Long-term survival and maintenance efforts of splinted teeth in periodontitis patients

Influence of mobility on the long-term risk of tooth extraction/loss in periodontitis patients. A systematic review and meta-analysis

The aim of this systematic review (SR) was to assess whether tooth mobility (TM) increases the risk of tooth extraction/loss. The protocol was registered in PROSPERO database (CRD42023485425). The focused PECO questions were as follows: (1) "In patients with periodontitis, undergoing periodontal treatment, are teeth affected by mobility at higher risk of being extracted/lost compared to non-mobile teeth, with a minimum follow-up of 10 years?" and (2) "In these patients, does varying degrees of tooth mobility increase the risk of tooth extraction/loss, with a minimum follow-up of 10 years?". Results were reported according to PRISMA statement. Electronic and manual searches were conducted to identify longitudinal studies. The different assessments of tooth mobility were pooled into three groups: TM0: Undetectable tooth mobility, TM1: Horizontal/Mesio-distal mobility ≤1 mm, TM2: Horizontal/Mesio-distal mobility >1 mm or vertical tooth mobility. Tooth loss was the primary outcome. Various meta-analyses were conducted, including subgroup analyses considering different follow-up lengths and the timing of TM assessment, along with sensitivity analyses. A trial sequential analysis was also performed. Eleven studies were included (1883 patients). The mean follow-up range was 10-25 years. The weighted total of included teeth, based on the sample size, was 18 918, with a total of 1604 (8.47%) extracted/lost teeth. The overall rate of tooth extraction/loss increased with increasing mobility: TM0 was associated with a 5.85% rate (866/14822), TM1 with the 11.8% (384/3255), TM2 with the 40.3% (339/841). Mobile teeth (TM1/TM2) were at an increased risk for tooth extraction/loss, compared to TM0 (HR: 2.85; [95% CI 1.88-4.32]; p < .00001). TM1 had a higher risk than TM0 (HR: 1.96; [95% CI 1.09-3.53]; p < .00001). TM2 had a higher risk than TM1 (HR: 2.85; [95% CI 2.19-3.70]; p < .00001) and TM0 (HR: 7.12; [95% CI 3.27-15.51]; p < .00001). The results of the tests for subgroup differences were not significant. Sensitivity meta-analyses yielded consistent results with other meta-analyses. Within the limits of the quality of the studies included in the meta-analyses, mobile teeth were at higher risk of being extracted/lost in the long-term and higher degrees of TM significantly influenced clinicians' decision to extract a tooth. However, most teeth can be retained in the long-term and thus TM should not be considered a reason for extraction or a risk factor for tooth loss, regardless of the degree of TM.

Changes in periodontal parameters of splinted versus non-splinted posterior teeth during ten years of supportive periodontal therapy - A retrospective evaluation

OBJECTIVES

To compare periodontal parameters of splinted posterior teeth versus control teeth over ten years of supportive periodontal therapy (SPT) and to assess the survival rate of splints.

MATERIAL AND METHODS

Retrospective data of 372 SPT-patients was screened for splints (composite/fiberglass-reinforced composite) in the posterior (molars/premolars) which were inserted at least ten years before due to increased tooth mobility. For each splinted tooth (test), a corresponding control tooth had to be present at the first SPT-session after splint insertion (T1). Data was assessed at T1 and ten years later (T2). Possible influencing covariates for splint survival (mobility degree/Eichner class) were tested by Cox regression. The change in clinical attachment level (ΔCAL), probing pocket depth (ΔPPD) and the testing of possible influencing covariates was analyzed by using mixed linear regression.

RESULTS

Twenty-four patients (32 splints, 58 splinted teeth) were included. Ten test and two control teeth were lost. No differences were observed between ΔCAL and ΔPPD of test teeth compared to control teeth (ΔCAL -0.38 ± 1.90 vs. 0.20 ± 1.27 mm; ΔPPD -0.17 ± 1.18 vs. 0.10 ± 1.05 mm). Twenty-two splints fractured during the observation period (survival-rate: 31%). Mobility degree and Eichner class did not influence time until fracture.

