Journal of prosthodontic research最新文献

Patients: A case series of five patients (mean age, 77.0 years) with complaints of nocturnal xerostomia were subjected to occlusal appliance treatment with a reservoir of moisturizing gel during the night. An occlusal appliance covers the dental arch and hard palate, providing space in the midline of the hard palate to hold the moisturizing gel. Sleepiness was assessed using the Epworth Sleepiness Scale (ESS), and sleep quality was assessed using the Japanese version of the Pittsburgh Sleep Questionnaire (PSQI-J) before and after treatment. The total PSQI-J scores decreased in all patients after treatment. The ESS score, sleep time, and sleep efficiency improved or remained unchanged and none of the patients' symptoms worsened.

Discussion: This study demonstrated the efficacy of occlusal appliance treatment in patients with dry mouth in improving self-reported sleep quality. Patients included those with nocturnal xerostomia and poor sleep quality on the PSQI-J. Treatment with xerostomia resulted in improved sleep quality, as assessed by the decrease in PSQI-J scores.

Conclusions: This case series suggests that sleep quality may be worse in patients with xerostomia, and that treatment for nocturnal xerostomia using occlusal appliances may improve sleep quality.

Purpose: To assess the radiographic outcomes, complications, and implant survival rates of advanced platelet-rich fibrin versus xenografts in hydraulic sinus floor elevation.

Methods: In this randomized trial, 40 patients with 46 implants were divided into two groups: a test group (advanced platelet-rich fibrin alone) and a control group (xenograft alone). The key outcome measures included bone regeneration, implant survival, and complications.

Results: Both groups achieved 100% implant survival. One case of maxillary sinus infection occurred in the control group after surgery. There was no significant difference in bone regeneration between the two groups at 6 months post-surgery and 12 months post-load (P > 0.05). The residual bone height and sinus width at the apex of the implant were significant negative predictors of bone regeneration (P < 0.05), whereas the presence of adjacent teeth was a significant positive predictor (P < 0.05).

Conclusions: Both advanced platelet-rich fibrin and xenografts effectively enhanced bone growth at sinus floor elevation, achieving high implant survival rates over one year. Advanced platelet-rich fibrin alone may be a viable xenograft alternative, necessitating further long-term studies to confirm its efficacy. The study was registered in the Chinese Clinical Trial Registry (http://www.chictr.org.cn/) with the registration number ChiCTR2100042060. This clinical trial was not registered before participant recruitment or randomization.

Purpose: This study evaluated the effects of screw preload loss on three implant systems, both in silico and in vitro.

Methods: Three finite element analysis (FEA) models of implant restorations were created using bone-level (BL, 4.8×12 mm; BLX, 4.5×12 mm) and tissue-level (TL, 4.8×12 mm) implant systems. The screws in each group were subjected to preloads of 100 N and 200 N, with an additional 130 N load applied to the crown tops. An in vitro study of the principal strain was conducted using digital image correlation (DIC) under the same conditions as for the FEA models. The results were evaluated for von Mises stress, principal strain, and sensitivity index.

Results: During loading, the highest stress levels were observed in the implants and screws. In the BL group, the screws experienced the highest von Mises stress at 466.04 MPa and 795.26 MPa in the 100 N and 200 N groups, respectively. The BLX group showed the highest von Mises stress at 439.33 MPa and 780.88 MPa in the implants in the 100 N and 200 N groups. Sensitivity analysis revealed that the screws and abutments in the TL group were significantly more affected by the preload changes.

Conclusions: The abutment in the TL group was particularly sensitive to preload changes compared with those in the BL and BLX groups. Variations in the preload significantly affect the stress distribution in implants and screws. Maintaining screw preload stability under loading is crucial in clinical practice to prevent mechanical failure.

Purpose: This network meta-analysis (NMA) of randomized controlled trials (RCTs) aimed to identify effective initial conservative treatment strategies for patients with temporomandibular joint disorders (TMD).

Study selection: RCTs comparing treatment options for TMD published between January 2000 and July 2021 were retrieved from the databases of PubMed and Embase via a comprehensive electronic search. Patients diagnosed with myalgia (muscle pain) or arthralgia (joint pain) according to pain-related Diagnostic Criteria for Temporomandibular Disorders (DC/TMD) and the Research Diagnostic Criteria for Temporomandibular Disorders (RDC/TMD) were eligible for inclusion. Twelve treatment options and a placebo were included in the mutual comparisons. The risk of bias was assessed using Risk of Bias 2.0. Forest plots of direct comparisons between individual studies were created using MetaInsight. NMA was performed using R statistical software (netmeta).

