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.

Digital workflow for periodontal splinting with a guided device.

OBJECTIVE: To detail a technique for bonding periodontal splint precisely in a digital workflow. CLINICAL CONSIDERATIONS: Periodontal splinting can be considered to stabilize the mobile teeth, especially for mandibular anterior teeth. Reliable bonding of periodontal splints is a prerequisite for successful clinical performance. However, when bonding the indirect splint to place or making direct splint intraorally, there is a significant risk of mobile teeth drifting away from the splint. To guide accurate insertion of periodontal splint with no risk of displacement of mobile teeth, a guide device fabricated by digital workflow is introduced in this article. CONCLUSIONS: Periodontal compromised teeth can be provisionally fixed during splinting, with the help of the guided device, and precise bonding of the splint is readily accomplished by using such digital workflow. This technique is not only applicable to the lingual splints, but also suitable for the labial ones. CLINICAL SIGNIFICANCE: The use of a guided device, after being digitally designed and fabricated, enables to stabilize the mobile teeth, in case of any displacement during splinting. It is straightforward, and beneficial to reduce the risk of complications, such as debonding of the splint, and secondary occlusal trauma.

Dental trauma splints for the mixed dentition - A finite element analysis of splint material, splint extension, missing teeth, and PDL representation.

BACKGROUND/AIMS: Dental traumatic injuries are common in children during the mixed dentition stage. These injuries usually require splinting for stabilization, which is complicated by the various stages of the permanent tooth development and primary tooth exfoliation. The aim of this study was to evaluate the effect on mobility of splint materials and extensions for an avulsed central incisor, stabilized with and without the adjacent incisor under intrusive and extrusive loading with different periodontal ligament (PDL) conditions. MATERIALS AND METHODS: Seventeen 3D model variations were created from a CBCT scan of a 7-year-old patient without erupted permanent upper lateral incisors. A 1000 N palatal load on the right central incisor simulated the avulsion injury and created an increased alveolus and bone deformation, resulting in an increased PDL thickness of 0.45 mm. Wire-resin composite splints with 0.9 mm cross-section (WCS) or 1.0 mm diameter nylon-resin composite splints (NCS) were created. The models simulated conditions with and without the adjacent upper central incisor. Two PDL conditions were investigated, simulating detached PDL or PDL with polyether impression material-like properties. Mobility was calculated under simulated biting loads in horizontal and vertical (intrusive and extrusive) directions. RESULTS: The NCS allowed greater tooth mobility of the avulsed incisor than the WCS, irrespective of splint extension, PDL condition, or load application. During horizontal loading, polyether-like properties for the PDL allowed around 0.2 mm mobility of the avulsed tooth with the WCS, similar to the intact tooth, whereas a simulated detached PDL allowed 25% more mobility with a WCS than with a NCS. CONCLUSIONS: Based on the FEA analysis, a 1.0 mm NCS may be suitable for splinting avulsion injuries during the mixed dentition stage compared to the considerably more rigid WCS. The NCS models provided flexibility for PDL healing while maintaining stability, even when missing adjacent teeth increased span widths. Extensions beyond directly adjacent teeth did not alter the mobility with the NCS but should still be considered an extra protection in case of bond failure or exfoliation.

A digital technique for splinting periodontally compromised mobile teeth in the mandibular anterior region.

A digital technique for fabricating a periodontal splint is presented. The lingual surface of periodontally compromised mandibular anterior teeth is captured and registered to form the emergence profile of the periodontal splint. An accurate periodontal splint is fabricated for mandibular anterior teeth with increased mobility after scaling and root planing.

Photoelastic stress analysis of different types of anterior teeth splints.