CONCLUSIONS

Splinting of periodontally compromised and mobile posterior teeth does not have any disadvantage regarding the clinical periodontal situation when regular SPT is applied. However, splint fractures occur very often.

CLINICAL RELEVANCE

Splinting of posterior teeth is a treatment option in addition to active periodontal therapy when patients are disturbed by tooth mobility but splints have a high susceptibility to fracture.

Comparing the Long-Term Success Rates of Tooth Preservation and Dental Implants: A Critical Review

Implant therapy is considered a predictable, safe, and reliable rehabilitation method for edentulous patients in most clinical scenarios. Thus, there is a growing trend in the indications for implants, which seems attributable not only to their clinical success but also to arguments such as a more “simplified approach” based on convenience or the belief that dental implants are as good as natural teeth. Therefore, the objective of this critical literature review of observational studies was to discuss the evidence concerning the long-term survival rates and treatment outcomes, comparing endodontically or periodontally treated teeth with dental implants. Altogether, the evidence suggests that the decision between keeping a tooth or replacing it with an implant should carefully consider the condition of the tooth (e.g., amount of remaining tooth and degree of attachment loss and mobility), systemic disorders, and patient preference. Although observational studies revealed high success rates and long-term survival of dental implants, failures and complications are common. For this reason, attempts should be made to first save maintainable teeth over the long-term, instead of immediately replacing teeth with dental implants.

Survival of nonsurgically splinted mandibular anterior teeth during supportive maintenance care in periodontitis patients

Background/purpose

Splinting mobile teeth is a choice to improve the patient's oral comfort. The purpose of this study was to assess the survival and stability of mobile anterior mandibular teeth after splinting in patients with periodontitis undergoing supportive periodontal therapy (SPT).

Materials and methods

Patients with splinted mobile anterior mandibular teeth were assessed retrospectively. Periodontal statuses were recorded at baseline and follow-up visits. Tooth and splint survival as well as splint repairs were recorded. Multilevel Cox regression analyses were performed to evaluate patient- and tooth-related factors that might have influenced the survival rates of splints.

Results

Sixty-one patients, collectively having 161 splints, were followed for an average of 5.44 years. On average, probing depth (PD) of splinted teeth decreased from 4.31 mm to 2.93 mm and clinical attachment loss (CAL) decreased from 5.02 mm to 4.58 mm. Alveolar bone was stable in the follow-up period. None of the splinted teeth were extracted, The overall survival rate of the splints was 65.2%. Splints made of composite resin alone were associated with a higher risk of breakage when compared to splints composed of composite resin with mesh grid strips.

Conclusion

Splinting showed long-term survival and splinting combined with periodontal supportive treatment is a feasible option to maintain mobile mandibular anterior teeth.

Timing selection for loosened tooth fixation based on degree of alveolar bone resorption: a finite element analysis

Objective

This study aimed to evaluate timing of fixation to retard bone absorption using finite element analysis(FEA).

Methods

Volunteer CT images were used to construct four models of mandibles with varying degrees of alveolar bone resorption. By simulating occlusal force loading, biomechanical analysis was made on the periodontal membrane, tooth root and surrounding bone (both cancellous and cortical) of mandibular dentition.

Results

The von Mises stress value of the periodontal structures was positively related with the degree of alveolar bone resorption, and the von Mises stress at the interface between the periodontal membrane and tooth root was increased significantly in moderate to severe periodontitis models. The von Mises stress at the interface between the periodontal cortical bone and cancellous bone was increased significantly in the severe periodontitis model. And the von Mises stress value with oblique loading showed significantly higher than vertical loading.

Conclusion

Teeth with moderate to severe periodontitis, loosened tooth fixation can be used to retard bone absorption.

