Incidence and association of root fractures after prosthetic treatment

Survival time analysis of remaining teeth following replacement of unilateral free-end missing teeth: A comparison between fixed implant-supported prostheses and removable partial dentures

OBJECTIVES

This retrospective study aimed to investigate the differences in tooth loss rate between fixed implant-supported prostheses (FISPs) and removable partial dentures (RPDs) in cases of unilateral free-end missing teeth.

MATERIALS AND METHODS

The data of 324 patients who underwent treatment with FISPs or RPDs for unilateral free-end missing teeth and satisfied the applicable criteria, were evaluated (47 in the FISPs group and 277 in the RPDs group). After propensity score (PS) matching, which was used to extract patients with similar background factors related to prosthetic selection at baseline, survival time analyses were performed with tooth loss as the endpoint. The adjusted variables were age, sex, number of restored teeth, periodontal status, and the practicing dentist's experience in years. The remaining teeth were classified into subcategories in relation to the missing molars.

RESULTS

Overall, 58 patients (29 in each group) selected by PS matching were evaluated in the final analysis. The total number of lost teeth was 35 (FISPs group: n = 10; RPDs group: n = 25). The mean (±SD) period to tooth loss and the 10-year survival rates in the FISPs and RPDs groups were 51.6 (±30.1) months and 42.3 (±29.7) months, 70.5% and 16.4%, respectively. The log-rank test showed that significantly longer survival time in FISPs compared with RPDs.

CONCLUSIONS

After adjustments for confounding factors using PS matching, replacing unilateral free-end missing teeth with FISPs may exhibit a lower tooth loss rate in adjacent and contralateral teeth compared to replacing with RPDs.

Radiographic predictive factors for 10-year survival of removable partial denture abutment teeth: Alveolar bone level and density

PURPOSE

To determine postoperative periodontal and radiographic factors that predict the survival rates of abutments of removable partial dentures (RPDs).

METHODS

Patients who wore RPDs for > 10 years and received supportive periodontal therapy were included. Periodontal examinations and radiographic assessments were conducted on 83 abutment teeth in 35 patients at baseline, and five years after RPD insertion. In addition to conventional factors, such as tooth mobility at 5 years, radiographic factors, such as the crown-root ratio (ΔCR ratio) and gray-level changes reflecting changes in alveolar bone density (ΔABD), were evaluated. The impact of the covariables on the 10-year survival of abutment teeth was estimated using a multivariate Cox regression model, considering multicollinearity.

RESULTS

Patients were classified as having A2-B2 (45.7%) and B3-C2 (54.3%) tooth loss, according to the Eichner classification. A probing depth ≥ 4 mm, tooth mobility ≥ grade 1, and CR ratio ≥ 1 were found in 30.1%, 33.7%, and 51.8% of abutment teeth, respectively. The 10-year survival rate of abutment teeth was 86.7%. Multivariate analysis showed that the 10-year survival of abutment teeth was significantly associated with root canal treatment (P = 0.045, hazard ratio [HR] = 1.23), the 5-year ΔCR ratio (P = 0.022, HR = 3.20), and ΔABD on the edentulous side of the abutment teeth (P = 0.047, HR = 1.08).

CONCLUSIONS

In addition to root canal treatment, changes in the CR ratio and radiographic alveolar bone density at five years predicted the long-term survival rate of RPD abutments.

Is the Diagnosis of Generalized Stage IV (Severe) Periodontitis Compatible with the Survival of Extended Stabilizing Prosthetic Restorations? A Medium-Term Retrospective Study

The aim of the study was to identify the most relevant patient-related factors directly involved (alone or in combinations) in the long-term survival and functionality of the abutment teeth of extensive stabilizing bridges and removable prosthesis, in patients treated for Stage IV periodontitis, adhering to SPT over a period of at least 5 years. Seventy-six patients treated between 2000-2022, rehabilitated with FDPs and RDPs, adhering to SPT for at least 5 years were included. Patient-related factors influencing retention of RDPs and FDP, survival rates in regular (RCs) and irregular compliers (ICs), and incidence of biological and technical complications were assessed. During a follow-up of 69 months, from 57 patients with FDPs and 19 patients with RDPs, 39 (51.32%) were ICs, while 37 (48.68%) were RCs. An overall statistically significant association (p = 0.04) was identified between biological complications and the type of prostheses. The RDP patients had more complications than FDP patients. In 5.26% of the RDP patients, root caries were identified, and 10.53% were diagnosed with a periapical (endodontic) lesion, while 3.51% of the FDPS patients presented root caries. In five (6.57%) cases, abutment loss resulted in the loss of the prosthesis. Statistically significant correlations were observed between systemic diseases and tooth loss, and between type of tooth lost and the reason for tooth loss, irrespective of the type of prosthesis. A total of 66.67% of the lost incisors, 85.71% of the lost premolars, and 88.89% of the lost molars occurred due to periodontal causes. Furthermore, 93% of the FDPs and RDPs were still in place and in function.

