Journal of prosthodontic research最新文献

Purpose: Acute stroke often leads to dysphagia. In the oral stage of dysphagia, there is a potential for immediate benefit from using a palatal augmentation prosthesis (PAP). We investigated whether our quickly fabricated, simple, and expedited version of PAP would result in an immediate improvement in swallowing function after an acute stroke.

Methods: We analyzed the records of stroke patients that were hospitalized between October 2019 and March 2022 and met the following criteria: they had a rehabilitation prescription and had paralysis of facial or hypoglossal nerves and either repeated salivary swallowing test ≤2 times or modified water swallow test ≤3, they were fasting, were within 3 weeks of onset, and had a simple PAP made for them. Outcomes included with/without PAP, maximum tongue pressure, repeated salivary swallowing test, and modified water swallow test on the day after starting to wear PAP was started. In addition, within one week, a videofluoroscopic examination was performed to measure the oral transit time, pharyngeal transit time, and penetration aspiration scale. Statistical analyses were performed using Wilcoxon signed-rank tests. Statistical significance was set at P < 0.05.

Results: Fifteen patients met the inclusion criteria and were included in this study. The mean age of the subjects was 76.9 ± 9.0 years. The use of PAP significantly increased maximum tongue pressure (P < 0.0001*) and shortened oral transit time (P < 0.0091*). There were no significant differences among the other items.

Conclusions: Simple PAP immediately increased the maximum tongue pressure and improved swallowing function during the oral stage.

Purpose: Marginal bone loss (MBL) occurs in the periapical cervical bone after dental implant placement and abutment connection. MBL may not result in peri-implantitis; however, it is always accompanied by MBL. Recent studies have demonstrated that early MBL is a predictor of peri-implantitis. In this narrative review, we aimed to provide an evidence base for recommended treatment strategies for clinicians to prevent MBL.

Study selection: We reviewed the recent literature and performed a narrative synthesis of the evidence, focusing on available systematic reviews and meta-analyses of implant marginal bone resorption.

Results: The available evidence indicates that certain biological, material, and technical factors can influence MBL and consequently dictate the risk of developing peri-implant disease in later years. The order of the impact of the strength of each factor is unknown. Current recommendations to prevent MBL include controlling patients' smoking and hemoglobin A1c levels to sufficiently low levels before surgery and throughout their lifetime. Regarding the material, a platform-switching, conical-connecting implant system, and an abutment with a height of at least 2 mm should be selected. Placement should be performed using techniques that ensure sufficient soft tissue (keratinized gingival width > 2 mm, supracrestal tissue height > 3 mm), and non-undersized preparations in the cortical bone should be made with connected concave abutments during primary or secondary surgery. Patients should receive supportive peri-implant therapy during maintenance.

Conclusions: MBL development is multifactorial and can be reduced by considering the biological, material, and technical factors.

Purpose: The present clinical study aimed to investigate the load exerted on abutment teeth in patients with distal extension edentulism, with and without a removable partial denture (RPD).

Methods: A total of 55 volunteers with distal extension edentulism who were fitted with an RPD participated in the present study. Occlusal force was measured by having the patients bite down on an occlusal force measuring sheet, and the occlusal forces on both the abutment teeth and the entire dentition with and without the RPD were compared using the Wilcoxon signed-rank test (P < 0.05). The occlusal forces on the abutment and non-abutment teeth were also compared.

Results: The median total occlusal force with the RPD in place was significantly greater than that without the RPD, while the median occlusal force on the abutment teeth without the RPD in place was significantly greater than that on the abutment teeth with the RPD. The occlusal forces on the abutment teeth were significantly greater than those on the non-abutment teeth.

Conclusions: Within the limitations of the present study, we found that the occlusal forces were greater on the abutment than the non-abutment teeth, and that RPDs may reduce the occlusal forces on abutment teeth.

Purpose: Poor contour of the implant restoration causes plaque accumulation and increases the risk of peri-implantitis. This study aimed to investigate whether the prosthodontic components of dental implants were associated with the prevalence of peri-implantitis.

Methods: We enrolled 185 patients with 348 implants who underwent at least 1-year follow-up after the delivery of the prosthesis from February 2010 to January 2021. Demographic data of the patients and implants and the follow-up period were recorded. The emergence angle, type of cervical crown contour, and contour angle were analyzed using annual bite-wing radiographs. Peri-implantitis in this study was diagnosed if the peri-implant bone loss was greater than 2 mm between the bite-wing radiographs taken at baseline and the latest. Chi-square test, two-sample t-test, and multivariate logistic regression were used to investigate the differences and odds ratios between the peri-implantitis and non-peri-implantitis groups.

