Retention Force Research Articles

Retention and interfacial failure mechanism of single diamond grains in resin-bonded grinding tools

Abrasive grains and the associated bonding agent are the two significant components in the manufacturing of fixed abrasive machining tools. The material properties and interfacial bonding behavior between the grains and the bonding matrix determine machining performance. In precision machining processes with diamond abrasives, the primary failure modes of fixed abrasive tools are grain dislodgement and premature loss, leading to abrupt change in machining load and ultimately causing inaccurate and inefficient machining performance. This study develops a comprehensive model for understanding abrasive grain retention and interfacial failure mechanisms in resin-bonded diamond tools. Finite element analysis of a single diamond grain embedded in a resin matrix was conducted to examine the influence of the grain shape, protruding height, and orientation angle on critical interfacial failure force. A series of single diamond scratching experiments validated the model, revealing that the maximum retention force reached 43.56 N for grains with a 0.9 mm protruding height and a 60° orientation angle. The results also show that, within a specific grain size range, grain shape—quantified by the sphere deviation coefficient proposed in this paper, has the greatest impact on retention and failure behavior. Protruding height plays a secondary role, while the contribution of orientation angle is minimal. These findings provide valuable insights for the design, manufacture, and optimization of precision abrasive machining tools, particularly for applications requiring high precision and reliability.

Evaluation of tensile bond strength of two different cements used for luting zirconia coping to one-piece zirconia implant - An in vitro study

Aim: The purpose of this in vitro study was the evaluation of the tensile bond strength of two different cements used for luting zirconia coping to one-piece zirconia implant. Settings and Design: The study was designed in an in vitro study setting. Materials and Methods: A one-piece zirconia implant was scanned on laboratory scanner, and thirty zirconia implants were milled by computer aided manufacturing (CAM). Subsequently, the abutment surface of each zirconia implants were scanned in laboratory scanner and coping with a hole was designed by computer-aided designing software, which was used for milling by computer-aided manufacturing (CAM). After various surface treatments of abutment and intaglio surface of coping, fifteen sets were cemented by glass ionomer cement (Group I) and the other fifteen sets by adhesive resin cement (Group II). All thirty samples after thermocycling were dried and pulled out in a universal testing machine, and tensile retention force is noted in pounds per square inch (psi). Statistical Analysis Used: Values for tensile retention force were tabulated for both the groups. Mean and standard deviation are calculated. Independent t-value and P value were calculated. Results: The least tensile retention force was reported in Group I (165.86 ± 25.74 psi). Maximum tensile retention force was received for Group II (396.81 ± 78.32 psi). Independent t-test was applied from which t-value calculated was 10.85 and P value obtained was 0.001, which means that there exists a very high difference in tensile bond strength of cement in Group I and Group II. Conclusions: Better tensile retention forces were observed in samples cemented with adhesive resin cement when compared to samples cemented with glass ionomer cement.

Accidental ingestion of a fractured piece of orthodontic aligner: a case report

BackgroundIngestion and aspiration of orthodontic devices are rare occurrences, typically associated with components such as expansion keys, archwire segments, dislodged fixed appliances (including brackets, buccal tubes, and bands), as well as fractured metal or plastic appliances. This article describes the clinical diagnosis and treatment process of a case of accidental ingestion of a fractured piece of orthodontic aligner.Case presentationA 31-year-old female under orthodontic treatment by aligners accidentally ingested a fractured piece of the aligner. The special difficulty of this case is that the transparent orthodontic aligner has a low radiopacity. At the beginning, no foreign body was found in the commonly used soft tissue window, causing difficulty in its location until greyscale was adjusted to lung window. The 2-centimeter fractured piece was taken out under anesthesia and endoscopic surgery.ConclusionMaterials with low radiopacity should be read with a lower grayscale range. Fractured orthodontic appliances with low retention force should not continue to be worn until consultation with attending doctor.

Influence of Different Undercut Depths of Clasp Fabricated by Selective Laser Melting on Retentive Force.