In vivo detection of vertical root fractures in endodontically treated teeth: Accuracy of cone-beam computed tomography and assessment of potential predictor variables

Background

This study aimed: (a) to determine the diagnostic performance of cone-beam computed tomography (CBCT) for detection of vertical root fractures (VRFs); (b) to evaluate the predictive value of diagnostic criteria regarding the definition of VRFs; and (c) to examine the robustness of the association of patient-, tooth-, and treatment-related variables with VRFs.

Material and Methods

130 root-filled teeth with signs/symptoms of VRFs underwent clinical and CBCT assessments. Definite diagnosis of VRF was confirmed by endodontic microsurgical (EMS) exploration. Determination of diagnostic performance of CBCT was based on standard algorithms derived from two-way contingency table analysis. Predictive value of diagnostic criteria and the association between predictor variables with VRFs were analyzed using logistic regression models.

Results

VRFs were detected during EMS in 50% of the teeth. Based on the finding of fracture lines on CBCT scans, sensitivity, specificity, and accuracy were 86.2%, 13.8%, and 50%, respectively. Teeth having more than three diagnostic criteria present had significant higher odds for VRF diagnosis. After logistic regression analysis, parafunctional habits, one-canal roots, excessive root canal enlargement, and absence of intra-radicular posts remained as robust predictor variables of VRFs.

Conclusions

Although the sensitivity of CBCT for VRFs detection is high, the risk of false-positive results related to its low specificity makes that all suspected cases must be confirmed by surgical exploration. VRFs cannot be reliably diagnosed by isolated clinical signs/symptoms; instead those teeth possessing more than three diagnostic criteria might be considered practically pathognomonic. The parafunctional habits, one-canal roots, excessive root canal enlargement, and the absence of intra-radicular posts may act strongly/independently for the occurrence of VRFs in endodontically treated teeth.

Key words:Cone-beam computed tomography, diagnostic accuracy, diagnostic surgery, predictor variables, root canal treatment, vertical root fracture.

Retentive Characteristics of a Polyetheretherketone Post-Core Restoration with Polyvinylsiloxane Attachments

A new application of a polyetheretherketone (PEEK) post-core restoration combined with polyvinylsiloxane (PVS) attachments was proposed and substantiated. This study aimed to evaluate retentive characteristics of the PEEK post-core restoration with PVS attachment systems. Specimens with PVS attachments were fabricated to evaluate retention force during 10,000 cyclic dislodgements. Additionally, the retention forces of PVS attachments with three different values of Shore hardness were further measured before and after aging treatments. The results of cyclic dislodgement test indicated a strong negative linear relationship between the cyclic times and retention force (p < 0.0001, r = −0.957). Furthermore, the retention forces of the PVS were significantly improved with Shore hardness increased, which was also affected by the aging treatment (F (2, 138) = 10.95, p < 0.0001). Therefore, the PEEK post-core restoration with PVS attachments exhibited the favorable retention force, which could be a promising alternative for dental prostheses.

Impact of Removable Partial Denture Type on Patient Satisfaction and Abutment Survival Rate-RCT

BACKGROUND:

Patient’s satisfaction and the preservation of abutments is the most important outcomes that the clinician seeks during fabrication of any dental treatment, especially when it is concerned with removable prosthodontic rehabilitation.

AIM:

The present study evaluates three different Removable Partial Denture (RPD) types restoring mandibular class II modification I edentulous cases with regards to patient’s satisfaction and abutments survival.

METHODS:

Forty-two partially edentulous patients were divided into three groups (Group I rehabilitated with Vitallium RPD, Group II rehabilitated with Vitallium RPD where the modification area restored with the surveyed bridge, Group III rehabilitated with Thermopress RPD). The patients were followed up for twenty-four months. Using a questionnaire, prosthodontic maintenance required was documented at the delivery and after 3 months.

RESULTS:

There was a significant difference regarding patient satisfaction for group III (P-value <0.05) while for groups I and II there was a non-significant difference (P-value >0.05). Regarding the survival rate, there was a non-significant difference between the three groups (P-value >0.05) at the end of twenty-four months of follow up.

CONCLUSION:

Patient satisfaction and abutment survival were better with Thermopress RPD than conventional Vitallium RPD or Vitallium RPD with a surveyed bridge restoring the modification area. Although a non-statistically significant difference was found in the survival rate of abutments between groups, a clinically important result was revealed as no abutments failures were reported in the Thermopress group.

