Flemming Isidor

Timing of implant placement relative to tooth extraction

In recent years, immediate or early implant placement after tooth extraction has becoming more common. The present review focuses on the clinical outcome of immediate or early implant placement. Only limited knowledge exists about most of the factors with particular significance for this treatment mode. Randomized controlled clinical studies comparing the various treatment protocols are scarce. With the background in the existing literature some conclusions can be drawn with caution. Survival rates for implants placed immediately, early, delayed, or late seem to be similar in the short perspective and amounts to approximately 95%. Successful immediate implant placement may be possible in all regions of the jaws, although replacement of molars is more challenging. Chronic infection is not an absolute contraindication for immediate implant placement. It is controversial whether immediate placement of implants may preserve the alveolar bone. Small gaps between implant surface and socket wall have a potential for spontaneous healing. No consensus exists on the need for bone augmentation in these situations. With the limited information available it may be stated that a good prognosis can be obtained following immediate/early functional or non-functional loading of immediately placed implants. However, higher risk of failures seems to exist compared with a delayed, conventional approach. It is advocated that this treatment modality should be restricted to skilled well-trained teams. Data on the aesthetic outcomes following immediate/early implant placement are inconclusive, but this treatment can offer high patient satisfaction with the aesthetic and functional outcomes.

A clinical evaluation of porcelain inlays

Sparse data are available concerning the survival rate of porcelain inlays or onlays to inform the dentist and address the expectations of patients. A total of 25 posterior porcelain inlays were inserted by two dentists at a private Danish clinic; the time elapsed since cementation was 20 to 57 months (average 40.4 months). Tooth preparations for MOD porcelain inlays were completed for 13 premolars and 12 molars but most did not include cuspal coverage. All inlays were constructed at the same commercial dental laboratory and according to the manufacturers recommendations; they were etched and treated with silane before they were cemented. The cementation included etching of cavosurface enamel and treatment of the dentin with a dentinal bonding system. A thin layer of composite resin luting agent was applied to the tooth preparation before the porcelain inlays were cemented. The first 10 porcelain inlays were cemented with a light-curing composite resin cement and the remaining 11 with a dual-curing composite resin cement. Twelve of the 25 porcelain inlays failed and were replaced during the observation period. Ten failures were due to a fracture of the inlay, one was caused by secondary caries, and the final failure was attributed to a marginal gap between the inlay and proximal tooth surface. Porcelain inlays cemented with light-curing composite resin exhibited more failures (p = 0.05) than those cemented with dual-curing composite resin. In addition, more failures (p = 0.07) were recorded among inlays inserted in molars than among those in premolars.

Risk factors for tooth loss in an adult population: a radiographic study

AIM The aim of the present study was to estimate the incidence and identify risk factors for tooth loss during a 5-year period in a randomly selected Danish population. MATERIAL AND METHODS In 1997 and 2003, 473 randomly selected adults received a full-mouth radiographic examination. The total number of teeth was 12,444. For each tooth, the following information was recorded from the radiographs: marginal bone level, filling, crown, root canal post, root filling, apicectomy, periapical status and caries lesion. Unconditional and conditional logistic regression analyses were used to identify risk factors for tooth loss. RESULTS During the study period, 107 teeth in 60 individuals were lost. On the individual level, reduced marginal bone level and apical periodontitis (AP) were highly associated with tooth loss. On the tooth level, a reduced marginal bone level, AP and apicectomy were strongly associated with tooth loss. Canines were not lost often, whereas tooth loss was more frequently observed in molars and premolars than in incisors. CONCLUSIONS A reduced marginal bone level and AP were associated with tooth loss over time. Furthermore, there was a higher risk of tooth loss in the posterior regions than in the anterior region.

Detection of vertical root fractures by cone-beam computerized tomography in endodontically treated teeth with fiber-resin and titanium posts: an in vitro study.

OBJECTIVE The aim of this study was to assess the performance of 2 cone-beam computerized tomography (CBCT) systems for detecting vertical fractures in root-filled teeth with fiber-resin or titanium posts. STUDY DESIGN CBCT images acquired with the use of Scanora 3D and i-CAT of roots with fiber-resin (n = 30) or titanium (n = 29) posts, before and after the induction of fractures, were assessed by 6 radiologists using Ondemand 3D software. Interobserver agreement was analyzed using kappa statistics. Sensitivity, specificity, accuracy, and positive and negative predictive values were compared with analysis of variance/Student-Newman-Keuls test. RESULTS Interobserver agreement for fiber-resin posts ranged from 0.5 to 0.7 (Scanora 3D) and 0.35-0.76 (i-CAT). For titanium posts, ranged from 0.42 to 0.80 (Scanora 3D) and 0.31-0.73 (i-CAT). Higher sensitivity (0.85; P < .05) and negative predictive values (0.88; P < .001) were observed for i-CAT in roots with fiber-resin posts than with other combinations. CONCLUSIONS The diagnostic performance for detecting vertical fractures was higher for roots with fiber-resin than with titanium posts.