The purpose of this study was to investigate the influence of undercut depths on abutment teeth regarding the retentive force of clasps fabricated through selective laser melting (SLM), and to compare them with conventional cast clasps. Akers clasps made of cobalt chromium alloy were fabricated using the SLM method (SLM), and the retentive forces were compared with clasps made with the conventional cast method (Cast). Three undercut amounts (0.25 mm, 0.15 mm, and 0 mm) were applied on the abutment tooth. The specimens were subjected to 10,000 repetitive insertion/removal cycles. SLM-0.15 showed slightly lower initial retentive force than the Cast specimens, it remained within an acceptable range. During insertion/removal test, the SLM-0.15 specimen showed a significant difference between the initial retentive force and the retentive force after 5,000 cycles, indicating that SLM-0.15 was the least likely to change in retentive force within the parameters established in this study. The inner clasp surface on the SLM groups had higher surface roughness before testing compared to the Cast specimen. Akers clasps fabricated by SLM demonstrated optimal initial retentive forces with smaller undercuts than conventional Cast clasps, and the retentive forces changed less with repetitive insertion/removal.

Cumulative effect of digital manufacturing techniques, preparation taper and finish line designs on the retention of aged temporary molar crowns − An in vitro study

ObjectiveThis study evaluated the effects of finish-line design, tooth preparation taper or total occlusal convergence (TOC), and digital production technology on the retention of provisional crowns for molars. Material and MethodsDifferent taper angles (10° TOC and 20° TOC) and finish line designs (chamfer and shoulder) were used to prepare four mandibular first molar teeth. Two subgroups of the prepared teeth received temporary crowns that were either “Computer-Aided Design” and “Computer-Aided Manufacturing (CAD/CAM) milled or 3D printed. Hence, eight test groups of temporary crowns containing 10 samples each were created. Groups 1–4 were milled, and Groups 5–8 were 3D printed specimens. A consistent procedure was used to cement 80 temporary crowns. The specimens were thermocycled for a total of 5000 heat cycles, initially at 5 °C for 30 s (dwell time) and then at 55 °C for 30 s. The pull-off force necessary to remove the temporary crowns was recorded, and the tensile strength, which served as the dependent variable, was calculated. Analysis of variance (ANOVA) was used to assess the variations in retention forces among the test groups. ResultsThe mean tensile strengths at maximum load [MPa] were higher in Groups 5, 6, 7, 8 (6.6 MPa, 6.91 MPa, 7.65 MPa, and 7.45 MPa respectively) as compared to the mean tensile strengths at maximum load [MPa] in Groups 1, 2, 3, 4 (2.35 MPa, 3.52 MPa, 3.21 MPa, and 2.45 MPa respectively). ConclusionFor extended periods, 3D-printed crowns with steeper preparation tapers (20° TOC) and shoulder finish lines exhibited enhanced retention.

Pull-Off Forces on Implant-Supported Single Restorations by Sticky Food: An InVitro Study.

To investigate the pull-off forces on implant-supported restorations caused by sticky food, to understand how much retention force cemented restorations must have to withstand chewing forces without unintentional retention loss. The influence of food type, restoration design, and surface treatment were investigated. Monolithic implant-supported CAD/CAM zirconia crowns were fabricated and divided into groups according to their design: no (NC), flat (FC) and high cusps (HC) and subdivided according to surface roughness: rough (r) and smooth (s) (n = 10/group). NC represented the control group. The crowns were fixed in a universal testing machine opposite to each other. Four sticky foods (caramel, fruit jelly, candy strips and licorice) and a resin crown remover were tested. These were heated (36.4°C), placed between the crowns and compressed, then tensile strength tests were performed. The maximum pull-off force was recorded (Newton [N]). Statistical analysis was performed using 3-way ANOVA. The highest mean pull-off force among food samples was with caramel_HC_r (12.09 ± 1.26 N), whereas the lowest was with licorice_FC_s (3.21 ± 0.15 N). For the resin crown remover, a mean pull-off force of 55.41 ± 3.87 N was measured in the HC_r group. Both food type and crown design showed a significant influence on pull-off force (p < 0.001), whereas no significant effect was reported with different surface roughnesses (p = 0.344). This study reported pull-off forces of up to 20 N between all-ceramic restorations caused by sticky food. The clinical implication of these findings is that a cemented implant-restoration must have a minimum retention force of 20 N to withstand unintentional displacement during function.

Drop Retention and Departure in Adiabatic Shear Flow on Structured Superhydrophobic Surfaces.