Effects of Periodontal Splints on Biomechanical Behaviors in Compromised Periodontal Tissues and Cement Layer: 3D Finite Element Analysis

Background: In this study, we evaluated the effect of periodontal splints made from different materials on the stress distributions in compromised periodontal tissues and cement layers, using a computer simulation of mastication. Methods: Twenty-five 3D models were created for a segment of mandibular teeth with different periodontal splints bilaterally extended to the canines. The models were divided into five groups according to the different materials and thicknesses (mm) of the splints: the non-splinted group, PEEK 0.7 group, PEEK 1.0 group, FRC group, and titanium group. Each group was subdivided based on five bone loss levels. Tooth 41 of each model was subjected to vertical and oblique (θ = 45°) static loads of 100 N, respectively, onto the incisal edge. The von Mises stresses and maximum principal stress were analyzed using Abaqus software. Results: Oblique loading resulted in higher stresses on periodontal tissues, cement layers, and splints than those caused by vertical loading. The lower the supporting bone level, the greater the stress difference between the splinted groups and the non-splinted group. In model 133,331, with severe bone loss, the maximum von Mises stress values on the alveolar bone in tooth 41 under oblique loading dramatically decreased from 406.4 MPa in the non-splinted group to 28.62 MPa in the PEEK group and to 9.59 MPa in the titanium group. The four splinted groups presented similar stress distributions in periodontal tissues. The lowest stress level on the splint was observed in the PEEK 0.7 group, and the highest stress level was transferred to the cement layer in this group. Stress concentrations were primarily exhibited at the connectors near the load-carrying area. Conclusions: The tested splinted groups were all effective in distributing the loads on periodontal tissues around splinted teeth with similar patterns. Using splinting materials with low elastic moduli reduced the stress concentration at the splint connectors, whereas the tensile stress concentration was increased in the cement layer. Thus, the use of adhesive cement with a higher elastic modulus is recommended when applying less rigid PEEK splints.

Treatment of stage IV periodontitis: The EFP S3 level clinical practice guideline

BACKGROUND

The recently published clinical practice guideline (CPG) for the treatment of periodontitis in stages I-III provided evidence-based recommendations for the treatment of periodontitis patients, defined according to the 2018 classification. Stage IV periodontitis shares the severity and complexity characteristics of stage III periodontitis, but includes the anatomical and functional sequelae of tooth and periodontal attachment loss (tooth flaring and drifting, bite collapse, etc.), which require additional interventions following completion of active periodontal therapy.

AIM

To develop an S3 Level CPG for the treatment of stage IV periodontitis, focusing on the implementation of inter-disciplinary treatment approaches required to treat/rehabilitate patients following associated sequelae and tooth loss.

MATERIALS AND METHODS

This S3 Level CPG was developed by the European Federation of Periodontology (EFP), following methodological guidance from the Association of Scientific Medical Societies in Germany and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) process. A rigorous and transparent process included synthesis of relevant research in 13 specifically commissioned systematic reviews, evaluation of the quality and strength of evidence, the formulation of specific recommendations and a structured consensus process with leading experts and a broad base of stakeholders.

RESULTS

The S3 Level CPG for the treatment of stage IV periodontitis culminated in recommendations for different interventions, including orthodontic tooth movement, tooth splinting, occlusal adjustment, tooth- or implant-supported fixed or removable dental prostheses and supportive periodontal care. Prior to treatment planning, it is critically important to undertake a definitive and comprehensive diagnosis and case evaluation, obtain relevant patient information, and engage in frequent re-evaluations during and after treatment. The periodontal component of therapy should follow the CPG for the treatment of periodontitis in stages I-III.

CONCLUSIONS

The present S3 Level CPG informs clinical practice, health systems, policymakers and, indirectly, the public on the available and most effective modalities to treat patients with stage IV periodontitis and to maintain a healthy dentition over lifetime, according to the available evidence at the time of publication.

Periodontal-orthodontic interdisciplinary management of a “periodontally hopeless” maxillary central incisor with severe mobility: A case report and review of literature

BACKGROUND

Treating periodontally hopeless teeth with advanced bone resorption and severe tooth mobility is a great challenge for both orthodontists and periodontists. Biofilm-induced periodontal inflammation and occlusal trauma-related inflammation may synergistically aggravate tooth mobility. This case report illustrates that even periodontally hopeless teeth can be saved and have long-term stability with comprehensive periodontal treatment to control periodontal inflammation and promote periodontal bone regeneration and intricate orthodontic mechanical control to correct cross bite and occlusal trauma.