Assessment of extracting molars and premolars after root canal treatment: A retrospective study

Background

The loss of dentition after root canal treatment is a multifactorial entity which might differ between different teeth. The extraction can be more critical, as well as the rehabilitation options.

Aim

To analyze if the etiology of extracting root canal treated teeth is different between premolars and molars.

Materials and methods

The study included a total of 403 cases with non-surgical root canal therapy (NSRCT) and crown coverage that was referred to the oral surgery clinic for extraction. Tooth type, patient’s age, gender, time since treatment completion, and the reason for extractions were recorded and analyzed.

Results

The most frequently extracted teeth were molars (55.6%), followed by premolars (30.3%) and anterior teeth (14.1%). The reasons for extraction were subgingival decay (SGD) (62.5%), vertical root fractures (VRF) (25.3%), and patient demands after uncomfortableabscess discharge (12.2%). Most of the teeth survived between 13 and 36 months after NSRCT. The statistical power of 0.92 was demonstrated, and a P-value of less than 0.05 presented significant correlations.

Conclusion

Molars were extractedafter NSRCT due to SGD followed by premolars, which were extracted due to VRF. Special care should be taken while planning NSRCT treatment for molars, in particular, with emphasis on the importance of oral hygiene and follow-up visits.

Bonding effectiveness and multi-interfacial characterization of two direct buildup resin core systems bonded to post-space dentin

OBJECTIVES

The aim of the present study was to evaluate the bonding effectiveness of two resin core buildup systems using conventional methods in the field of adhesive dentistry and a new non-destructive method.

MATERIALS AND METHODS

Twenty-four single-rooted human teeth were built up with dual-cure one-step self-etch adhesive and composite systems (SY1: Clearfil DC bond and Clearfil DC core automix, SY2: Clearfil bond SE one and Clearfil DC core automix one). The prepared samples were sectioned into approximately 1 × 1-mm-thick beams and subjected to micro-tensile bond strength (μTBS) testing (n = 24). The fractured beams after μTBS testing were analyzed by SEM and energy-dispersive X-ray (EDX) spectrometry. The three teeth filled with each resin core system were sectioned and embedded in epoxy resin to observe the dentin-bonding interface under TEM (n = 6). Moreover, three of each resin core-filled teeth without any processing were examined using μCT (n = 6).

RESULTS

Two-way ANOVA revealed that the two factors "root region" (p < 0.001, F = 15.22) and "system" (SY1 < SY2; p < 0.001, F = 22.52) had a significant influence. The μTBS gradually decreased from the coronal side to the apical side of the root canal. Morphological evaluation revealed that SY2 was superior in terms of resin curing at the apical side. μCT non-destructive evaluation clearly revealed gap formation in SY1.

CONCLUSION

SY2, which included a new light-independent catalyst, showed better bonding effectiveness and adhesive interface to dentin compared to that of SY1.

CLINICAL RELEVANCE

The new catalyst, which is activated by contact with adhesive and resin composite, can be used for resin core buildup restorations.

Nondestructive observation of teeth post core-space using optical coherence tomography: comparison with microcomputed tomography and live images

No previous reports have observed inside the root canal using both optical coherence tomography (OCT) and x-ray microcomputed tomography (μCT) for the same sample. The purpose of this study was to clarify both OCT and μCT image properties from observations of the same root canal after resin core build-up treatment. As OCT allows real-time observation of samples, gap formation may be able to be shown in real time. A dual-cure, one-step, self-etch adhesive system bonding agent, and dual-cure resin composite core material were used in root canals in accordance with instructions from the manufacturer. The resulting OCT images were superior for identifying gap formation at the interface, while μCT images were better to grasp the tooth form. Continuous tomographic images from real-time OCT observation allowed successful construction of a video of the resin core build-up procedure. After 10 to 12 s of light curing, a gap with a clear new signal occurred at the root-core material interface, proceeding from the coronal side (6 mm from the cemento-enamel junction) to the apical side of the root.

Effect of tapering internal coronal walls on fracture resistance of anterior teeth treated with cast post and core: In vitro study

When fabricating indirect post and core, internal coronal walls are tapered to remove undercuts and allow a better adaptation. To evaluate the fracture strength of anterior tooth reconstructed with post and core and crowned, with two different taper of internal coronal walls, 6° and 30° to the long axis, two groups of 30 clear plastic analogues simulating endodontically treated maxillary central incisors were prepared. The analogues crowned were subjected to a compressive load with a 1-kN cell at a crosshead speed of 0.05 mm/min at 130° to the long axis until fracture occurred. Data were analyzed by Lillifors and Mann–Whitney tests. Mean failure loads for the groups were as follows: group I 1038.69 N (standard deviation ±243.52 N) and group II 1231.86 N (standard deviation ±368.76 N). Statistical tests showed significant difference between groups (p = 0.0010 < 0.01). Increasing the taper of internal coronal walls appears to enhance the fracture resistance of anterior maxillary teeth post and core reconstructed.