Drops are retained or held on surfaces due to a retention force exerted on the drop by the surface. This retention force is a function of the surface tension of the liquid, drop geometry, and the contact angle between the drop and the surface. When external or body forces exceed the retention force, the drop begins to move. This work explores the conditions for which drop departure occurs on structured superhydrophobic surfaces in the presence of an applied shear flow. Drop departure is explored for five microstructured superhydrophobic surfaces, one nanostructured carbon nanotube surface and one smooth hydrophobic surface. Surface solid fractions range from 0.05 to 1.00, and measured static contact angles range from 121° to 161°. Droplet volumes of 5, 10, 20, 30, 40, and 50 μL are tested on each surface. For each experiment, increasing air velocity is applied to a droplet placed on a surface until the droplet departs. High-speed imaging is used to track droplet base length, height, cross-section area (as viewed from the side) and advancing/receding contact angles. Measurements of drop advancing and receding contact angles are reported at the point of departure, with increasing contact angle hysteresis observed prior to departure. Contact angle hysteresis is observed to be a good indicator of droplet mobility. Measurements of the average air velocity over the height of the droplet are determined at the point of departure for all conditions. The measured air velocity shows strong dependence on the surface solid fraction, and the required shear flow velocity decreases as the surface solid fraction decreases. This is most pronounced at very low solid fractions. A coefficient of drag for the departing drops in shear flow is calculated and is shown to decrease with increasing Reynolds number.

A NOVEL MAGNETIC SYSTEM TO TREAT TOTAL HIP ARTHROPLASTY INSTABILITY

Dislocation after total hip replacement (THR) is a devastating complication. Risk factors include patient and surgical factors. Mitigation of this complication has proven partially effective. This study investigated a new innovating technique to decrease this problem using rare earth magnets.Computer simulations with design and magnetic finite element analysis software were used to analyze and quantitate the forces around hip implants with embedded magnets into the components during hip range of motion. N52 Neodymium-Iron-Boron rare earth magnets were sized to fit within the existing acetabular shells and the taper of a hip system. Additionally, magnets placed within the existing screw holes were studied. A 50mm titanium acetabular shell and a 36mm ceramic liner utilizing a taper sleeve adapter were modeled which allowed for the use of a 12mm × 5mm magnet placed in the center hole, an 18mm × 15mm magnet within the femoral head, and 10mm × 5mm magnets in the screw holes.Biomechanical testing was also performed using in-vitro bone and implant models to determine retention forces through a range of hip motion.The novel system incorporating magnets generated retentive forces between the acetabular cup and femoral head of between 10 to 20 N through a range of hip motion. Retentive forces were stronger at the extreme position hip range of motion when additional magnets were placed in the acetabular screw holes. Greater retentive forces can be obtained with specially designed femoral head bores and acetabular shells specifically designed to incorporate larger magnets. Mechanical testing validated the loads obtained and demonstrated the feasibility of the magnet system to provide joint stability and prevent dislocations.Rare earth magnets provide exceptional attractive strength and can be used to impart stability and prevent dislocation in THR without the complications and limitations of conventional methods.

Contact angle hysteresis on nonwetting microstructured surfaces: Effect of randomly distributed pillars or holes.

We present a numerical study of the advancing and receding apparent contact angles for a liquid meniscus in contact with an ultrahydrophobic surface with randomly distributed microsized pillars or holes in the Cassie's wetting regime. We study the Wilhelmy plate system in the framework of the full capillary model to obtain these angles using the heterogeneous surface approximation model for a broad interval of values of pillar or hole concentration and for both square and circular shapes of the pillars or holes cross-section. Three types of random placing of defects on the plate are investigated, i.e., two with restrictions: (1) with maximum and (2) with minimum distance between the defects (in these cases the defects are isolated), and (3) without restrictions (the defects can overlap). The results show that the type of defect distribution and also the type of the defects shape (circular or square) does not affect the magnitude of the two angles. The results of the numerical simulations showed that the retention force for a plate with randomly located defects is not greater, and for larger concentrations of pillars or holes, it is smaller than that for periodically spaced ones. Comparisons with experimental results for the receding contact angle on surfaces with pillars and with the advancing contact angle on surfaces with periodically arranged holes is carried out.

Retention or repulsion forces induced by bubbles trapped at the base of an immersed microparticle on a substrate

Retention or repulsion forces induced by bubbles trapped at the base of an immersed microparticle on a substrate

Application of digital impression and model in removable partial dentures for Kennedy classⅠandⅡdentition defects.