BACKGROUND/AIMS: Traumatic dental injuries are highly prevalent and are considered an important health problem. The aim of this study was to evaluate the in vitro stress distribution around simulated traumatized teeth subjected to different types of splints by photoelastic analysis. MATERIALS AND METHODS: For each group, five models of maxillary and mandibular arches were made in photoelastic resin using prefabricated teeth models, which were fixed and adjusted in a semi-adjustable articulator. All splints were bonded with composite resin on the labial surfaces of the maxillary central incisors, the lateral incisors and the canine teeth, simulating trauma to the 11. The groups were divided according to the type of splint: control-without splint; rigid-brackets and 0.021 × 0.025 inch stainless steel wire; semi-rigid-brackets and 0.016 × 0.016 inch cobalt-chromium wire; fiber-fiberglass ribbon; and flexible-nylon thread. The groups were submitted to an occlusal force in a special device attached to a universal test machine in balanced, protrusive, and lateral occlusions. Then, the incisal edge of the 11 was ground to simulate infra-occlusion, and the tests were performed again. Five points were analyzed around tooth 11 with a polariscope, and the data were submitted to ANOVA and Tukey tests at a 5% level of significance. RESULTS: When centric occlusion was analyzed by comparing normal occlusion to infra-occlusion, all groups showed high stress values in infra-occlusion with statistical differences-except for the control group. When lateral occlusion was analyzed, the nylon splint showed lower statistical differences compared with the control, fiberglass, and rigid splint groups, which did not differ between each other. The semi-rigid splint did not differ from any group. CONCLUSIONS: Fiberglass and semi-rigid splints showed better stress distribution around the traumatized tooth under occlusal loads. The nylon splint showed characteristics of non-stress distribution.

Fractured alveolar process displacement evaluation-Effect of the rigidity of wire-composite splints.

BACKGROUNDS/AIMS: Traumatic dental injuries with bone fractures require rigid splinting. The degree of rigidity of the wire-composite splints can be challenging. The aim of this study was to evaluate the effect of the rigidity of different wire-composite splints on alveolar process displacement. MATERIAL AND METHODS: A model was created using polystyrene resin to simulate the anterior maxilla, bovine incisors to simulate maxillary incisors, and polyether impression material to simulate the periodontal ligament. An alveolar process fracture was created, while maintaining the labial bone connection with the PDL. Four wire-composite splints (0.3, 0.6, 0.9, and 1.2 mm in diameter) were compared with models without splints and with no fracture (n = 5). The alveolar process displacement was measured (3 times per model/per splint type) at the fractured and adjacent central incisor regions using a deflectometer (Instron) under functional cycling and static loading (100 N). Data (µm) were analyzed using RM ANOVA, followed by Tukey's HSD test (α = 0.05). RESULTS: The displacement at the region of the adjacent incisor was not influenced by the splint during static and cycling load (P > .05). The Tukey test demonstrated that the model without splints had significantly higher alveolar process displacement at the traumatized teeth than that of all other splint models (P < .001). Increasing the wire diameter from 0.3 mm to 0.9 mm significantly reduced the alveolar process displacement (P < .001). No difference was observed between the 0.9 mm (P = .123) and 1.2 mm (P = .219) wire-composite splints irrespective of the measured tooth regions. CONCLUSIONS: The rigidity of the wire-composite splint significantly influenced the mobility of the fractured alveolar process. The use of at least 0.9 mm wire was effective in reducing the fractured alveolar process displacement to a level that was similar to the adjacent teeth.

Clinical Effectiveness of 6.5-mm-Long Implants to Support Two-Implant Fixed Prostheses in Premolar-Molar Region: The Influence of Immediate Loading and the Length of Splinting Implant.

PURPOSE: The purpose of this retrospective clinical study was to assess the influence of immediate loading and lengths of splinted implants on the clinical effectiveness of 6.5-mm-long implants supporting two-implant fixed prostheses in the premolar-molar regions. MATERIALS AND METHODS: A clinical database was reviewed in a private dental center to select those patients who had 6.5-mm-long implants placed to support two-implant fixed partial prostheses in the premolar-molar regions of the maxilla and the mandible. All implants were immediately loaded. The study groups were defined according to the lengths of the implants. Two groups were identified: the short-short splinted group, when both implants had 6.5 mm lengths, and the short-long splinted group, when one implant was longer than 6.5 mm. A total of 48 dental implants were placed in 16 patients to support 24 two-implant fixed prostheses. The mean follow-up time was 14 ± 5 months. The short-short splinted group included 8 patients with 16 implants; the short-long splinted group included 16 patients with 32 implants. The main variable was implant survival, and secondary outcomes were marginal bone stability and prosthesis survival. RESULTS: The statistical analyses indicated an absence of significant differences between the two groups in terms of implant and prosthesis survival (100% for both groups and both variables); however, distal bone loss around the splinted implants was significantly higher in the short-long splinted group. Bone loss was 0.37 ± 0.55 mm in the short-short splinted group and 0.94 ± 0.66 mm in the short-long splinted group. CONCLUSIONS: Immediate loading of short (6.5-mm-long) implants in the premolar-molar regions did not jeopardize their survival. Two-implant supported prostheses had the same clinical effectiveness, whether extra-short implants were splinted to another extra-short implant or to a longer one.