Results: Twenty-four RCTs involving 1336 patients assessing pain and 12 RCTs involving 614 patients assessing maximal mouth opening were identified. Low-level laser therapy (standard mean difference [SMD]: -2.12, 95% confidence interval [CI]: -3.18, -1.06), self-exercise (SMD: -1.51, 95% CI: -2.82, -0.2), and stabilization splints (SMD: -1.16, 95% CI: -2.02, -0.29) were effective in improving pain; however, the certainty of evidence was very low. Self-exercise (SMD: 0.71, 95% CI: -0.58, 2.01), stabilization splints (SMD: 0.65, 95% CI: -0.09, 1.39), and low-level laser therapy (SMD: 0.63, 95% CI: -0.34, 1.6) were effective in improving maximal mouth opening; however, the certainty of evidence was very low.

Conclusions: Stabilization splints, self-exercise, and low-level laser therapy may be effective in the initial treatment of TMD.

Purpose: Additive cast-fabrication has yet to be used as commonly in implant prosthodontics as conventional methods. This review aimed to investigate the accuracy of additive cast-fabrication in implant prosthodontics.

Study selection: The study protocol was registered in the PROSPERO database (CRD42022374972). Reporting was based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines, following the Cochrane Handbook. Two-arm interventional studies that matched the PICO were included (Population: dental typodonts with implants, Intervention: additive cast-fabrication, Comparator: conventional cast-fabrication, Outcome: positional deviations). A systematic search was conducted in three databases: PubMed (MEDLINE), EMBASE, and the Cochrane Library (CENTRAL).

Results: Seven papers were included in the analysis of horizontal, vertical, and root mean square (RMS) deviations. No significant differences were observed between groups. The overall vertical mean deviation of the intervention group was -4.15 µm [-24.88; 16.57], and the pooled mean absolute deviation was 22.43 µm [8.33; 36.54]. In the control group, these values were 19.67 µm [-32.71; 72.04] and 24.62 µm [0.00; 59.42], respectively. The overall horizontal mean deviation in the intervention group was 21.29 µm [-77.10; 119.68], and the pooled mean absolute deviation was 26.96 µm [0.00; 70.81]. In the control group, the overall mean was 1.45 µm [-32.26; 35.15] and the pooled mean absolute deviation was 25.05 µm [9.08; 41.01]. The mean RMS was only slightly larger in the intervention group, with the value of 14.74 µm [-107.26; 136.74].

Conclusions: Additive cast-fabrication is as accurate as the conventional method for the position of implant analogs.

Purpose: This study aimed to compare the deviation of hypermobile teeth in partially edentulous dental arches during impression taking using digital and conventional techniques.

Methods: A partially edentulous mandibular model with three target hypermobile teeth (including the left first premolar, #34; left second molar, #37; and right first premolar, #44), was used as the simulation model. After reference data were acquired using a desktop scanner, impressions of the simulation model were obtained using a digital intraoral scanner (IOS) and two conventional techniques (hydrocolloid material with a stock tray and silicone material with a custom tray as impression data (n=12/group). The three-dimensional accuracy (root mean square value) and two-dimensional accuracy (mesiodistal and buccolingual displacements) of the target teeth in each impression dataset were calculated based on the reference data. The comparison among three impression techniques was statistically performed using the Kruskal-Wallis test (α=0.05).

Results: For #34 and #44, the three- and two-dimensional accuracies of the impressions fabricated through data acquired through digital scanning (digital impression) were significantly superior to those of the hydrocolloid impression (P < 0.05), whereas no significant difference was found between the digital and silicone impressions. For #37, no significant difference in the accuracy of the impression data for the target teeth was observed among the three impression techniques.

Conclusions: Digital impression acquiring using an IOS is recommended over using a conventional hydrocolloid impression to prevent the deviation of hypermobile teeth in partially edentulous dental arches. Hypermobile tooth deviation in digital impression data depends on the tooth location.

Purpose: The innate immune response, particularly the reaction of polymorphonuclear neutrophils (PMNs), is crucial in shaping the outcomes of chronic inflammation, fibrosis, or osseointegration following biomaterial implantation. Peri-implantitis or peri-mucositis, inflammatory conditions linked to dental implants, pose a significant threat to implant success. We developed a single-cell analysis approach using a murine model to assess the immune response to implant materials, offering a practical screening tool for potential dental implants.

Methods: We performed bioinformatics analysis and established a peri-implant inflammation model by inserting two titanium implants into the maxillary region, to examine the immune response.

Results: Bioinformatics analysis revealed that titanium implants triggered a host immune response, primarily mediated by PMNs. In the in vivo experiments, we observed a rapid PMN-mediated response, with increased infiltration around the implants and on the implant surface by day 3. Remarkably, PMN attachment to the implants persisted for 7 days, resembling the immune profiles seen in human implant-mediated inflammation.