This study aimed to evaluate the application of digital impression and resin model technology in removable partial dentures (RPD) for Kennedy classⅠandⅡdentition defects. Patients with Kennedy classⅠorⅡdental defect were selected and grouped in accordance with the following denture production processes: digital impression/resin model/cast cobalt-chromium alloy framework group (group A), digital impression/resin model/laser printed titanium framework group (group B), alginate impression/plaster model/cast cobalt-chromium alloy framework group (group C), and alginate impression/plaster model/laser printed titanium framework group (group D), with 40 cases in each group. The final RPD was examined in place in the mouth, and the evaluation indicators included the retention force of clamp ring, the tightness of connector and base, and the accuracy of occlusion. The evaluation scores of each index were used for analysis on the Kruskal-Wallis rank-sum test. No statistically significant difference in the score of each index was found among the four groups in RPD. The cast cobalt-chromium alloy and laser-printed titanium framework RPD using digital impression and resin model can meet the clinical restoration requirements of patients with Kennedy classⅠandⅡdentition defects.

Droplet dynamics under shear flow on surfaces with different wettability

Droplet dynamics on surfaces under shear flow, which affects the efficiency of water condensate removal in condensation, are significant for investigation. The influencing factors include air velocity, droplet volume and surface wettability. Three smooth surfaces (HI, HO-POTS, and HO-PDMS) and three semi-textured surfaces (HI+SHO, HO-POTS+SHO, and HO-PDMS+SHO) are fabricated. Experiments are performed for droplets with different volumes under different air velocities. A centrifugal fan is used to generate channel flow, and a high-speed camera is utilized to capture droplet behaviors. The results show that motion of droplets with small deformation on smooth surfaces can be divided into two stages (Acceleration and Constant Speed). Critical velocity for the onset of droplet motion, as well as the velocity that droplet can reach at Constant Speed Stage, is affected by air velocity, droplet volume and surface wettability. The mathematical expression of retention force is derived, and forces are calculated to verify the force balances at Constant Speed Stage. Droplet behaviors on semi-textured surfaces are much different from those on smooth surfaces, especially when crossing the boundaries between smooth and textured areas. The HO+SHO surfaces display a better performance of droplet removal compared with the HI+SHO surface.

Retention and wear assessment of two different bar materials used in implant-retained mandibular overdenture

Abstract Aim To assess retention and wear of two different bar materials (cobalt chromium and poly ether-ether ketone) used in implant-retained mandibular overdenture subjected to chewing simulation Robota during 1 year of functional simulation. Patients and methods This study is a comparative laboratory study which was carried out on 14 models of implant-retained mandibular overdenture, for each model two implants were inserted. The 14 models were divided equally into two equal groups: group A (overdenture constructed over two implant analogs with bar attachment and clip made from cobalt chromium material), and group B (overdenture constructed over two implant analogs with bar attachment and clip made from poly ether-ether ketone material). Drilling of the models was done using milling machine and each model received two implant analogs inserted 11 mm from midline at canine region. The overdentures were constructed in the usual manners and the teeth were set in lingualized occlusion. The mandibular overdentures were subjected to 150 000 chewing cycles using Robota chewing simulator and 1080 insertion-removal cycles. Retention of the samples was measured by the universal testing machine and wear observed under USB digital microscope both of which were done at the beginning of the study and after 3, 6, 9, and 12 months. Results The retention force for group A decreased significantly from baseline 43.43 ± 5.25 to 35.56 ± 8.30 after 3 months of cyclic loading, with similar reductions after 6, 9, and 12 months. Group B also showed reductions from baseline 26.75 ± 2.32 to 21.29 ± 6.74 after 3 months, and similar patterns over time. Group A had no statistically significant wear changes after cyclic loading, with a baseline mean of 0.2904 ± 0.0008, changing to 0.2913 ± 0.0008 after 3 months, while group B showed similar nonsignificant changes. There were no statistically significant differences in wear between both groups at any time point. Conclusion Retentive forces decrease with increasing cyclic loading. However, both materials displayed acceptable retentive values. Wear values were nonsignificant between two studied groups.

Retention force of two different pickup strategies for Locator retained mandibular implant overdenture; an in-vitro study.

Retention force of two different pickup strategies for Locator retained mandibular implant overdenture; an in-vitro study.

