Mesial Side Research Articles

Randomized clinical trial of zirconia and polyetheretherketone implant abutments for single-tooth implant restorations: A 5-year evaluation

Statement of problemTitanium-supported polyetheretherketone (PEEK) abutments provide an economic alternative to zirconia abutments in esthetically important areas. Research comparing the performance regarding esthetics, longevity, and biologic parameters of PEEK abutments is lacking. PurposeThe purpose of this clinical study was to determine whether PEEK implant abutments provide similar esthetic and biologic parameters and survival rates as zirconia implant abutments. Material and methodsForty participants (age 20 to 50 years) receiving maxillary anterior and premolar implants were enrolled in the study and randomly assigned into 1 of 2 groups: Group PEEK (20 titanium-supported PEEK abutments) and group ZIR (20 zirconia abutments). Both groups were restored with pressed lithium disilicate ceramic crowns. Technical, biologic, and esthetic evaluation was performed at baseline and at 1, 3, and 5 years. The probing pocket depth, plaque control record, and bleeding on probing were recorded at the abutments (test) and compared with those at the corresponding contralateral teeth (control) and also between the 2 test groups. Standardized digital radiographs of the implants were made, and the bone level was recorded with the implant shoulder as the reference on the mesial and distal sides. The color difference between the peri-implant mucosa and control teeth gingiva and the discoloration of the implant crowns were determined with a spectrophotometer. The Student unpaired t test and repeated-measure ANOVA were used to statistically analyze the data (α=.05). ResultsFrom the 5-year evaluation, both PEEK and zirconia abutments with ceramic crowns showed 100% survival rate without any fracture or restoration loss. Differences in the biologic parameters of zirconia and PEEK abutments were statistically similar: mean probing pocket depth (group ZIR: 2.32 ±0.50 mm, group PEEK: 2.13 ±0.60 mm); mean plaque control record (group ZIR: 0.19 ±0.19, group PEEK: 0.15 ±0.17); and mean bleeding on probing (group ZIR: 0.12 ±0.11, group PEEK: 0.08 ±0.12). The mean marginal bone loss at 5 years was similar for implants supporting zirconia and PEEK abutments: mean mesial bone level (group ZIR: 1.8 ±0.5 mm; group PEEK: 1.9 ±0.6 mm), and mean distal bone level (group ZIR: 1.7 ±0.6 mm, group PEEK: 1.8 ±0.3 mm). The initial color difference (ΔE) between the peri-implant mucosa and gingiva of the analogous contralateral teeth diminished over time. No discoloration of the definitive restoration supported by PEEK or zirconia was detected over 5 years. ConclusionsAt the 5-year evaluation, zirconia and PEEK abutments exhibited the same survival rate with similar biologic and esthetic outcomes.

Assessment on the Precision of the Orthodontic Bracket Slot Dimensions Using Micro-computed Tomography (Micro-CT)

To evaluate the precision of the orthodontic bracket slot dimensions of 0.022 inch and to compare them with those of the manufacturers' specifications. The slots of upper-right central incisor brackets (n = 5) from 11 commercial bracket systems of three different manufacturers (3M Unitek: Victory Mini Metal, Clarity, SmartClip, Clarity SL; ORMCO/SYBRON: Mini Diamond Twin, Damon Q, Damon Clear; Dentsply/GAC: Ovation, Mystique, In-Ovation R, In-Ovation C) were measured. The orthodontic brackets were scanned using micro-computed tomography (micro-CT), and the bracket slots were measured using micro-CT images. The slot was measured at four different surfaces (occlusal, gingival, base, and face) for both mesial and distal sites. Data were subjected to ANOVA and unpaired t-tests. A p-value of ≤0.05 was considered statistically significant. All brackets had slot dimensions that were significantly larger (p < 0.05) than the stated 0.022 inch. 3M-victory were 11.99% larger (0.02509 inch) and the closest to the stated dimension and the ORM-Damon C were 24.07% larger (0.02948 inch) than the quoted slot size of 0.022 inch. Comparison between mesial and distal sides showed that 91% of the bracket slots were asymmetrical at their bases and 100% asymmetrical at their faces. All of the bracket system showed divergent walls from base to face with values ranging from 1.96 (3M-SmartClip) to 26.58% (ORM-Damon C). The actual measurements of 11 bracket systems from three different manufacturers were more substantial than the manufacturers' specifications, and the walls of the slots diverged from the bracket bases in all of the tested bracket system. Orthodontic bracket slots vary significantly from that of the manufacturers' specification. The orthodontist should anticipate such shortcomings and be able to modify treatment mechanics through additional wire bending in three spatial planes.