CASE SUMMARY

A 27-year-old female patient whose chief complaint was severe tooth mobility and discomfort of the maxillary incisor was diagnosed with severe aggressive periodontitis by clinical and radiographic examinations. To reduce tooth mobility and establish stable occlusion, we combined orthodontic treatment with periodontal therapy to preserve the tooth. Orthodontic treatment was performed after basic periodontal therapy and periodontal surgery. The loosened upper right central incisor was successfully retained, and the periodontal tissue remained stable during follow-up.

CONCLUSION

Teeth with severe mobility and bone loss can be saved through interdisciplinary treatment when periodontal inflammation is strictly controlled.

Tooth Loss after Jaw Curettage Surgery: Associated Factors and Potential Benefit of Splint Application

Background

This retrospective study is aimed at (I) assessment of tooth loss and related parameters after jaw curettage of benign lesions and (II) assessment of the outcome of jaw curettage supported by splint insertion after at least six months of follow-up. Material and Methods. For (I), patients who had jaw curettage surgery in the Department of Oral and Maxillofacial Surgery, Sun Yat-sen Memorial Hospital, Sun Yat-sen University (Guangzhou, China) from July 2015 to June 2019 were included. For part (II), consecutive patients who came to the department from July to December 2019 that were additionally treated with dental splinting were involved in this study. Based on the patient records, age, gender, initial tooth mobility, follow-up outcome, and potential tooth loss (intra- or postoperatively) were recorded. Based on available radiographs, alveolar crest bone loss and root surface area supported by bone (RSA) were determined.

Results

(I) 128 patients with 305 teeth were included, of which 40 teeth were lost (success rate 86.9%), without statistical difference in gender, age, or tooth type (P > 0.05). Tooth mobility, RSA, and the presence of alveolar crest bone defects were associated to tooth loss (P < 0.001). (II) 17 patients with a medium follow-up period of 11 months (range 9 to 13 months) were enrolled. All lesion-involving teeth supported by splint treatment at risks of loss were preserved, showing an effective tooth retention rate in 17/17 cases (74/74 teeth, success rate: 100%).

Conclusions

Tooth mobility and bone loss (lesion-related and/or periodontal) are potential risk predictors for tooth loss in the first year after jaw curettage surgery. Dental splints could be recommendable for teeth involved by jaw benign lesions with little bone support.

Efficacy of tooth splinting and occlusal adjustment in patients with periodontitis exhibiting masticatory dysfunction: A systematic review

OBJECTIVE

To evaluate the efficacy of tooth splinting (TS) and occlusal adjustment (OA) compared to no TS or OA in patients with periodontitis exhibiting masticatory dysfunction.

MATERIAL

The primary outcome criterion was tooth loss (TL), and the secondary outcome parameters were change in probing pocket depth (PPD), change in clinical attachment level (CAL), tooth mobility (TM), and patient-reported outcome measures (PROMs). Literature search was performed on three electronic databases (from 01/1965 to 04/2021) and focused on clinical studies with at least 12 months follow-up.

RESULTS

From a total of 1515 publications, 51 articles were identified for full-text reading, of which 2 retrospective case series on TS with low risk of bias and 1 randomized and 2 prospective studies on OA with unclear risk of bias were included. For TS, synthesis of data showed that in 72 patients, 26 out of 311 teeth (weighted mean incidence of TL 8.4%) and 156 out of 1541 teeth with no TS (weighted mean incidence of TL 10.1%) were lost over 2 years following non-surgical periodontal therapy. The randomized controlled clinical trial (RCT) indicated CAL gain for teeth with OA compared to no OA. For the effect of OA on TL, PPD, and TM, heterogeneous data were retrieved from the included studies.