Biological and Technical Complications of Splinted or Nonsplinted Dental Implants: A Decision Tree for Selection.

PURPOSE: To present an in-depth review on splinting versus nonsplinting the restorations of adjacent dental implants, in addition to discussing biological and technical complications associated with either choice; and to provide the clinician with a decision tree that serves in everyday judgments when it comes to addressing this issue. MATERIALS AND METHODS: A comprehensive literature review was performed for articles comparing success of splinted versus nonsplinted dental implants. RESULTS: There is no evidence to suggest that implementing either prosthetic design results in higher implant survival. Both designs tend to have their own set of complications, but there is compelling evidence to suggest that splinted restorations generally have less technical complications. CONCLUSION: Either splinting or nonsplinting are valid options for restoring adjacent implants, but each tend to face different biological and technical complications. Knowing which patients are more likely to face particular complications is strategic to provide patients with successful restorations.

Comparison of Stress and Strain Distribution Around Splinted and Nonsplinted 6-mm Short Implants in Posterior Mandible: A Finite Element Analysis Study.

PURPOSE: This study was designed to compare the biomechanical performance of splinted and nonsplinted short implants, in the posterior mandible, using finite element analysis. MATERIALS AND METHODS: Three-dimensional models of short implants with 2 different diameters (4 × 6 mm or 5 × 6 mm) were scanned, and CATIA (R21) was used to simulate the model of an edentulous lower jaw. Experimental groups were designed as follows: (1) D4L6-splinted (three 4 × 6-mm splinted implants), (2) D4L6-nonsplinted, (3) D5L6-splinted, and (4) D5L6-nonsplinted. A 100 N load was applied, and stress and strain values in surrounding bone were analyzed in specific nodes using ANSYS software (16.1). RESULTS: The maximum stress values under axial load were found in D5L6-splinted model, and under oblique load, D5L6-nonsplinted model had the maximum stress values. Under axial load, D4L6-splinted model showed maximum strain values, but when oblique load was applied, D4L6-nonsplinted model had the maximum strain values. CONCLUSION: Splinting adjacent short implants may provide less bone strain and stress, especially at the presence of lateral forces. Increasing the implant diameter may be effective in strain reduction, but does not seem to reduce the bone stress, regardless of the direction of the load applied.

Stress Distribution in Splinted and Unsplinted Implant-Supported Maxillary Overdentures: A 3D Finite Element Analysis.

INTRODUCTION: This study was accomplished to assess the biomechanical state of splinting in implant-supported maxillary overdentures. MATERIALS AND METHODS: Two models of maxillary overdentures were designed in SolidWorks 2011. The first model included 4 separate implants and ball abutments, whereas the second one included 4 splinted implants connected with a bar. Evaluation was performed in ANSYS Workbench software with 200 N load applied at the molar-premolar region, bilaterally. The maximum equivalent stress and strain (von Mises) was recorded and analyzed along a path between the implants in the crestal bone and the prosthetic attachments. RESULTS: First model presented higher values of strain in prosthetic attachment and higher values of von Mises stress in crestal bone. The second model presented higher stress concentration in the gingival tissue of premolar area (near the bar), whereas the peak stress values were reported within the most distal part of the soft tissue support of the prosthesis in the first model (unsplinted). CONCLUSION: Splinting maxillary overdentures implants is associated with significant lower stress levels in the surrounding bone tissue.

Long-term stability of splinted anterior mandibular teeth during supportive periodontal therapy.