Morphological analysis of cementoenamel junction in premolars of Sri Lankans.

Cementoenamel junction is an anatomical landmark which indicates the meeting point of enamel of the crown and the cementum of the root. It is an important reference point in clinical dentistry as well as in dental radiography. The present study is done to describe the distribution of the mineralized tissue at the cementoenamel junction in relation to various surfaces of the premolars. The study sample consisted of 89 permanent maxillary and mandibular premolars from both males and females extracted for orthodontic reasons. They were stained with carbol fuchsin and observed under a dissecting microscope to identify the following tissue interrelationships at the cementoenamel junction: cementum overlapping the enamel; edge-to-edge relationship between enamel and cementum; gap between the enamel and cementum and enamel overlapping the cementum. The cementum overlapping the enamel interrelationship was predominant in the buccal and lingual surfaces of both first and second maxillary premolars, while the edge-to-edge relationship and the presence of a gap between the enamel and the cementum relationship were abundant in distal and mesial sides. Enamel overlapping the cementum was recorded only in a very small proportion of the sample. A good understanding about the morphological variations at the cementoenamel junction area is very important and this area should be handled carefully during routine dental procedures such as dental bleaching, orthodontic treatment, placement of rubber dam and placement of dental materials.

Evaluation of bone gain and implant survival after vertical and horizontal ridge augmentation using titanium mesh with simultaneous implant placement in deficient maxillary and mandibular ridge: A prospective clinical study

The present clinical study was conducted with a one-stage approach for alveolar ridge augmentation using titanium mesh with simultaneous implant placement in the compromised ridges. This prospective study included a total no. of 26 partially edentulous sites which were treated with implants and simultaneous guided bone regeneration with titanium mesh. We found a significant increase in the bucco-lingual width at implant site when comparison was made at different time intervals. We found a significant decrease in the mean bone density on the mesial side (1934.62 ± 598.26 gray units), while no significant decrease in the mean bone density was found on the distal side ( 1873 ± 576.12 gray units) when compared at immediate post-operative and 6-months post-operative time interval. Despite the use of micropore titanium mesh, we have noticed membrane exposure in 10 patients (71.42%) among 14 patients which resulted in detrimental influence on the amount of bone augmentation. The bucco-lingual width of the alveolar crest has been significantly increased, but we couldn’t achieve any optimal gain in alveolar crest height.

Functional Evaluation of a Novel Multi-Axial Alveolar Distractor—Preliminary In Vivo Animal Study

This study evaluates the biomechanical performance of a new multi-axial alveolar distractor using an animal study. The multi-axial alveolar distractor is designed with a ball and socket joint mechanism that can rotate up to 60° toward the buccal/lingual and mesial/distal sides intra-operatively to achieve vector control. The transport segment can be moved through activating the transport screw with 0.25 pitch, allowing 13 mm in distraction height. This distractor was fixed at the right angulus mandibular of experimental rabbits and adjusted 15° toward the mesial side and 25° toward the buccal side as Group TMB (toward mesial-buccal) (n = 3), and 15° toward the mesial side as Group TM (toward mesial) (n = 3). Group TC (control) was the control group. The distractors were activated 1 mm/day for 13 days. Living bone growth was observed at various periods. The total bone growth length at the angulus region and buccal side distraction thickness after distraction were calculated. The variations in bone growth geometric shape at the mandible angulus were also recorded. Fracture testing was performed to understand the variations in the mechanical strength between the distracted and intact bone specimens. The digital radiography results showed that the osteotomy areas at the mandible angulus were healed and the bone growth completed after surgery. The average bone growth length of Group TMB was 17.68 mm. This was greater than that of Group TM at 14.79 mm. The corresponding buccal side distractor thicknesses for Group TMB and TM after distraction were 5.12 ± 0.52 mm and 3.32 ± 0.37 mm, respectively. The tensile strengths of the bone specimens after distraction of Groups TMB, TM and TC were 172.13 N, 119.27 N and 304.24 N, respectively, and the percentage of distraction bone tensile strength to normal bone was 57% and 39% for Groups TMB and TM, respectively. This study concluded that this new multi-axial alveolar bone distractor can drive bones to grow in accordance with the direction/angle of the distraction plan. The bone growth healed gradually and presented insufficient mechanical strength.

Effect of Platelet-Rich Plasma on Bone Healing in Immediate Implants Analyzed by Cone Beam Computerized Tomography: A Randomized Controlled Trial.