CONCLUSIONS

Within the limitations of this review and based on a low level of evidence, it is concluded that TS does not improve survival of mobile teeth in patients with advanced periodontitis. OA on teeth with mobility and/or premature contacts may lead to improved CAL, while the effect of OA on the remaining periodontal parameters remains unclear.

The impact of splinting timepoint of mobile mandibular incisors on the outcome of periodontal treatment-preliminary observations from a randomized clinical trial

Objectives

To compare the outcome of periodontal parameters in mobile mandibular incisors which were splinted before or after full-mouth disinfection (FMD).

Materials and methods

Thirty-four periodontitis patients with ≥ 1 mobile mandibular incisor (mobility degree II/III, clinical attachment loss (CAL) ≥ 5 mm, relative bone loss ≥ 50%) were randomly allocated to group A or B. Patients received periodontal treatment (PT) including splinting of teeth 33–43 before (A) or after FMD (B). Patient (age/sex/smoking status/systemic diseases/number of teeth) and tooth-related parameters (mean probing pocket depth (PPD)/CAL/oral hygiene indices; for the overall dentition and region 33–43) were assessed prior to PT and 12 months after FMD by a blinded examiner. Therapy-related information was added (group/antibiotic therapy/surgical intervention).

Results

Twenty-six patients (A: 12; B:14) were re-examined. Two patients of group B did not need splinting after FMD because of reduction in mobility after FMD. Regression analysis revealed a positive association of antibiotic therapy with CAL_overall, PPD_overall, and PPD_33-43 (p ≤ 0.01). There is a trend toward a higher reduction of periodontal parameters at teeth 33–43 in group A (PPD_33-43: − 0.91 vs. − 0.27 mm; CAL_33-43: − 1.02 vs. − 0.47 mm).

Conclusions

Teeth splinted before or after FMD show a significant improvement in periodontal parameters 12 months after FMD. Splinting after FMD offered the option to detect reduction in mobility.

Clinical relevance

Despite a higher, but not statistically significant, improvement in periodontal parameters on teeth splinted before FMD, the results do not indicate which timepoint of splinting is more beneficial. The decision for the therapeutic procedure should therefore be made individually.

The impact of splinting mobile mandibular incisors on Oral Health-Related Quality of Life-Preliminary observations from a randomized clinical trial

AIM

To compare the Oral Health-Related Quality of Life (OHRQoL) of patients with mobile mandibular incisors before and after full-mouth disinfection (FMD) with and without splinting.

MATERIAL AND METHODS

Thirty-four periodontitis patients with ≥1 mobile mandibular incisor (degree II/III) were randomly allocated to the test or control group. All patients received FMD and the test group additional splinting of teeth 33-43. OHRQoL was assessed before (BL) and 3 months after FMD (RE) using the Oral Health Impact Profile (OHIP)-14. Data were compared within and between the groups (Wilcoxon test/Mann-Whitney U test).

RESULTS

Twenty-eight patients (13 test group/15 control group) were re-evaluated. FMD led to a reduction of the mean probing pocket depth (PPD; in mm) (test group: BL-PPD 3.89 ± 1.03, RE-PPD 2.82 ± 0.53; control group: BL-PPD 3.58 ± 0.66, RE-PPD 2.77 ± 0.59; each p ≤ .001), the mean clinical attachment level (CAL; in mm) (test group: BL-CAL 5.22 ± 1.38, RE-CAL 4.79 ± 0.85; control group: BL-CAL 4.58 ± 1.10, RE-CAL 4.41 ± 0.96; each p ≤ .05), and the mean OHIP-14 summary scores (test group: BL-OHIP 21.7 ± 11.06, RE-OHIP 9.9 ± 8.96, p = .0046; control group: BL-OHIP 16.8 ± 8.27, RE-OHIP 11.7 ± 8.55; p = .0217). The reduction of the OHIP-G14 scores was considerably higher in the test group but statistically not significant (p = .080).

CONCLUSIONS

The results show a positive impact of non-surgical periodontal treatment on OHRQoL and a possible tendency for further improvement by splinting mobile mandibular incisors.