The influence of uneven placement of mini dental implants on retention form of lower complete over denture: An in vitro study

Objectives: This in vitro study aimed to evaluate the effect of placing two mini-dental implant (MDI) at different heights on the retention form of the lower over denture (OD). Materials and Methods: Sixteen acrylic mandibular blocks and their corresponding ODs were prepared and divided into four groups (four sets per group) to represent an atrophic mandibular ridge with two MDIs placed parallel to each other at inter-implant heights (IHs) of 0.0, 1.5, 3.0, and 4.5 mm. The OD blocks were mounted on a manual pulling stand and pulled vertically 12 times to measure the peak tension load (N). The data were analyzed using one-way analysis of variance (ANOVA), and the differences between the means were compared (P &lt; 0.05). Results: One-way ANOVA showed a statistically significant effect of IH on the retention force of the OD blocks (P &lt; 0.05). The mean retention force (N) for evenly placed MDIs was as follows: 32.2 ± 0.95, 1.5 mm IH: 30.1 ± 0.56, 3.0 mm IH: 26.1 ± 0.71, and 4.5 mm IH: 27.4 ± 0.90. Conclusion: The retention force of the OD blocks was significantly affected by the vertical inter-implant distance. A significant reduction in the mean retention force was observed for ODs retained by MDIs placed at an IH &gt;1.5 mm.

Assessment of Retention of Implant Bearing Mandibular Overdentures with Various Attachments: A Three-Year Follow-Up.

Mandibular dentures are considered dubious in terms of retention in resorbed ridges. Implant bearing overdentures can be a solution to the abovesaid issue. Various attachments in use offer variations in retention and maintenance. The aim was to assess long term durability and retention of implant supported overdenture attachments. Two implant bearing overdentures were placed in 20 patients. Magnet and ball attachment were used and dentures were evaluated over a period of three years at different time intervals. Difference of attachments' performance between intervals was assessed with ANOVA test and Tukey HSD post hoc test and the level of significance was set at p<0.05. There was a decline in retention throughout research period in both categories; the ball and socket batch showed statistically significant (P<0.05) better retention force compared to that of magnet group. There was lesser decline in mean retention force of 10.97N±0.82 to 7.24N±0.903 from one month to three years in magnet attachment retained overdentures. Ball attachments offer better retentive forces than magnet category. Magnet bearing overdentures offer more durability in terms of retention.

Evaluation of open-face maxillary complete denture for patients with prominent premaxilla: a crossover study.

The establishment of good facial esthetics is one of the main objectives of complete denture construction. Unfortunately, it may be the caused issue for patients having a prominent premaxilla due to excessive lip support by the labial flange of the maxillary denture. Open-face dentures (OFD) may suggest suitable prosthetic management for these patients. However, clinical evidence regarding the efficiency of OFD is scarce. A total of 38 completely edentulous participants having prominent premaxilla and skeletal class I Angle's classification were enrolled in this study. Each participant received a mandibular complete denture and 2 opposing maxillary dentures; conventional (CD) and open-face (OFD). On the day of denture insertion, the participants were divided into 2 groups; CD-OFD and OFD-CD where CD-OFD group was instructed to use the mandibular denture and the maxillary CD for 3 months and then to use the maxillary OFD for another 3 months after a wash-out period of 2 weeks. While group OFD-CD was instructed to use the mandibular denture and the maxillary OFD for 3 months then to use the maxillary CD for another 3 months after a wash-out period of 2 weeks. The dislodging force of the maxillary dentures was evaluated using the universal testing machine and the patient perception of retention, esthetics, and comfort was evaluated using the Visual Analogue Scale (VAS). Evaluation was carried out 1 day, 1 month, and 3 months after denture insertion. The Student t-test was used to compare the 2 maxillary dentures and the intervals for each denture were compared by using the ANOVA test with repeated measures followed by a Post Hoc test (adjusted Bonferroni) for pairwise comparison. The significance of the obtained results was judged at the 5% level (P value). The dislodging force and patient perception of retention did not show significant differences between the 2 dentures, while the perception of esthetics showed significant differences throughout the follow-up period. Perception of comfort showed an insignificant difference only at the 3-month interval. Open-face maxillary dentures can be a suitable alternative for patients with prominent premaxilla to achieve satisfactory retention, aesthetics, and comfort.

Effect of material composition and thickness of orthodontic aligners on the transmission and distribution of forces: an in vitro study.

