Implant-borne Restorations Research Articles

Effect of apical root resection, orthodontic extrusion, and surgical crown lengthening on load capability

ObjectivesThis study aims to investigate the load-to-fracture of procedures changing crown-to-root ratio (RCRR) aimed to restore severely damaged upper central incisors to avoid tooth extraction compared to implant placement. There is no evidence on load capability after apical root resection (AR), orthodontic extrusion (OE), and surgical crown lengthening (SCL) in respect to RCRR, respectively.Material and methodsHuman maxillary central incisors were endodontically treated, decoronated, and divided into 4 groups (n = 48). The following specimen preparation was performed: (I) adhesive core-and-post build-up (control), (II) as (I) and 2 mm apical root resection (AR), (III) before adhesive core-and-post build-up teeth were shortened 2 mm coronally (OE) (IV) as (I), but specimens were embedded 4 mm instead of 2 mm below the CEJ (SCL), group (V) implant-borne restoration with individual all-ceramic abutments (n = 12; ∅4.1/l = 12 mm) (IBR). All specimens received all-ceramic crowns, thermo-mechanical (TML), and subsequent linear loading (LL) until failure. RCRR were calculated and log-rank, Kruskal–Wallis, Mann–Whitney U, ANOVA, and chi-square tests applied (p = 0.05).ResultsFracture loads after subsequent LL differed significantly (p = 0.001) between groups, while implants showed the highest values. Fmax median (min/max) were as follows: (I) 252 (204/542), (II) 293 (243/443), (III) 253 (183/371), (IV) 195 (140/274), and (V) 446 (370/539). Pair-wise comparison showed significant differences (p = 0.001) between group I/IV and group V, I, and IV (p = 0.045), II and IV (p = 0.001), and III compared to IV (p = 0.033), respectively. RCRR below 1 significantly increased load capability compared to RCRR = 1.ConclusionsOE appears to preferably ensure biomechanical stability of teeth that are endodontically treated and receive core-and-post and crown placement compared to SCL. AR has no adverse biomechanical impact. RCRR < 1 is biomechanically beneficial.Clinical relevanceFor endodontically treated and restored teeth, orthodontic extrusion should be preferred compared to surgical crown lengthening prior single-crown restoration. As orthodontic extrusion, apical root resection has no adverse effect on load capability. Single-crown implant-borne restorations are most load capable.

Clinical Practice Guidelines for Recall and Maintenance of Patients with Tooth-Borne and Implant-Borne Dental Restorations.

To provide guidelines for patient recall regimen, professional maintenance regimen, and at-home maintenance regimen for patients with tooth-borne and implant-borne removable and fixed restorations. The American College of Prosthodontists (ACP) convened a scientific panel of experts appointed by the ACP, American Dental Association (ADA), Academy of General Dentistry (AGD), and American Dental Hygienists Association (ADHA) who critically evaluated and debated recently published findings from two systematic reviews on this topic. The major outcomes and consequences considered during formulation of the clinical practice guidelines (CPGs) were risk for failure of tooth- and implant-borne restorations. The panel conducted a round table discussion of the proposed guidelines, which were debated in detail. Feedback was used to supplement and refine the proposed guidelines, and consensus was attained. A set of CPGs was developed for tooth-borne restorations and implant-borne restorations. Each CPG comprised (1) patient recall, (2) professional maintenance, and (3) at-home maintenance. For tooth-borne restorations, the professional maintenance and at-home maintenance CPGs were subdivided for removable and fixed restorations. For implant-borne restorations, the professional maintenance CPGs were subdivided for removable and fixed restorations and further divided into biological maintenance and mechanical maintenance for each type of restoration. The at-home maintenance CPGs were subdivided for removable and fixed restorations. The clinical practice guidelines presented in this document were initially developed using the two systematic reviews. Additional guidelines were developed using expert opinion and consensus, which included discussion of the best clinical practices, clinical feasibility, and risk-benefit ratio to the patient. To the authors' knowledge, these are the first CPGs addressing patient recall regimen, professional maintenance regimen, and at-home maintenance regimen for patients with tooth-borne and implant-borne restorations. This document serves as a baseline with the expectation of future modifications when additional evidence becomes available.