Splinting of the Anterior Maxillary Teeth Using Glass-Ceramic Materials: A Case Report

Objective:

The aim of this study was to present the technique of splinting anterior maxillary teeth using heat-pressed glass-ceramic material in a clinical case with long-term follow-up.

Clinical Considerations:

Various materials, including fiber-reinforced tapes, glass fibers, composite resin, and partial coverage metal frameworks, have been used as splinting materials with encouraging clinical results.

Conclusion:

As shown in the presented case, glass-ceramic heat-pressing materials can be used successfully for the splinting of anterior teeth.

Treatment of an Endo-Perio Lesion with Ozone Gas in a Patient with Aggressive Periodontitis: A Clinical Case Report and Literature Review

The pulp and periodontium have obvious relationships that have been described in many studies. Pulp infections may affect periodontal tissues and vice versa. Teeth with endo-perio lesions have a worse prognosis than isolated endodontic or periodontal lesions. Elimination of endodontic and periodontal infections is essential for successful treatment, so co-operation between endodontists and periodontists is necessary. In this clinical case, a 44-year-old male presented with primary periodontal disease with secondary endodontic involvement in his lower right canine because of aggressive periodontitis. There was 10 mm of clinical attachment loss and 8 mm periodontal pocket mesial from the tooth and bone radiolucency periapical and lateral from the root. Periodontal therapy was followed by endodontic treatment. Periodontal therapy included root scaling and planing, treatment of the periodontal pocket with ozone gas, systemic antibiotics, oral hygiene instructions, and chlorhexidine rinsing. Endodontic therapy included root canal instrumentation with rotary endodontic files, irrigation, root canal treatment with ozone gas, and obturation with lateral compaction. Radiographs at a 6-month follow-up appointment showed complete healing of the periapical lesion and alveolar bone lateral to the root. Using an interdisciplinary approach to treat endo-perio lesions provides favorable clinical outcomes. Ozone therapy is beneficial for the successful treatment of endo-perio lesions with narrow periodontal pockets in patients with aggressive periodontitis and poor prognosis.

A Glass Fiber-Reinforced Resin Composite Splint to Stabilize and Replace Teeth in a Periodontally Compromised Patient

Combined periodontal and prosthodontic treatment demands of patients require a structured coordination of pretreatments and an adequate choice of restorations. This is especially true if multiple teeth are missing and insufficient crown-root ratios are obvious. A 40-year-old patient with a severe periodontitis (Stage IV, Grade C) was treated with active, nonsurgical periodontal therapy. Afterwards, a supportive periodontal therapy was provided with a recall interval of three to four months. Due to a high tooth mobility of the anterior teeth in the upper jaw and a missing left canine, a combination of a resin composite (Signum composite, Kulzer, Hanau, Germany) and a unidirectional glass prepreg fiber (Tender Fiber Quattro, MICERIUM, Avegno, Italy) was utilized to fabricate a splint in a labside approach to stabilize the remaining teeth. Moreover, an artificial denture tooth was adhesively luted to the splint. A temporary polymer-based material (Vita CAD-Temp, VITA Zahnfabrik, Bad Säckingen, Germany) was selected to supply the posterior teeth of the patient with a 3-unit fixed dental prosthesis (FDP), and both restorations were adhesively cemented. 19 months after insertion, a fracture of the fiber-reinforced resin composite splint occurred that was intraorally repaired. In spite of the fracture of the splint, all materials were functionally and esthetically stable over the follow-up period of 22 months.

