up time, and arch location. This study followed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and was registered in the Open Science Framework (OSF). The formulated population, intervention, comparison, outcome (PICO) question was "What is the prevalence of the ICL between implant restoration and adjacent teeth?" The search strategy used four main electronic databases and an additional manual search was performed until February 2023. Clinical studies that evaluated the prevalence of interproximal open contact between implant restorations and adjacent teeth were included. A qualitative analysis for clinical studies was used to assess the risk of bias. In addition, a single-arm meta-analysis of proportion was performed to evaluate the percentage of mesial versus distal open contact and total ICL between implant restoration and adjacent teeth. Fifteen studies published between 2014 and 2023 met the eligibility criteria. Seven studies presented ICL rates higher than 20%. All studies evaluated ICL in posterior regions (molar, premolar area). Five studies had an ICL rate lower than 50% and three studies had an ICL rate higher than 50%. One study assessed the interproximal contact at three months post-restoration insertion, four studies assessed the interproximal contact at 1-year follow-up and nine studies evaluated the interproximal contact over 2 years of follow-up. Mesial and distal ICL rates were 44.2% (95% CI: 30.6% to 58.6%) and 27.5% (95% CI: 10.5% to 55.0%), respectively. The heterogeneity between studies was high (I2 (95% CI) = 87.8% (75.9% to 93.8%). Based on the results of the included studies, the prevalence of ICL was high, occurring more frequently at the mesial contact. There were no significant differences in relation to age, gender, and arch location.

Comparison of Prevalence of Oxis Contact in Primary Maxillary and Mandibular Teeth: A Retrospective Cohort Study

Aim: The purpose of the present study was to evaluate four different types of OXIS contact areas (open [O], point [X], straight [I], and curved [S]) in primary teeth using cone beam computed tomography (CBCT) among 3- to 9-year-old children.&#x0D; Methods: A retrospective cohort study was performed using cone-beam computed tomography images of children, available from January 1, 2022, to July 31, 2023 in Mathura district showing the presence of caries-free contact area between primary right maxillary and mandibular 1st and 2nd molar. In this study, 65 selected contacts using OXIS criteria from the occluso-cervical and axial view at coronal level using CBCT.&#x0D; Result: Based on the shapes observed, the results showed four distinct types of contact regions between the primary molars, namely, O type, X type, I type, and S type; hence, the suggested categorization is known as OXIS. I type was the most prevalent pattern in the maxilla (47.06%), while O type was the most prevalent pattern in the mandible (50%).&#x0D; Conclusion: There are four types of intact interproximal contact areas between primary molars, which can be evaluated in three dimensions. These types are O, X, I and S. In maxilla, pattern was&#x0D; I &gt; O &gt; X &gt; S whereas in mandible pattern was O &gt; X &gt; I = S.

Surface characteristics and wettability of novel gingival col designed 3-D printed dental sectional matrices.

The physical properties and wettability of 3-D printed Polyethylene terephthalate - glycol (PET-G) and Poly(lactic) acid (PLA) dental sectional matrices were investigated. Experimental matrices was designed in a rectangular shape one-side depression corresponds to gingival col and without sharp edges and printed on FDM machine Ender Pro 3 (Creality®, Shenzhen, China). The physical textures, thicknesses, water contact angles were compared to conventional stainless steel (SS) matrix. PETG and PLA sample matrices were clinically single-side smooth compared to SS matrix. PETG specimens had uniformly 0.055 mm whereas PLAs were non-uniformly ∼0.065-0.075 mm in thickness. The mean ± standard deviation (SS) of contact angle for SS was 78.29 ± 0.18, for PETG was 72.09 ± 0.94, for PLA was 73.03 ± 1.17. PETG and PLA dental matrices might have desirable properties: being hydrophobic, non-charged, easy to manufacture and mimicking the gingival col depression in the dental interproximal contact area.

The incidence and severity of open gingival embrasures in adults treated with clear aligners and fixed appliances: a retrospective cohort study