Management of Right Lower Posterior Edentulous Area With Bicon Implant: A Case Report

Posterior edentulous area and implant supported restorations are two important aspects in dentistry. Posterior edentulous area can't be restored effectively with partial denture or conventional bridge work The replacement of missing teeth with implant borne restorations in such conditions is gaining increasing popularity day by day. This case report describes the successful management of a posterior edentulous area using Bicon implant. The result was good, which further validate the use of this technique for suitable patient management.&#x0D; JCMCTA 2015 ; 26 (1) : 63-65

Disparity in embrasure fill and papilla height between tooth‐ and implant‐borne fixed restorations in the anterior maxilla: a cross‐sectional study

The objective of the present study was to compare inter-proximal fill and papilla height between different embrasures. One hundred and fifty non-smoking consecutive patients (mean age 54, range 32-73; 63 males and 87 females) without periodontal disease were selected in a multidisciplinary practice during regular supportive care. All had been treated for multiple tooth loss in the anterior maxilla at least 1year earlier by means of a fixed restoration on teeth (n=50) or implants (n=100) using straightforward procedures (without hard and/or soft tissue augmentation). Embrasure fill was assessed by means of Jemt's papilla index and papilla height was registered following local anaesthesia by means of bone sounding by one clinician. Tooth-pontic and tooth-implant embrasures demonstrated comparable inter-proximal fill and papilla height (≥58% Jemt's score 3; mean papilla height ≥4.1mm). Between missing teeth, embrasure fill and papilla height were lower regardless of the embrasure type. The implant-implant and implant-pontic embrasure demonstrated comparable outcome (≤42% Jemt's score 3; mean papilla height≤3.3mm; p≥0.416), which was significantly poorer when compared to the pontic-pontic embrasure (82% Jemt's score 3; mean papilla height 3.7mm; p≤0.019). Overall, papilla index and papilla height demonstrated a weak correlation (Spearman's correlation coefficient: 0.198; p=0.002). The re-establishment of a papilla is difficult when there is no tooth involved. In that scenario a short papilla should be expected and implant-borne restorations demonstrate the poorest outcome. Moreover, an implant with a pontic may not perform better than adjacent implants.

Morphofunctional aspects of dental implants

Although oral implantology is among the most beneficial developments of modern dentistry, the widely spread opinion that the long-term outcome of implants is superior to that of natural teeth has been refuted. To evade uncritical extractions, the morphofunctional properties of natural teeth and implant-supported restorations are compared from a proprioceptive and occlusal trauma perspective. The periodontal ligament of natural teeth provides the central nerve system with feedback for sensory perception and motor control. Conversely, the lack of such proprioception causes lower tactile sensitivity and less coordinated masticatory muscle activity in implant-borne restorations and makes them more prone to occlusal overload and possible subsequent failure. Moreover, occlusal anomalies may be conducive to parafunctional activity, craniomandibular disorder, tinnitus, and headache. Oral implantology, therefore, has to take appropriate account of occlusal conditions and the biomechanical and neuromuscular aspects of masticatory function.

Zirconia in Fixed Implant Prosthodontics

CAD/CAM technology in combination with zirconia ceramic has increasingly gained popularity in implant dentistry. This narrative review presents the current knowledge on zirconia utilized as framework material for implant-borne restorations and implant abutments, laboratory tests and developments, clinical performance, and possible future trends for implant dentistry are addressed. A review of available literature from 1990 through 2010 was conducted with search terms zirconia,""implants,""abutment,""crown," and "fixed dental prosthesis" using electronic databases (PubMed) and manual searching. Latest applications of zirconia in implant dentistry include implant abutments, multiple unit and full-arch frameworks as well as custom-made bars to support fixed and removable prostheses. High biocompatibility, low bacterial surface adhesion as well as favorable chemical properties of zirconia ceramics are reported. Zirconia stabilized with yttrium oxide exhibits high flexural strength and fracture toughness due to a transformation toughening mechanism. Preliminary clinical data confirmed the high stability of zirconia for abutments and as a framework material for implant borne crowns and fixed dental prostheses. Zirconia abutment or framework damage has rarely been encountered. However, veneering porcelain fractures are the most common technical complication in implant-supported zirconia restorations. These porcelain veneer failures have led to concerns regarding differences in coefficient of thermal expansions between core and veneering porcelain and their respective processing techniques. As presently evidence of clinical long-term data is missing, caution with regard to especially extensive implant-borne zirconia frameworks is recommended.