The possibility of platelet-rich plasma (PRP) on the improvement of bone and adjacent tissue recovery has previously been validated. However, there is insufficient data supporting the use of platelet-rich plasma to improve the healing of bone and adjacent tissues around an implant in the oral cavity. The purpose of this randomized controlled trial was to observe the effect of platelet-rich plasma (PRP) concentrate on marginal bone loss and bone density around immediate implant placement using Cone Beam Computerized Tomography (CBCT). This clinical study was conducted over a period of six months on 12 subjects, who were equally categorized into two groups. Group I was the control, whereas the subjects in Group II received PRP therapy at the surgical site. All subjects were given a standard treatment with a single implant system (DIO UFII hybrid sandblasted acid-etched implants). Inserted implants were analyzed through CBCT, and records were registered at baseline, at the 12th week before functional loading and the 26th week after functional loading. The bone loss was calculated at the proximal (mesial and distal) side of the implant and bone density at baseline, 12th week, and 26th week after implant placement. SPSS version 23.0 was used for statistical analysis of data. The changes in bone levels were measured and compared between the two groups using the Mann–Whitney U test, with no significant difference. Bone density was analyzed by an independent sample t-test, p value ≤ 0.05 was considered statistically significant. Again, no significant difference in bone density was observed between both groups at all three instances. Therefore, it can be concluded that local injection of PRP after immediate implant placement did not show any decrease in marginal bone loss or improvement in bone density. This trial is registered with NCT04650763.

Comparison of laser and piezo incisions to accelerate orthodontic tooth movement - A pilot rat model study

Aim: The aim of this study was to determine changes in bone structure after laser and piezo incisions evaluated with micro-computed tomography (micro-CT).Materials and Methods: Forty-eight adult male Sprague Dawley rats were randomly divided into 4 groups: no additional intervention to accelerate tooth movement (n=15), laser incision (n=15), piezocision (n=15), and control (n=3). These groups were divided into subgroups based on duration of applied force: 0, 3, 7, 14, 21, and 28 days. Piezo and laser incisions were made vertically on the mesial palatal side of the left maxillary molar without flap elevation. Tooth movement, bone volume, and bone mineral density were evaluated with micro-CT. P values less than 0.05 were considered statistically significant.Results: There were no significant differences in bone mineral density, bone volume, or amount of tooth movement between time points in any of the groups. The amount of tooth movement was significantly different between the groups at day 21.Conclusion: These findings provide some initial basic understanding of changes in the bone following tooth movement alone and with piezocision and laser incisions. Larger sample sizes are needed to better elucidate their effects.

Internal Hexagon vs Conical Implant-Abutment Connections: Evaluation of 3-Year Postloading Outcomes.

Different types of internal implant-abutment connections, namely hexagon and conical, have been used for implant restoration. However, data regarding the benefits of these internal connections in terms of clinical outcomes are scarce. Accordingly, the aim of this study was to compare radiographic marginal bone loss (RMBL) and associated implant complications between implants with internal hexagon (IH) connections and those with internal conical (IC) connections. Forty-nine patients with 98 implants (2 per patient) placed in the posterior mandible were recruited. All implants were inserted in pairs into solid D2 bone according to a randomized sequence; the first patient received an IH connection implant on the mesial side, while the second patient received an IC connection implant on the mesial side. Each patient received 1 implant with an IH connection and 1 with an IC connection, placed side by side. Four months after placement, all implants were loaded with single screw-retained ceramic restorations with IH or IC connections. RMBL and complications, including implant/prosthesis failure, were recorded at the time of implant loading (baseline) and at 6, 12, and 36 months after loading. The results revealed no significant between-group differences in RMBL (P = .74), gingival bleeding on probing (P = .29), and complications (P = .32). Thus, the type of internal implant-abutment connection did not affect clinical outcomes, including RMBL and implant/prosthesis failure. Future studies should additionally evaluate long-term prosthesis-related complications, such as screw loosening and fracture, between the 2 types of internal connections.