To investigate the effects of material type and thickness on force generation and distribution by aligners. Sixty aligners were divided into six groups (n = 10): one group with a thickness of 0.89mm using Zendura Viva (Multi-layer), four groups with a thickness of 0.75mm using Zendura FLX (Multi-layer), CA Pro (Multi-layer), Zendura (Single-layer), and Duran (Single-layer) sheets, and one group with a thickness of 0.50mm using Duran sheets. Force measurements were conducted using Fuji® pressure-sensitive films. The lowest force values, both active and passive, were recorded for the multi-layered sheets: CA Pro (83.1N, 50.5N), Zendura FLX (88.9N, 60.7N), and Zendura Viva (92.5N, 68.5N). Conversely, the highest values were recorded for the single-layered sheets: Duran (131.9N, 71.8N) and Zendura (149.7N, 89.8N). The highest force was recorded at the middle third of the aligner, followed by the incisal third, and then the cervical third. The net force between the incisal and cervical thirds (FI-FC) showed insignificant difference across different materials. However, when comparing the incisal and middle thirds, the net force (FI-FM) was higher with single-layered materials. Both overall force and net force (FI-FM) were significantly higher with 0.75mm compared to those with a thickness of 0.50mm. Multi-layered aligner materials exert lower forces compared to their single-layered counterparts. Additionally, increased thickness in aligners results in enhanced retention and greater force generation. For effective bodily tooth movement, thicker and single-layered rigid materials are preferred. This research provides valuable insights into the biomechanics of orthodontic aligners, which could have significant clinical implications for orthodontists. Orthodontists might use this information to more effectively tailor aligner treatments, considering the specific tooth movement required for each individual patient. In light of these findings, an exchangeable protocol for aligner treatment is suggested, which however needs to be proven clinically. This protocol proposes alternating between multi-layered and single-layered materials within the same treatment phase. This strategy is suggested to optimize treatment outcomes, particularly when planning for a bodily tooth movement.

Deformation and retentive forces variations of the additively manufactured cobalt-chromium and titanium alloys dental clasps

This in vitro study aimed to evaluate the additive manufacturing (AM) of cobalt chromium Co-Cr and titanium Ti alloy clasps for clinical use. After scanning the Ni-Cr die of the first molar, Akers' clasps were designed using computer-aided design/ computer-aided manufacturing (CAD/CAM). The clasps were manufactured from Co-Cr-W dental alloy and Ti-6Al-4V alloy powder using AM machines. Then, they were divided into two groups. The initial retentive force of the clasps was measured using a universal testing machine. Cyclic loading of the clasps was carried out by a specially designed insertion-removal testing apparatus in wet condition up to 5000 cycles. Retentive force was measured at 1000, 2000, 3000, 4000, and 5000 cycles. Moreover, the intaglio surface of each clasp was scanned using the scanner; and superimposition between the pre- and post-cycling clasp files was performed to evaluate deformation after cyclic loading. The fitting surfaces of retentive clasp tips were examined with a scanning electron microscope (SEM). Finally, it has been found that the initial retentive force for the Co-Cr group was 10.81 ± 0.37 N, and for the Ti group was 5.41 ± 0.18 N. Additionally, during the testing periods, both Co-Cr and Ti clasps continued to lose retentive force within the cycles of placement and removal. This effect was more prominent in the Co-Cr than in the Ti clasps. The distances between pre- and post-cycling in the retentive arm were −0.290 ± 0.11 mm and −0.004 ± 0.01 mm in Co-Cr and Ti alloys, respectively, and in the reciprocal arm were −0.072 ± 0.04 mm and −0.032 ± 0.04 mm in Co-Cr and Ti alloys, respectively. The retentive force required to remove the Ti clasps was found to be significantly lower than those required to dislodge the Co-Cr clasps. Co-Cr and Ti clasps lost significant amounts of retentive force from the initial use to the 3.5-year periods of simulated clinical use.

Management of Mandibular Condylar Sagittal Fracture Accompanied by Lateral Condylar Crest Defect.

The sagittal fracture of the mandibular condyle can be fixed with absorbable long screws. Absorbable long screws are generally inserted from the lateral crest of the condyle and are as close as possible to the medial pole of the condyle to obtain sufficient retention force. However, in clinical practice, patients with locally comminuted condylar fractures and partial defects in the lateral crest are often encountered. We validated the use of absorbable plates and long screws to fix mandibular condylar fractures with lateral crest defects, and postoperative follow-up showed good results. The preoperative design indicated that if conventional long screws were used, more soft tissue need to be pulled downward to achieve the appropriate drilling angle. If an absorbable plate was used, the degree of downward pulling of soft tissue was smaller, which can better protect the parotid gland tissue and facial nerve. The surgery was performed according to the preoperative design, using an absorbable plate scheme. Postoperative CT confirmed a stable anatomical reduction of condyle. Four-month follow-up showed that the patient's facial shape, occlusion, and mouth opening were all good. Follow-up CT showed good fracture healing. It is feasible to use absorbable plates and long absorbable screws to fix mandibular condylar sagittal fracture accompanied by lateral condylar crest defect.