OBJECTIVE: The aim of the study was to retrospectively assess the survival rate and stability of periodontally compromised and mobile anterior mandibular teeth after splinting in patients under supportive periodontal therapy (SPT). MATERIALS AND METHODS: Thirty-nine patients with splinted anterior mandibular teeth and SPT (≥1 visit/year) for 3-15 years were re-examined. Periodontal status, patient and tooth-related factors were assessed retrospectively before (baseline) and 3 years after splinting (n = 39 patients, 162 splinted teeth). For patients with splints inserted for more than 3 years, retrospective data after 5 (n = 30), 7 (n = 24), 10 (n = 16), 12 (n = 8) and 15 years (n = 4) was included, if available. At baseline, splinted teeth included at least one tooth with increased mobility combined with clinical attachment loss (CAL) ≥ 5 mm and ≥50% relative bone loss (RBL). Baseline RBL of splinted teeth was assessed for all patients. Change in RBL was assessed after 10 years, if available. RESULTS: No splinted tooth was lost within the first 3 years after splinting. One splinted tooth was lost 7 years after baseline and one 12 years after baseline. After 3 years mean(SD) periodontal probing depth of splinted teeth decreased from 3.39(1.41) mm to 2.12(0.37) mm and mean(SD) CAL from 5.61(1.66) mm to 5.09(1.67) mm and remained stable over the observation period. No change in RBL was observed over a 10-year period (p = .213). The survival rate of the splints until fracture or debonding was 74.4% after 3 years. CONCLUSIONS: Periodontally compromised splinted teeth show a high survival-rate and periodontal stability during SPT.

Impression technique for a complete-arch prosthesis with multiple implants using additive manufacturing technologies.

This article describes an impression technique for a complete-arch prosthesis supported by multiple implants where additive manufacturing technologies were used to fabricate a splinting framework and a custom tray. The technique presented uses a shim method to control the homogenous splinting acrylic resin and impression material during the procedure, thereby reducing laboratory and chairside time and the number of impression copings and laboratory analogs needed.

Crestal Bone Loss Around Adjacent Dental Implants Restored with Splinted and Nonsplinted Fixed Restorations: A Systematic Literature Review.

PURPOSE: The aim of this systematic review was to compare the crestal bone loss around splinted and nonsplinted adjacent implants. MATERIALS AND METHODS: To address the focused question, "Is crestal bone loss around adjacent implants different with splinted from that with nonsplinted restorations?," indexed databases were searched from 1965 up to and including May 2016 using various combinations of the following keywords: "implant," "splinted," "nonsplinted," "unsplinted," "connected," "unconnected," "nonconnected," and "bone loss." Letters to the editor, commentaries, historic reviews, case reports, case series, animal studies, and studies on full-arch rehabilitation were excluded. RESULTS: Six studies were included with titanium implants ranging from 114 to 1187 implants. All studies had nonsplinted and splinted restorations that ranged from 20 to 234 restorations and from 60 to 970 restorations, respectively. In all the studies, the follow-up period after the restoration placement ranged between 1 and 22 years, with a mean follow-up ranging between 3 and 10.18 ± 3.18 years. In all studies, the mean crestal bone loss for implants restored with nonsplinted restorations ranged between 0.30 ± 0.65 and 1.3 ± 0.2 mm, whereas the mean crestal bone loss for implants restored with splinted restorations ranged between 0.50 ± 0.8 and 1.22 ± 0.95 mm. CONCLUSION: Within the limitations of this review it is concluded that adjacent implants restored with splinted and nonsplinted fixed restorations did not exhibit a difference in crestal bone loss. The evidence from this systematic review suggests further investigation.

Influence of abutment tooth position and adhesive point dimension on the rigidity of a dental trauma wire-composite splint.