Marginal bone stability around bone level versus tissue level implants in non-compliant patients with healthy or reduced periodontium: A 10-year retrospective study

The aim of this retrospective study was to investigate the effects of bone level implants (BL) in non-compliant patients on marginal bone alterations compared with the tissue level implants group (TL) at a mean follow-up period of at least 10 years.This study reports on 44 non-compliant patients selected from 3 private practices located in Beirut. Patients selected underwent implant surgery between 2005 and 2009 and had BL (Branemark and 3I Biomet) or TL (Straumann) implants. Periapical radiographs were taken directly after loading and at least at 10 years later. Crestal bone loss (CBL) for a total of 140 implants, including 97 BL and 43 TL implants was measured on radiographic images using the image tool software. Image calibration was done according to implant length. Hygiene level, smoking status and implant surface were also registered.After a mean period of 10 years, implants in the TL group had a mean CBL of 1.18± 0.89 (0.85 on the mesial side and 1.5 on the distal side). The BL group showed a mean CBL of 0.97 ± 0.64 (0.65 on the mesial side and 1.29 on the distal side). No significant difference (p &gt;0.05) was found between the 2 groups. Hygiene level was significantly associated with mesial and average bone loss. TiUnite surface showed a lower distal bone loss compared to SLA and acid etched surfaces. Furthermore, the average bone loss was significantly elevated in multiple-implant compared to single-tooth fixed implant restorations. No significant difference in bone loss was found between the maxilla and the mandible or between non-smokers and smokers.Analysis of the obtained results did not reveal a lower bone loss between bone level and tissue level implants in patients who didn’t commit to a strict maintenance program. However, bone loss was strongly correlated to hygiene level, confirming the importance of SPT and compliance.

Risk assessment of interproximal contact loss between implant-supported fixed prostheses and adjacent teeth: A retrospective radiographic study

Statement of problemStudies of interproximal contact loss (ICL) associated with implant-supported fixed prostheses (ISFPs) have typically used dental floss or metal strips to determine ICL and have shown a high prevalence of 34% to 66%, which does not match the authors’ experience. Moreover, the implant prosthetic factors contributing to ICL have seldom been reported. PurposeThe purpose of this clinical study was to examine follow-up radiographs of ISFPs to determine the prevalence of open contacts between the ISFP and adjacent teeth and to assess the risk factors associated with ICL at patient, implant prosthesis, and adjacent tooth levels. Material and methodsPatients treated with ISFPs at a single clinical center were included. Digital radiographs obtained at the time of ISFP delivery and subsequent follow-up were assessed, and a total of 180 ISFPs with 296 interproximal contacts in 147 patients were screened for analyses. The prevalence and risk factors of ICL at the levels of patient (age, sex, diabetes, smoking, and bruxism), implant prosthesis (follow-up period, arch location, splinting, ceramic or metal materials, screw or cement-retained, and abutment-fixture connection), and adjacent tooth (mesial or distal side, contact with unrestored tooth, composite resin restoration, or fixed prosthesis, vitality, bone height, and contralateral spacing) were analyzed with logistic regressions and generalized estimating equation (GEE) analyses (α=.05). ResultsThe onset of ICL was from 6 to 96 months after ISFP delivery. The prevalence of ICL at the patient level was 15.0%, at the implant prosthesis level 13.3%, and at the adjacent tooth levels 8.8%. Twenty-six of the participants had 2 or more ISFPs. The multivariable GEE analysis reported that sex at patient level; longer follow-up period and implant prostheses with external hexagonal and internal octagonal connections at implant prosthesis level; and contralateral spacing, contact with composite resin filling and mesial side of ISFP at adjacent tooth level were significant risk factors of ICL, where contralateral spacing had the highest adjusted odds ratio of 20.88 (P=.002). ConclusionsMost of the ICL were found at the mesial side of ISFPs, and the odds of ICL was significant in participants with longer follow-up periods. Internal hexagonal connections reported relatively lower risk than others. Factors relevant to the anterior component of occlusal force, such as male sex, contralateral spacing at adjacent tooth, and proximal contact of ISFP with resin filling, seem to be high risk factors for ICL.

Evaluation of temperature rise in the pulp during various IPR techniques\u2014an in vivo study