Natural Tooth Pontic Using Recent Adhesive Technologies: An Esthetic and Minimally Invasive Prosthetic Solution

An implant-supported crown represents an established and validated option for single-tooth replacement; however, a restorative solution should be selected according to a wide number of factors including patient's desire, expectations, specific clinical conditions, and financial possibilities. The aim of this case report is to describe a conservative rehabilitation strategy for the replacement of a periodontally compromised mandibular incisor: the extracted natural tooth was used as a pontic bonded to adjacent elements with polyethylene fiber and resin composite. This way, a chairside fabrication of a resin-bonded fiber-reinforced prosthesis is possible, using the patient's own tooth. After showing a satisfactory functional and esthetic result, advantages and pitfalls of this technique along with available data on the literature regarding the natural tooth pontic are addressed. Both patients and clinicians should be aware of minimally invasive, successful solutions for single-tooth replacement; whether indicated or necessary, the natural tooth pontic technique leaves open other treatment options for the future.

Comparative Evaluation of Flexural Strength and Flexural Modulus of Different Periodontal Splint Materials: An In Vitro Study

Splinting of the mobile teeth is a critical part of periodontal management to improve the prognosis and longevity of stable results of periodontally compromised teeth with increased mobility. Different types of splints are used in the dental field based on their mechanical and physical properties.The objective of the current in vitro study was to evaluate the flexure strength and flexural modulus of different types of splinting materials, such as: composite block, ligature wire, Ribbond®, InFibra®, and F-splint-Aid® bonded utilizing Flowable composites resin material. Seventy-five bar specimens were prepared with the dimensions of 25 × 4 × 2 mm, utilizing split metallic mold. Specimens were divided equally (n = 15) into five groups (one control group, four test groups). Different layers of splinting material were placed in between the layers of composite before curing. All the specimens were subjected to a three-point bending test by using a universal testing machine to calculate the flexural strength and flexural modulus. The entire data was subjected to statistical tests to evaluate the significance. Specimens from composite block groups showed the least mean value for flexural strength (89.15 ± 9.70 MPa) and flexural modulus (4.310 ± 0.912 GPa). Whereas, the highest mean value for flexural strength (168.04 ± 45.95 MPa) and flexural modulus (5.861 ± 0.501 GPa) were recorded by Ribbond® specimens. Inter group comparison of flexural strength showed statistically significant differences (P-value < 0.05), whereas comparison of flexural modulus showed non-significant difference among the groups (P-value > 0.05). Within the limitation of the present study, it was concluded that the Ribbond® exhibits maximum flexural strength and flexural modulus, whereas the composite blocks recorded the least values. Still, the decision making depends on the clinical scenario and the unique characteristic of each splint material.

Evaluating Modeling and Validation Strategies for Tooth Loss

Prediction models learn patterns from available data (training) and are then validated on new data (testing). Prediction modeling is increasingly common in dental research. We aimed to evaluate how different model development and validation steps affect the predictive performance of tooth loss prediction models of patients with periodontitis. Two independent cohorts (627 patients, 11,651 teeth) were followed over a mean ± SD 18.2 ± 5.6 y (Kiel cohort) and 6.6 ± 2.9 y (Greifswald cohort). Tooth loss and 10 patient- and tooth-level predictors were recorded. The impact of different model development and validation steps was evaluated: 1) model complexity (logistic regression, recursive partitioning, random forest, extreme gradient boosting), 2) sample size (full data set or 10%, 25%, or 75% of cases dropped at random), 3) prediction periods (maximum 10, 15, or 20 y or uncensored), and 4) validation schemes (internal or external by centers/time). Tooth loss was generally a rare event (880 teeth were lost). All models showed limited sensitivity but high specificity. Patients' age and tooth loss at baseline as well as probing pocket depths showed high variable importance. More complex models (random forest, extreme gradient boosting) had no consistent advantages over simpler ones (logistic regression, recursive partitioning). Internal validation (in sample) overestimated the predictive power (area under the curve up to 0.90), while external validation (out of sample) found lower areas under the curve (range 0.62 to 0.82). Reducing the sample size decreased the predictive power, particularly for more complex models. Censoring the prediction period had only limited impact. When the model was trained in one period and tested in another, model outcomes were similar to the base case, indicating temporal validation as a valid option. No model showed higher accuracy than the no-information rate. In conclusion, none of the developed models would be useful in a clinical setting, despite high accuracy. During modeling, rigorous development and external validation should be applied and reported accordingly.