BACKGROUND/AIM: The influence of abutment tooth position and adhesive point dimension on rigidity of wire-composite splints, used in dental trauma, was evaluated in vitro. MATERIALS AND METHODS: A commercial artificial resin model was used. The central incisors served as injured teeth with increased mobility (degrees of loosening II tooth 21 and III tooth 11), whereas teeth 12/22 or teeth 13/23 served as non-injured teeth with physiological mobility. Horizontal and vertical tooth mobility before and after splinting was assessed, using a universal testing machine. Teeth were splinted with a wire-composite splint (0.8 mm). Four groups were assigned with respective abutment tooth position and adhesive point dimension: group 1 (13-11-21-23, 2 × 2 mm(2) ), group 2 (12-11-21-22, 2 × 2 mm(2) ), group 3 (12-11-21-22, 3 × 3 mm(2) ), group 4 (12-11-21-22, 4 × 4 mm(2) ). RESULTS: For each group, tooth mobility after splinting was significantly higher than the physiological tooth mobility (P < 0.05). For teeth 11 and 12, no significant differences between Group 1 and 2 (P > 0.05) were found in tooth mobility after splinting. Significant differences were found in horizontal tooth mobility after splinting of tooth 11 between Group 2 and 3, Group 2 and 4 and Group 3 and 4, respectively (P < 0.05), whereas significant difference was found in vertical dimension for tooth 11 only between Group 2 and 4 (P < 0.05). Significant differences were found in horizontal mobility of tooth 21 between Group 2 and 3, and Group 2 and 4 (P < 0.05). CONCLUSION: Splinting the injured teeth 11 and 21 and the bilateral uninjured abutment teeth (teeth 12/22 or teeth 13/23) with the stainless steel wire-composite splint (0.8 mm), can be considered flexible splinting. While mobility was still higher than in unaffected teeth, increase in size of the adhesive splinting point decreased horizontal but not vertical mobility in most cases.

Perception regarding factors related to periodontal therapy among general dental practitioners of Belgaum city - a questionnaire survey.

PURPOSE: To assess the perception regarding periodontists and periodontal therapy among general dental practitioners (GDPs) of Belgaum city. MATERIALS AND METHODS: A questionnaire study was conducted among 120 GDPs of Belgaum city comprising 13 closed-ended questions. The questions addressed the following variables: demographics of the dentist, service as GDP, periodontal services provided by the GDP and periodontal services referred to the periodontists. RESULTS: One hundred GDPs responded to the survey. 83% had specialists visit their practice and 78% felt the need for having a consultant periodontist attached to their practice. The procedures performed by the general dental practitioners were as follows: scaling (100%), scaling and root planing (78%), splinting (61%), gingivectomy (47%), ap surgery (24%), frenectomy (33%), crown lengthening (23%), root coverage procedures (12%), bone grafts (8%) and implants (8%). The procedures for which GDPs preferred the service of periodontists include bone grafts (87%), ap surgery (80%), root coverage procedures (77%), crown lengthening (63%) and others. 90% agreed that expertise is required for performing surgical periodontal procedures. 86% agreed that periodontists are competent to treat periodontal diseases. 38% to 55% noticed failures in periodontal procedures even after making use of a periodontist's service. 72% did not provide implant care in their clinic. 84% felt the role of periodontists was limited to post placement maintenance. CONCLUSION: A variety of periodontal services were offered by GDPs. The most common services were non-surgical in nature.

Treatment of horizontal root fractured central incisors and 30 months follow up: 2 case reports.

BACKGROUND: Horizontal root fractures are rare in comparison to other types of injuries and according to the literature account for between 0.2%?7% of all traumatic tooth injuries. CASE REPORTS: Case 1: A 12-year-old girl was referred to our clinic with a complaint of tenderness and mobility as a result of an orofacial injury in her permanent upper left central incisor. A horizontal fracture was diagnosed on the middle third of the root during radiographic examination. Case 2: A 12-year-old boy was referred to our clinic with an injury to his upper left central incisor. During radiographic examination a horizontal fracture was diagnosed on the middle third of the root. Semi-rigid splints were applied to the teeth for 4 weeks without further treatment in both of the cases and they were followed-up for 30 months. At the end of the 30th month, the teeth were vital and they had no clinical signs nor symptoms. Also the radiographic examination showed healing with hard tissue in the fracture line for both of the cases. CONCLUSION: Using semi- rigid splints without any further treatment resulted with hard tissue healing in both of the cases and was successful for the treatment of horizontal root fractures.

Influence of adhesive point dimension and splint type on splint rigidity--evaluation by the dynamic Periotest method.