Comparative cross-sectional study of masticatory performance and mastication predominance for patients with missing posterior teeth

PURPOSE

Missing posterior teeth can decrease masticatory function and cause horizontal mastication deviation, i.e., mastication predominance. Mastication predominance may lead to abnormal tooth attrition and temporomandibular disorders. This study evaluated masticatory performance and mastication predominance in patients with missing posterior teeth to investigate effects of missing posterior teeth on masticatory performance and mastication predominance.

METHODS

Thirty volunteers with normal dentition (control group), 30 patients with unilateral missing posterior teeth (unilateral group), and 23 patients with bilateral missing posterior teeth (bilateral group) participated. Gummy jellies were used to evaluate participants' masticatory performance, and electromyography was used to assess the degree of mastication predominance. Chewing gums, gummy jellies, and peanuts were used as foods of various hardnesses for evaluating mastication predominance.

RESULTS

Compared with the control group, masticatory performance did not differ in the unilateral group but was significantly decreased in the bilateral group. With chewing gum and gummy jellies, the degree of mastication predominance was significantly increased in both unilateral and bilateral groups than the control group. With peanuts, the degree of mastication predominance was significantly increased in the unilateral group than the control group.

CONCLUSIONS

Although masticatory performance was not decreased in the unilateral group, the degree of mastication predominance was increased. Decreased masticatory performance was observed in the bilateral group, and for foods with normal hardness and soft foods, the degree of mastication predominance was increased. These results suggested that mastication predominance should be considered in the recovery of masticatory performance in patients with missing posterior teeth.

Nondestructive observation of teeth post core space using optical coherence tomography: a pilot study

Coronal tooth lesions, such as caries, enamel cracking, and composite resin restoration cavities, have been observed by optical coherence tomography (OCT). This pilot study was performed to verify whether OCT could reveal details of root canals filled with resin core build-up. A dual-cure, one-step, self-etch adhesive system-bonding agent (Clearfil Bond SE ONE, Kuraray Noritake Dental) and dual-cure resin composite core material (Clearfil DC Core Automix ONE, Kuraray Noritake Dental) were used according to the manufacturer's instructions in root canals. OCT was performed at three stages of the core build-up: after the post space preparation, after bonding application, and after resin core fabrication. The cementum was removed in the cementum absent group and the root was left untreated in the cementum present group. Bubbles were observed in the resin cores and gaps formed between the resin core and dentin. In the cementum absent group, the internal structure of the root could be visualized clearly compared with the cementum present group. The root internal structure could be observed by OCT and the image became clearer when cementum was removed.

Comparative diagnostic yield of cone beam CT reconstruction using various software programs on the detection of vertical root fractures

OBJECTIVES

To evaluate the effect on diagnostic yield in the detection of experimentally induced vertical root fractures on cone beam CT images using four dental software program.

METHODS

190 single-rooted extracted human teeth were divided into three groups according to the pulp canal status: unrestored (UR), filled with gutta-percha (GP) and restored with a metallic custom post (Post). One-half of the sample of each group was artificially fractured and the segments repositioned. All teeth were scanned on a cone beam CT device at 0.2 mm nominal voxel resolution (i-CAT Platinum; Imaging Sciences International, Hatfield, PA). The data were exported as digital imaging and communications in medicine files and imported into Dolphin Imaging & Management Solutions, v. 11.5 (Patterson Dental Supply Inc., St Paul, MN), InVivoDental, v. 5.0 (Anatomage Inc., San Jose, CA) and Kodak Dental Imaging Software 3D module, v. 2.1.11 (Carestream Health Inc., Rochester, NY) software. Cross-sectional images in the acquisition (using Xoran CAT™, v. 3.0.34 software; Xoran Technologies, Ann Arbor, MI) and additional software were presented to three calibrated oral radiologists who rated the presence or absence of root fracture on a five-point scale. Receiver operating characteristic analysis was performed, and treatment comparisons compared by analysis of variance and pairwise comparisons were performed using Tukey's test at an a priori value of α < 0.05%.

RESULTS

All dental software performed equally at detecting fractures. Fractures were significantly more difficult to detect when posts were present.

CONCLUSIONS

The diagnosis of root fracture is software-independent. The presence of an intracanal metallic post significantly decreases the detection of artificially created root fractures.