Conclusions: Our findings indicate that persistent attachment of the short-living PMNs to titanium implants can serve as an indicator or traits of peri-implant inflammation. Therefore, analyzing gingival tissue at the single-cell level could be a useful tool for evaluating the biocompatibility of candidate dental implants.

Purpose: To compare the effectiveness of keratinized mucosa (KM) augmentation with different techniques for the treatment of dental implants based on risk assessment.

Methods: Thirty-nine patients who underwent KM augmentation at implant sites in the posterior mandible were included. Three techniques were used based on anatomy-guided risk assessment: an apically positioned flap (APF) alone, an APF plus a free gingival graft (APF plus FGG), and an APF plus a collagen matrix (APF plus CM). Clinically effective KM augmentation was defined as remaining KM ≥ 2 mm after the intervention. The effective rate, implant/prosthesis survival rates, and bone/soft tissue parameters were analyzed. The correlation between local anatomical characteristics and different techniques was also determined. The associations between the effectiveness of KM augmentation and related factors were analyzed using a linear model.

Results: Overall, 74 sites received KM augmentation in the posterior mandible, for an effective rate of 94.6% at the 1-year follow-up and 93.2% at the 5-year follow-up. The KM width in the APF plus FGG group (3.85 ± 1.22 mm) was greater than that in the APF alone (3.05 ± 0.90 mm) (P = 0.016) and APF plus CM (3.21 ± 1.17 mm) groups (P = 0.038) at 5 years post-surgery. There was no significant difference in the effective/ineffective outcomes at the 1-year or 5-year follow-up among the three groups.

Conclusions: Comparable effective outcomes were achieved with three KM augmentation techniques following the decision-making criterion based on risk assessment.

Purpose: The lack of occlusal support reportedly reduces cognitive function; however, the underlying mechanisms remain unclear. The locus coeruleus, which is located adjacent to the trigeminal mesencephalic nucleus, secretes noradrenaline throughout the brain. In this study, we evaluated the effects of noradrenaline in the hippocampus and cerebral cortex on cognitive decline following tooth extraction in rats.

Methods: We performed passive avoidance experiments on male Wistar rats with extracted maxillary molars and determined the neuron density in the locus coeruleus and trigeminal mesencephalic nucleus using immunostaining and Nissl staining, respectively. We also assessed noradrenaline concentrations in the hippocampus and cerebral cortex using enzyme-linked immunosorbent assay.

Results: In the passive avoidance experiment, the latency in the bright compartment was significantly shorter (P < 0.05) in the extraction group than in the control group. The numbers of cells in the locus coeruleus and trigeminal nucleus were significantly lower (P < 0.05) in the extraction group compared to those in the control group. The noradrenaline levels in the hippocampus and cerebral cortex were also significantly lower (P < 0.05) in the extraction group than those in the control group.

Conclusions: The lack of occlusal support associated with tooth extraction reduces the number of cells in the trigeminal mesencephalic nucleus and locus coeruleus, which may reduce the supply of noradrenaline to the cerebral cortex and hippocampus, leading to a decline in cognitive function.

Purpose: This in vitro study investigated the effect of build orientation on the wear resistance and hardness of denture teeth fabricated using digital light processing (DLP) compared to other denture tooth materials.

Methods: Disc-shaped specimens were prepared using denture tooth monomers and DLP devices in three build orientations: 0°, 45°, and 90°. Specimens of the same shape were fabricated using denture tooth materials for subtractive manufacturing, commercially available polymethylmethacrylate (PMMA) resin, and composite resin. The wear resistance was evaluated as the wear volume loss after 50,000 wear cycles using a ball-on-disc wear device in water for two-body wear and poppy seed slurry for three-body wear. The Vickers hardness values of the materials were measured. Two-way and one-way analyses of variance were performed for wear resistance and hardness, respectively, followed by Tukey's honest significance test.

Results: The interaction between the denture tooth resins and maximum wear volume was significant (P < 0.01). The 0° build orientation exhibited the lowest wear volume in the three-body wear test and the highest hardness among the three build orientations. The 0° DLP-fabricated specimens demonstrated significantly less wear volume than that of the PMMA specimens and a wear volume comparable to that of the milled specimens. However, the 0° DLP-fabricated specimens showed significantly lower hardness than that of the milled and PMMA specimens. The composite resin specimens exhibited the highest wear resistance and hardness.

Conclusions: A 0° build orientation is recommended for DLP-fabricated denture teeth compared to 45° and 90° orientations to achieve greater wear resistance and hardness.