AIM: To evaluate the influence of adhesive point dimension and splint type on the rigidity of wire-composite splints in vitro. MATERIALS AND METHODS: A custom-made artificial model was used. The two central incisors served as injured teeth (degrees of loosening III and II) and the two lateral incisors as non-injured teeth (physiological mobility). Horizontal and vertical tooth mobilities were investigated before and after splinting with the Periotest(®) method; the percent change was taken as the relative splint effect. Teeth were splinted with three types of wire-composite splints: Dentaflex (0.45 mm), Strengtheners (0.8 × 1.8 mm), and Dentaflex completely covered with composite. Four adhesive point dimensions (2, 3, 4, and 5 mm) were evaluated. Normal distribution was tested with the Kolmogorov-Smirnov test. Differences were evaluated with the anova and post hoc tests for pair-wise comparisons. Significance level was set at 0.05. RESULTS: The adhesive point dimension did not influence splint rigidity, in general ( P  = 0.288). Significant effects were found in non-injured teeth with the Dentaflex ( P  < 0.001) and in injured teeth with the Strengtheners ( P  < 0.001). The Strengtheners splint rigidity increased significantly with increasing adhesive point dimensions. The three splints showed significantly different effects at 5-mm adhesive point dimension ( P  < 0.001). CONCLUSION: Splint rigidity for injured teeth was influenced by adhesive point dimension only when splinting with Strengtheners. We recommend adapting splint rigidity by selecting different wires and reducing the adhesive point dimension to a minimum. Dentaflex can be used for flexible splinting, Strengtheners, and composite covered Dentaflex for rigid splinting.

Association between resting jaw muscle electromyographic activity and mandibular advancement splint outcome in patients with obstructive sleep apnea.

INTRODUCTION: The muscles of mastication are important in positioning the mandible and can therefore affect the patency of the upper airway. The aim of this study was to determine whether resting masticatory muscle activity influences the response to mandibular advancement splint treatment in patients with obstructive sleep apnea. METHODS: Thirty-eight adult patients with obstructive sleep apnea were recruited for the study. Baseline electromyographic activities of the right anterior and posterior temporalis, masseter, and submandibular muscles were recorded with surface electrodes while the patients were awake, in the upright and supine positions, with the jaw in the postural position, and with and without a mandibular advancement splint. Muscle activity of the patients with obstructive sleep apnea was compared between responders (apnea-hypopnea index change ≥50%, and <10 events per hour) and nonresponders (apnea-hypopnea index change <50%) to mandibular advancement splint treatment. RESULTS: There were 18 responders and 20 nonresponders to mandibular advancement splint treatment. The responders had a trend for increased muscle activity in all muscle groups and scenarios. The resting muscle activity of the submandibular and masseter muscles while lying at rest and of the submandibular and posterior temporalis muscles while lying with the mandibular advancement splint in place were significantly greater (P <0.05) in the responders than in the nonresponders. CONCLUSIONS: Inherent baseline differences in muscle activity between responders and nonresponders to mandibular advancement splint treatment in adults with obstructive sleep apnea were observed. This preliminary study suggests that there might be a correlation between responsiveness with mandibular advancement splint treatment and baseline muscle activity.

Impression techniques for multiple implants: a photoelastic analysis. Part I: comparison of three direct methods.

The purpose of this article was to compare through photoelastic analysis the stress distribution in 3 direct transfer techniques for implants with splinting. Three photoelastic resin blocks were made with 2 implants placed parallel to each other and 2 square transfer copings splinted. Both transfers were splinted with acrylic resin chemically activated in 3 different techniques: metallic sticks (T1), prefabricated acrylic bars (T2), or dental floss (T3). A circular polariscope was used, and the distortion energy (E) was calculated in 4 periods: 20 minutes and 3, 24, and 36 hours. Statistically significant differences were found among the 3 techniques (P < .05). The dental floss presented the greatest distortion energy values (T3 = 0.469 Kgf/mm(2)) and the metallic sticks the lowest values (T1 = 0.0 Kgf/mm(2)). Thus, the metallic sticks technique (T1) appears to be the most accurate protocol to be used for implant-supported prosthesis with multiple abutments.

Impression techniques for multiple implants: a photoelastic analysis. Part II: comparison of four acrylic resins.

Four commercial brands of chemically activated acrylic resin were compared through photoelastic analysis. Photoelastic resin blocks were made with 2 implants placed parallel to each other and 2 square transfer copings splinted. Both transfers were splinted with chemically activated acrylic resin: Dencrilay, Duralay I, Duralay II, and GC. Data were analyzed by 2-way analysis of variance and Tukey test (P < .05). Statistically significant differences were found among the 3 brands of chemically activated acrylic resin. Dencrilay showed greater dimensional alteration. Duralay I and GC are recommended for the transfer of the position of the multi-implants.