BackgroundTo evaluate the incidence and severity of open gingival embrasures (OGEs) in adult patients treated with clear aligners and fixed appliances.MethodsTwo hundred non-extraction adult subjects with less than 5 mm of crowding (mean age, 24.6 ± 3.8 years) were enrolled in this retrospective study. The subjects were divided into the clear aligner (n = 100) and fixed appliance group (n = 100). The intraoral photographs were utilized to determine the incidence of OGEs in the upper arch between maxillary central incisors, as well as the lower arch between mandibular central incisors. Crown overlap, crown shape, posttreatment root angulation, the distance from the interproximal contact point (ICP) to the alveolar bone crest (ABC) after treatment and interproximal enamel reduction (IPR) were determined in the two groups.ResultsThe incidence of OGEs between maxillary and mandibular central incisors after orthodontic treatment was 35.0% and 38.0% in the clear aligner group, respectively, significantly higher than that (18.0% and 24.0%) in the fixed appliance group (P < 0.05). The average area of an OGE after clear aligner treatment was larger both in the maxilla (0.16 ± 0.12mm2) and mandible (0.21 ± 0.24mm2) compared with that (0.05 ± 0.03mm2 and 0.05 ± 0.06mm2) after fixed appliance treatment (P < 0.05). No difference was found regarding pretreatment crown overlap, crown shape, treatment duration, posttreatment root angulation, amount and distribution of IPR and the distance from ICP to ABC.ConclusionsThe incidence and severity of OGEs were higher in adults treated with clear aligners. Clinicians should be aware of the risk of OGEs during treatment with clear aligners.

Isolated periodontal pockets: a clinical review

An isolated periodontal pocket is a perplexing clinical entity that usually poses a diagnostic challenge to the oral health professional. Although periodontal pockets are easy to detect, they can be easily missed during a routine clinical examination. The broad range of aetiological factors that can result in an isolated periodontal pocket makes identifying the cause difficult. The aetiology can be as simple as an overhanging restoration or food impaction due to open interproximal contacts, to more complex and uncommonly occurring presentations, such a palato-radicular groove or cemental tears. Although previous classifications proposed by the American Academy of Periodontology and European Federation of Periodontology have discussed this topic under different headings, an explicit classification on isolated periodontal pockets based on aetiology is currently missing. Isolated periodontal pockets are easily undiagnosed, with associated cases presenting with substantial destruction necessitating complex multidisciplinary treatment. This article highlights the various causes of an isolated periodontal pocket, and provides a systematic and easy clinical aetiology-based classification. The proposed classification categorizes isolated periodontal pockets into those occurring due to: (1) developmental anomalies of the teeth; (2) iatrogenic causes; and (3) pathological conditions. Further studies are essential to validate this classification. CPD/Clinical Relevance: Early detection of easily missed isolated periodontal pockets is of clinical value during initial screening to avoid delayed diagnosis and treatment.

A systematic review of dental instruments used for interproximal contact point restoration in posterior teeth

Relevance. Anatomical and functional restoration of an interproximal contact point is an important step in the comprehensive treatment and prevention of periodontal disease. A lot of tools are applicable for interproximal contact point restoration. Since the first application of the first composite material in dentistry, over one hundred instruments have been proposed, with different characteristics and positive and negative features. The variety available on the market may lead to a mistake in the instrument choice, which decreases the dentist's work quality. Purpose. To systematically review the clinical experience in dental instruments used for posterior tooth interproximal contact point restoration.Materials and methods. The review analyzed Russian and international studies on the dental instruments used for posterior tooth interproximal contact point restoration that met the specified criteria. The primary search was performed in the databases Google Scholar, ScienceDirect, PubMed, ResearchGate, and eLIBRARY.RU, using the keywords: контактный пункт, инструмент, матрица, клин, interproximal contact, matrix, wedge, dental instrument in the Russian and English languages.Results. We selected 24 original primary prospective studies on instruments for an interproximal contact point restoration certified in Russia. All instruments were divided into two groups: matrix systems (Palodent V3, HAWE SuperMat, TOR VM) and additional instruments (Contact-Pro-2, OptraContact).Conclusion. The experience of the instruments’ clinical application and the history of their creation have demonstrated a shift towards the anatomically-guided reconstruction of lost tissue. Thus, developing a tool for the anatomical and functional restoration of an interproximal contact point is a challenge for modern dentistry.

Factors influencing the successful eruption of the maxillary third molar after extraction of the maxillary second molar

This study evaluated the occlusal status of the maxillary third molars that erupted spontaneously after extraction of the maxillary second molars and investigated the factors that influenced the occlusal status of the maxillary third molars. We assessed 136 maxillary third molars in 87 patients. Alignment, marginal ridge discrepancy, occlusal contact, interproximal contact, and buccal overjet were used to score the occlusal status. Occlusal status was classified as good (G group), acceptable (A group), and poor (P group) for the maxillary third molar at its full eruption (T1). The Nolla's stage, long axis angle, the vertical and horizontal position of the maxillary third molar, and the maxillary tuberosity space were assessed at the time of maxillary second molar extraction (T0) and T1 to identify factors influencing the eruption of the maxillary third molar. G, A, and P groups comprised 47.8%, 17.6,% and 34.6% of the sample, respectively. Age was the lowest in the G group at both T0 and T1. The maxillary tuberosity space at T1 and the amount of the change of maxillary tuberosity space were the largest in the G group. There was a significant difference in the distribution of the Nolla's stage at T0. The proportions of the G group were 60.0% in stage 4, 46.8% in stages 5 and 6, 70.4% in stage 7, and 15.0% in stages 8-10. According to multiple logistic regression analysis, stages 8-10 for the maxillary third molar at T0 and the amount of the change of maxillary tuberosity were negatively associated with the G group. Good-to-acceptable occlusion was seen in 65.4% of the maxillary third molars after maxillary second molar extraction. Insufficient increase in the maxillary tuberosity space and Nolla stage 8 or higher at T0 negatively influenced the maxillary third molar eruption.