Cantilevered fixed partial dentures in a geriatric population: Preliminary report

This study has shown that treatment with distally extending cantilever fixed partial dentures is a favorable alternative to treatment with removable partial dentures in elderly patients with reduced dentition. In patients with anterior teeth and one or two premolar teeth remaining in the mandible, sufficient occlusal stabilization for a maxillary complete denture was provided by a two- or three-unit cantilever fixed partial denture. A pronounced improvement in chewing function and stability of the maxillary denture was expressed, even by patients who were previously well adapted to wearing removable partial dentures.

Resin-bonded prostheses for posterior teeth

This study evaluated fixed partial dentures bonded with resin to dentin on posterior teeth with minimal tooth preparation. The patients included were missing at least one premolar or first molar. The abutment teeth next to the modification spaces were moderately restored with MOD or class II restorations on most of the teeth. A total of 20 patients with 23 fixed partial dentures were included in the study. After removal of existing restorations, the abutment teeth were prepared to eliminate undercuts on the perimeter of the preparations. Undercut areas within the preparation were not filled but were blocked out later in the laboratory. The fixed partial dentures employed inlays as retainers for a metal ceramic pontic. The metal framework was cast in a high noble gold alloy. The areas of the retainers to be bonded were treated with the Kulzer Silicoater method. Immediately before cementation, enamel was etched and exposed dentin was treated with Gluma. Kerrs resin bonded bridge cement was used for cementation. Patients were recalled after periods of 1 week, 1 month, 6 months, 1 year, 2 years, and 4 years for evaluation. None of the restorations lost retention and no major adverse effects were observed in the 4-year follow-up period.

Papilla dimension and soft tissue level after early vs. delayed placement of single‐tooth implants: 10‐year results from a randomized controlled clinical trial

AIM To present the10-year esthetic outcome data for single-tooth implants placed early or delayed after tooth extraction. MATERIAL AND METHODS Forty-four patients randomly allocated to two equal size groups were treated with a single-tooth implant approximately 10 days (Ea; N = 22), or 3 months (De; N = 22) after tooth extraction. Healing abutments were mounted after 3 months of submerged healing, and metal-ceramic crowns cemented after one additional month. Presence of buccal bone defects was registered at the second-stage surgery. Patients attended control visits 1 week and 1-1.5 years after mounting of the crown and 5 and 10 years after implant placement. Marginal bone level at the implant and the adjacent teeth as well as the distance between the implant and the teeth were measured in standardized periapical radiographs. The papilla dimension and clinical crown height (CCH) were assessed on clinical photographs by an experienced prosthodontist. RESULTS Two Ea and one De implants failed to osseointegrate. Twenty-eight patients (13 Ea and 15 De) who attended all four control visits were included in the data analysis. Complete papilla fill interproximally was achieved in one-third of the cases and an appropriate clinical crown height in <60% after 10 years. Although not statistically significant, early-placed implants tended to be superior to delayed-placed implants regarding soft tissue appearance just after crown delivery and after 10 years. An improvement in papilla dimensions was seen during the follow-up period for both groups while the CCH was unchanged. The implant region (anterior vs. posterior) did not significantly influence the papilla or CCH scores while younger patients (<50 years of age) received significantly better papilla scores than older patients (≥ 50 years). An apically located bone level at the tooth neighboring the implant influenced negatively the papilla dimension. In contrast, the presence of a bone defect buccally to the implant at second-stage surgery did not have a negative impact on the CCH 10 years after implant placement. CONCLUSION Early placement of single-tooth implants after tooth extraction performed equally to delayed placement in regard to the esthetic outcome of the soft tissues after 10 years in function.