Long‐term vertical changes of the anterior maxillary teeth adjacent to single implants in young and mature adults

To evaluate the effects of the tooth eruption process on the position of teeth adjacent to implant-borne restorations in adult patients compared to patients in their late adolescence. The sample included 28 patients divided into two groups. A "young adult" group consisting of 14 patients, aged from 15.5 to 21 years, and a "mature adult" group consisting of 14 patients, aged from 40 to 55 years. All patients presented missing anterior teeth, requiring insertion of 40 implant fixtures (16 central incisors, 12 lateral incisors, 12 canines). The implants were of the Straumann Dental Implant System, clinically and radiologically re-evaluated 1 year or more after the surgical procedure (mean interval=4.2 years). Assessment of the eruption of the adjacent teeth was performed using the implant as a stable point of reference: measurements of the different reference points were compared after implant placement and at follow-up examination. In the "young adult" group, all patients showed infra-occlusion of the implant-supported crowns: the vertical step measured on radiographs varied between 0.1 and 1.65 mm. In the "mature adult" group, all patients showed a vertical difference between the teeth adjacent to the implant-supported crown and the implant: the measured step ranged from 0.12 to 1.86 mm. No difference was found in the amount of vertical eruption between male and female patients, nor according to localization of the implant. Mature adults can exhibit major vertical steps after anterior restorations with osseointegrated fixtures to the same extent as adolescents or "young adult" individuals with residuous growth potential.

USING RESTORATIONS BORNE TOTALLY BY ANTERIOR IMPLANTS TO PRESERVE THE EDENTULOUS MANDIBLE

This study quantifies the changes in bone height of the posterior area of the edentulous mandible when the load of complete dentures is borne entirely by anteriorly placed osseointegrated implants. Thirty-three patients, of whom there were radiographs from the beginning of implant loading and from a follow-up visit at least three years later (a mean of 6.6 years later), were included in the study. Working with panoramic radiographs, the authors took height measurements in the premolar area (15 millimeters distal to the most distal implants). A valid correction factor was available because implants of known length were proximal to the area being evaluated. The authors calculated descriptive statistics using means, standard deviations, medians and proportions as appropriate. A P-value of less than .05 was considered significant. Of the 33 subjects, most showed increases in bone height--29 (87.9 percent) on the right side and 28 (84.9 percent) on the left side. The mean change in all subjects was +1.0 mm (range -0.8 to +3.3 mm). A comparison of mandibular height at implant placement vs. follow-up showed a statistically significant increase bilaterally (P < .001). This study demonstrates that dentures for edentulous mandibles that are borne totally by implants in the anterior area conserve or enhance the bone of the posterior portion of the mandible. An important future study should test the effect of implant-assisted restorations for the edentulous mandible that load the posterior ridge (a bar clasp, for example). One of the considerations in planning treatment for the edentulous mandible should be the preserving effect of totally implant-borne restorations vs. the continued resorption of the body of the mandible with conventional dentures.

The periodontist and the edentulous area – localised ridge augmentation

The replacement of missing dentition by implant-borne dental restoration has been shown to be a highly predictable treatment method with good long-term prognosis. Subsequently, the use of implant-borne restorations has gradually increased over the use of conventional partial dentures and fixed restorations in recent years. Sufficient bone volume is the most important factor for successful implant-borne restoration, but often an insufficient amount of bone is found at implant sites. A new surgical approach to enlarge the width of alveolar crest was introduced by Buser et al. in 1996. This new approach is based on the principle of guided bone regeneration technique using a barrier membrane with autogenous bone grafts in the form of bone blocks, chips and particles. This promising new surgical technique allows placement of dental implants for implant-borne restorations in partially edentulous patients who were previously not considered to be implant candidates because of insufficient bone at the implant sites.

A modified impression technique for implant-supported restoration

An impression technique is proposed for construction of implant-borne restorations that uses a modified autopolymerizing resin custom tray to allow splinting of the impression copings directly to the tray. This method eliminates the use of the dental floss-autopolymerzing resin complex, thus decreasing resin distortion and simplifying the clinical procedures.