Correlation between the Inner Canthal Distance and the Upper Central Incisor Mesiodistal Width Using the Decreasing Function of the Golden Ratio

Background: Optimal aesthetics without sacrificing function is one of the main goals of prosthodontists. The face is the most noticeable aspect of the body, and a grin significantly increases one's sense of self-worth. Since aesthetics and subsequently self-esteem are both impacted by the loss of anterior teeth, this frequently causes psychological anguish for the patient. The quality of life and self-esteem of patients are improved by the proper tooth location and choice employing the art of dentogenics to simulate real teeth. Aim: To determine whether there is a relationship between the average mesiodistal width of the upper central incisor and the inner canthal distance when the ICD is multiplied by the decreasing golden ratio, as well as to evaluate the significance of this relationship in predicting mesiodistal width of the upper central incisor in subjects with edentate disease. Methodology: This cross-sectional study was carried out at Department of Prosthodontics, Bacha Khan College of Dentistry Mardan from October 2022 to March 2023. Four hundred and fifty dentate Pakistani subjects without dental or facial abnormalities, aged 18 to 40, were examined. With the use of veriner callipers, the central upper incisors were noted mesiodistally amongst the interproximal contact sites and inner canthal space. The inner canthal space was multiplied by 0.618, and the width of the central incisor was calculated by dividing the result by 2. Results: Statistically significant finding demonstrated with inner canthal distance was exposed to the golden ratio. There was only a modest link among the practical mesiodistal width of the central upper incisors and the estimated central upper incisor width. Conclusion: For edentulous patients, choosing the width of the upper central incisors using the decreasing value of the inner canthal distance's golden ratio was not a valid predictor. Keywords: Edentulous, Golden ratio, Inner canthal distance (ICD)

“Comparing the effectiveness, acceptability and oral hygiene status between vacuum formed retainer and Begg’s retainer”: a pilot study

BackgroundRecently, Vacuum formed retainers (VFRs) are preferred as an Orthodontic retention appliance over conventional Begg’s retainers. Very few studies have been conducted between VFRs and Begg’s retainers. Hence, this study aims at assessing the effectiveness, oral hygiene and acceptability between VFRs and Begg’s retainers with a follow up period of 1 year.MethodsEighty patients who completed fixed Orthodontic treatment were included. Retainers were delivered on the same day of debonding. Retainer 1/ R1 stands for VFRs and Retainer 2/ R2 stands for Begg’s retainers. The retainers were randomly allocated to both the arches. 40 VFRs and Begg’s retainers in maxillary and mandibular arch were given respectively.Effectiveness, oral hygiene condition were performed at T0 (After debonding), T1 (3 months after using retainers), T2 (6 months after using retainers), T3 (9 months after using retainers), T4 (12 months after using retainers) follow up stages, except the feedback form and the breakage of retainers that were filled at T4 stage.ResultsBoth R1 and R2 retainers showed improvement in teeth alignment in both the arches at follow up stages. Interproximal contacts in maxillary and mandibular arch with VFRs and Begg’s retainers improved to 77.5% and 82.5% respectively. Considering the marginal ridge, Begg’s retainers and VFRs showed 95%, 55% increased proportion at T4 respectively (p < 0.05). Patients wearing Beggs’s retainers had significantly better (p < 0.05) oral hygiene status.Significant differences were observed with Begg’s retainers in teeth biting, whereas no significant difference was found with fitting of appliance (p = 0.180) and gingival irritation (p = 1.000). VFRs were well accepted aesthetically that was significant. Retainers were prone to breakage but was not significant (p = 0.162).ConclusionBegg’s wrap around retainers maintain good oral hygiene, improve the teeth alignment, interproximal contact and marginal ridges post Orthodontic treatment with better fitting of the appliance. VFRs are also preferred as they are good in maintaining proper teeth alignment with progressive improvement in the interproximal contacts and are aesthetically pleasing.