Results: The incidence of peri-implantitis was 14.9% during a follow-up period of 1509 days after the delivery of the prosthesis for at least 1-year. Based on the prevalence of non-peri-implantitis and after adjusting for confounding factors, the risk factors identified were bone types for implants (native bone vs. alveolar ridge preservation: adjusted odds ratio = 2.43, P = 0.04). Sex, arch, and guided bone regeneration vs. alveolar ridge preservation have the potential for a statistical difference.

Conclusions: Compared with implants at alveolar ridge preservation sites, implants in the native bone were more prone to peri-implantitis. Further randomized controlled trials are required to determine these associations.

Purpose: This study aimed to evaluate the risk of bone loss around single short molar crown-supporting implants in an atrophic mandible.

Methods: Implants of different lengths (L = 4 or 6 mm) and diameters (Ø = 4.1 or 4.8 mm) were placed in the molar area of an atrophic mandible. Additional control mandible models were simulated for 4.1 mm diameter implants (L = 4, 6, 8, and 10 mm). A vertical masticatory load of 200 N was applied to three or six occlusal contact areas (3ca or 6ca) of the prosthetic crown. The bone strain energy density (SED) of 109.6 µJ/mm³ was assumed to be the pathological threshold for cortical bone. The peri-implant bone resorption risk index (PIBRri) was calculated by dividing the maximum SED of the crestal cortical bone by the SED pathological threshold.

Results: Increasing the implant length from 4 to 6 mm, implant diameter from 4.1 to 4.8 mm, and number of contact areas from 3 to 6 reduced the SED and PIBRri values by approximately 20%, 35%, and 40%, respectively, when comparing pairs of models that isolated a specific variable. All models with 6ca had a low bone resorption risk (PIBRri<0.8), while the Ø4.1 short implant with 3ca had a medium (0.8≤PIBRri≤1.0) or high (PIBRri>1.0) resorption risk.

Conclusions: Increasing the diameter or occlusal contact area of a 4 mm short implant in an atrophic mandible resulted in reduced bone resorption risks, similar to or lower than those observed in a regular mandible with standard-length implants.

Purpose: Occlusal overload can cause late implant loss. However, whether the magnitude of the occlusal force is a risk factor for late implant loss remains unclear. Thus, this clinical study aimed to determine the relationship between the gonial angle (GoA), which is associated with the magnitude of occlusal force, and late implant loss.

Methods: All implants with fixed prostheses placed at the Niigata University Hospital between April 2006 and August 2019 were included in this retrospective study. The implants with and without late loss were compared. Relevant variables, including smoking habits, diabetes mellitus status, remaining dentition, implant length and diameter, prosthesis design, retention systems, splinting, and GoA were assessed. Log-rank test and Cox proportional hazards regression analysis were used to estimate the adjusted hazard ratio (aHR) and to calculate the corresponding 95% confidence intervals (CI) for late implant loss.

Results: A total of 919 patients (349 men and 570 women) with 2512 implants were included in this study. Cox proportional hazards regression analysis revealed that a 10° decrease in the GoA (aHR, 1.588; 95% CI, 1.115-1.766; P = 0.010), smoking habits (aHR, 3.909; 95% CI, 2.131-7.168; P < 0.001), and male sex (aHR, 2.584; 95% CI, 1.376-4.850; P = 0.003) were significantly associated with late implant loss.

Conclusions: Within the limitations of this retrospective study of 2512 implants, smaller GoA, smoking habits, and male sex were risk factors for late implant loss.

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-implant 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.

Patients: An 18-year-old woman sought treatment for caries of the anterior teeth after completing orthodontic treatment. Direct composite resin restoration was chosen because the patient preferred a minimally invasive and cost-effective treatment whenever possible. Based on diagnostic wax-up, veneer-shaped indices for composite resin injection were designed to replicate and restore tooth defects rapidly and accurately. The overall esthetic result was excellent after a 1-year of follow-up.

Discussion: Direct freehand composite resin restorations are clinically challenging. The recently proposed 3D printing index for the composite resin injection technique is helpful for direct restoration but is challenging to remove. The veneer-shaped indices avoid the formation of an undercut in the direction of removing the index, making them easy to remove after finishing the restorations.

Conclusions: Using veneer-shaped indices for composite resin injection enables rapid esthetic rehabilitation of labial tooth defects caused by caries. This approach reduces chairside time and operational difficulty while allowing for easy index removal after completing the restorations.

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.