Optimization of jaw muscle activity and fine motor control during repeated biting tasks

OBJECTIVE To investigate if repeated holding and splitting of food morsel change the variability of force and jaw muscle activity in participants with natural dentition. METHODS Twenty healthy volunteers (mean age=26.2±3.9 years) participated in a single session divided into six series. Each series consisted of ten trials of a standardized behavioural task (total 60 trials) involving holding and splitting a flat-faced tablet (8mm, 180mg) placed on a bite force transducer with the anterior teeth. The hold and split forces along with the electromyographic (EMG) activity of the left and right masseter (MAL and MAR), left anterior temporalis (TAL) and digastric (DIG) muscles were recorded. A series (ten trials) of natural biting tasks was also performed before and after the six series of the behavioural task. RESULTS The mean hold force (P<0.001) but not the mean split force (P=0.590) showed significant effect of number of series. No significant effect of series was seen on the variability of hold and split force and the EMG activity except for the variability of EMG activity for MAL during the hold phase (P=0.021) and DIG during the split phase (P<0.001). The behavioural task had no effect on the EMG activity of the natural biting task. CONCLUSION There was no evident optimization of jaw motor function in terms of reduction in the variability of bite force values and muscle activity, when this simple task was repeated up to sixty times in participants with normal intact periodontium.

The patient undergoing implant therapy. Summary and consensus statements. The 4th EAO Consensus Conference 2015

INTRODUCTION The assignment for this working group was to update the existing knowledge regarding factors considered being of special relevance for the patient undergoing implant therapy. This included areas where conflicting opinions exists since long or recently has been expressed, like the role of antibiotic prophylaxis in dental implant surgery and peri-implantitis. Also areas with growing interest and concern such as patient-reported outcome measures (PROMs) and health-economy was included in this review. MATERIALS AND METHODS The literature in the respective areas of interest (antibiotic prophylaxis, peri-implantitis, patient-reported outcome measurements and health-economic aspects) was searched using different strategies for the different papers. Search strategies ranged from a complex systematic review to systematic- and narrative reviews, depending on subject and available literature. All collected material was critically reviewed. Four manuscripts were subsequently presented for group analysis and discussion and plenum discussions and concensus approval. The selected areas were considered to be of key importance and relevance for the patient undergoing implant therapy. RESULTS The results and conclusions of the review process are presented in the respective papers. The groups conclusions, identified knowledge gaps, directions for future research and concensus statements are presented in this article. The following reviews were available for group discussions and the foundation for subsequent plenary sessions: Lund B, Hultin M, Tranaeus S, Naimi-Akbar A, Klinge B. (2015) Perioperative antibiotics in conjunction with dental implant placement. A complex systematic review. Renvert S & Quirynen M. (2015) Risk indicators for peri-implantitis. A narrative review. De Bruyn H, Raes S, Matthys C, Cosyn J. (2015) The current use of patient centered/reported outcomes in implant dentistry. A systematic review. Beikler T & Flemmig T.F. (2015) Economic evaluation of implant-supported prostheses. A narrative review.

Comparison of fatigue resistance and failure modes between metal-ceramic and all-ceramic crowns by cyclic loading in water

OBJECTIVES To compare fatigue resistance and fracture mode of metal-ceramic crowns with all-ceramic crowns containing yttria tetragonal zirconia polycrystal (Y-TZP) frameworks under compressive cycling loading in water. METHODS Twenty specimens of ivory were randomized and individually prepared to receive anatomically shaped metal-ceramic (n=10) or veneered Y-TZP all-ceramic crowns (n=10). All steps in production were equivalent to clinical situations. Resistance to fatigue fracture was tested under compressive cyclic loading using a universal testing machine, with a loading frequency of 12Hz using a spherical tungsten carbide indenter (6mm diameter) in distilled water. The maximum compressive load was increased as the number of cycles increased (600,000 cycles at 400N, 200,000 cycles at 600 N, 200,000 cycles at 800 N and 200,000 cycles at 1000 N). The specimens were inspected after each loading sequence for initial failures such as infractions. Final failure was considered as any loss of material which automatically ended the test and the number of cycles until final failure was recorded. Fractographic analysis of the fractured specimens was performed with scanning electron microscopy (SEM). RESULTS The two types of crowns exhibit similar fatigue resistance (P=0.87) to compressive cycling loading under wet conditions. The failure modes as observed with SEM were similar in the two groups and were found in the veneer ceramic, except that three veneered Y-TZP all-ceramic crowns displayed a complete framework fracture. CONCLUSIONS Within the limitation of this study using simulated oral masticatory function, the results revealed that the fatigue resistance was similar for the two crown types. CLINICAL SIGNIFICANCE In this study metal-ceramic crowns and veneered Y-TZP all-ceramic crowns showed similar fracture resistance to compressive cycling loading in water. The test conditions were simulating clinical conditions. Thus, the result may predict the long-term clinical performance of these types of crowns.