An evaluation of the interproximal contacts of the permanent dentition - A study cast based classification

Background: A new classification called OXIS was proposed for categorizing the interproximal contacts of primary molars, modified for the primary canines and its prevalence was established. No such information is available for the permanent dentition. Hence, the aim was to establish the variations in interproximal contacts of the permanent dentition and thereby modify the OXIS classification of primary molars and primary canines to the permanent dentition. Methods: We propose a study-cast-based classification of interproximal contacts of the permanent dentition. Three hundred and forty-three pretreatment casts of patients based on an inclusion and exclusion criteria were selected. Contacts of posterior teeth were classified based on OXIS classification of interproximal contacts, and its modification was used for anterior teeth. Results: Among the posterior contacts, the ‘O’ type of contact was least prevalent, while most prevalent was the ‘S’ type for second molar-first molar contact, ‘I’ type for the first molar-second premolar contact, and ‘X’ type for the second premolar-first premolar contact. Among the anterior contacts, least prevalent was ‘S1’ type for the first premolar-canine contact, and I type for the canine-lateral incisor and the lateral incisor-central incisor contacts. There was no statistical significance between right- and left-side contacts (P &gt; 0.05) while significance was seen between maxillary and mandibular contacts (P &lt; 0.05). Similarity of contacts ranged from 5.17% to 10.05%. Conclusion: The OXIS classification is applicable to posterior permanent teeth, and its modification is representative of anterior permanent teeth.

Anterior Matrix Systems for Composite Restorations: A Review.

In the field of restorative dentistry, composite resins have emerged as the most utilized materials. They revolutionized the cosmetic approach to anterior tooth treatment since their introduction to dental practice. In cases where one or more of the tooth's walls are absent, matrices are employed to assist in the creation of the proper anatomic contour and proximal contacts without the occurrence of gingival overhangs. Matrices come in a variety of designs suitable for various therapeutic conditions. Depending on the level of tooth destruction, they might range from a simple metal or plastic strip to a circumferential ring of metal surrounding the entire crown. Although the handling characteristics of modern composites have significantly improved, dentists still encounter challenges with the development of good interproximal contact and proper anatomical contour. The utilization of an anterior matrix system can be paramount in achieving these objectives.

Clinical Technique to Calculate Pressures in Interproximal Dental Points

The adjustment of the interproximal contact points (N) is important to avoid caries, periodontal problems, and halitosis. When this pressure is evaluated, a correct restoration can be made with composite or prosthesis in those points. A metal strip (6 mm wide and 0.03 mm thick) is placed interproximal between adjacent teeth and attached to a dynamometer through a Tofflemire matrix holder. The formula to use is N = Fd / 2μ. The dynamic force of friction (Fd) is given by the dynamometer when the strip begins to move between the teeth. A coefficient of friction (μ) for wet enamel-steel metal of 0.176, previously calculated, is used. In this way, to measure adjustments of interproximal points we use the formula N = Fd / 0.352. Electronic experimental instruments are much more complicated to use than the instrument described here. The materials used are for daily use in any dental clinic and it is easy to use. The coefficient of friction depends on the humidity of the surface, but here the natural saliva of the patient is used as a lubricant. This simple technique allows the measurement of the fits of interproximal contact points so that dental restorations can be improved at those points.

How does arch form and interproximal contact size affect the 3D displacements and rotations of teeth: a finite element analysis.

The objective of this study was to determine how arch form and interproximal contact size displace mandibular teeth subjected to an anterior component of force (ACF). Nine finite element models (FEM) of the mandibular arch were developed using Ansys® v. 16.0 software. They were designed to evaluate the effects of three arch forms (triangular, oval, and square) and three contact sizes (point-to-point, 1 mm diameter, and 2 mm diameter). All nine models were subjected to an ACF of 53.8 N (5486 gm). Three-dimensional tooth rotations and displacements of the mandibular teeth were evaluated, from the right first molar to the left first molar. Arch form had a greater effect on tooth movements than contact size. Triangular arches and point-to-point contacts produced the greatest displacements and rotations of teeth. Oval arches with 2 mm wide interproximal contact points showed the greatest stability. The right first premolar showed the greatest displacements in all of the models. Arch form and contact size affect interproximal tooth stability. Teeth are least stable in narrow arches with point-to-point interproximal contacts, and most stable in wider arches with larger contacts.

Restoring the functionality of implant-supported prostheses with a reloading technique: A clinical report

The prevalence of infraocclusion and/or loss of interproximal contact areas with implant-supported restorations is high, and replacement of these prostheses has been advocated for the treatment of mild or moderate infraocclusion; however, replacement is complicated if the manufacturer of the implant is unknown. A technique is presented for correcting the infraocclusion of posterior prostheses that are directly connected to the implant. Advantages include possibly preventing marginal bone loss secondary to the removal and reconnection of the prosthetic attachments and reducing the number of appointments.