BackgroundNon-extraction treatment protocol has gained a lot of popularity over extraction for orthodontic treatment. Interproximal enamel reduction is one such method that makes it possible to do orthodontic treatment without extractions. This procedure, which can be done by various techniques, leads to a rise in the temperature of the pulp of the teeth. Previously, studies have been done which have evaluated the temperature changes inside the pulp chamber of extracted teeth, during interproximal enamel reduction. However, no documented literature exists that has evaluated these changes in the live pulp of the teeth whilst interproximal enamel reduction (IPR) is being performed. Therefore, this study aimed to evaluate the temperature changes inside the live pulp of the teeth during various interproximal enamel reduction techniques in vivo.AimsEvaluation of temperature rise in the pulp during various interproximal enamel reduction techniques, done in vivo.Material and methodThe study was performed on patients for whom extraction of premolars had been advised for their orthodontic treatment. Fifty-one premolar teeth were randomly divided into three groups of IPR, i.e. using airotor and bur, handheld metal strip and orthodontic IPR kit (oscillating system). IPR was performed on the mesial and distal sides after access opening, temperature change was recorded during IPR and the readings were compared. The Shapiro-Wilk test was utilized for checking whether the data satisfied the requirement of normal distribution.ResultsThe highest temperature rise was seen in group 1 in which interproximal enamel reduction was performed using airotor and bur. The minimum temperature rise was observed in group 2 in which interproximal enamel reduction was done using the handheld metal strip, whereas the temperature rise observed in group 3, in which interproximal enamel reduction was done using IPR kit, was between the range of group 1 and group 3. The temperature change was in the following order—group 1 (2.08 °C) > group 3 (1.22 °C) > group 2 (0.52 °C).ConclusionNone of the methods used to perform interproximal enamel reduction caused a temperature increase more than 5.5 °C, beyond which pulp necrosis may occur. Therefore, all three methods used in the study for IPR were found to be safe.

Open Proximal Contact with Implant-Supported Fixed Prostheses Compared with Tooth-Supported Fixed Prostheses: A Systematic Review and Meta-analysis.

To investigate the odds of developing open proximal contact (OPC) between implant-supported fixed prostheses and adjacent teeth compared with that between tooth-supported fixed prostheses and adjacent teeth. A search was conducted in the Ovid MEDLINE, Embase, and Web of Science databases for clinical studies on OPC developed with implant-supported prostheses or tooth-supported prostheses. A meta-analysis was performed using statistical software to estimate the odds of developing OPC with implant-supported prostheses compared with tooth-supported prostheses, with a 95% confidence interval (CI). The statistical significance was defined as P < .05. The odds ratio (OR) of developing OPC with implant-supported prostheses was 2.46 compared with tooth-supported prostheses (95% CI [1.21 to 5.01]; P = .013]. However, the data were highly heterogenous (τ2 = 0.40, I2 = 95.67%). The total estimates of developing OPC were 41% (95% CI [30% to 54%]) with implant-supported prostheses and 22% (95% CI [18% to 26%]) with tooth-supported prostheses. OPC was more prevalent at the mesial side than at the distal side of implant-supported prostheses (OR = 2.38, 95% CI [0.94 to 6]; P = .066), whereas OPC was more prevalent at the distal side than at the mesial side of tooth-supported prostheses (OR = 1.94, 95% CI [1.09 to 3.45]; P = .024). There was no statistically significant difference in developing OPC with covariates of sex, age, arch, splinting of implants or adjacent teeth, region, and vitality of adjacent teeth, retention type, opposing dentition, occlusal force, parafunctional activities, and follow-up time. OPC was found to increase 9% per year with implant-supported prostheses (OR = 1.09). The estimate of interproximal gap next to implant-supported prostheses was 245.8 μm (95% CI [86.4 to 405.3 μm]). Within the limitations of this systematic review and meta-analysis, the odds of developing OPC were significantly higher with implant-supported prostheses than with tooth-supported prostheses. However, the data were highly heterogenous, and thus, a well-designed randomized clinical study needs to be conducted to validate the results of this systematic review.

Integrating Finite Element Death Technique and Bone Remodeling Theory to Predict Screw Loosening Affected by Radiation Treatment after Mandibular Reconstruction Surgery.

This study developed a numerical simulation to understand bone mechanical behavior and micro-crack propagation around a fixation screw with severe mandibular defects. A mandible finite element (FE) model was constructed in a rabbit with a right unilateral body defect. The reconstruction implant was designed to be fixed using six screws distributed on the distal and mesial sides. The element death technique provided in FE analysis was combined with bone remodeling theory to simulate bone necrosis around the fixation screw in which the strain value reached the overload threshold. A total of 20 iterations were performed to observe the micro-crack propagation pattern for each screw according to the high strain locations occurring in each result from consecutive iterations. A parallel in vivo animal study was performed to validate the FE simulation by placing specific metal 3D printing reconstruction implants in rabbits to compare the differences in bone remodeling caused by radiation treatment after surgery. The results showed that strain values of the surrounding distal bone fixation screws were much larger than those at the mesial side. With the increase in the number of iteration analyses, the micro-crack prorogation trend for the distal fixation screws can be represented by the number and element death locations during the iteration analysis process. The corresponding micro-movement began to increase gradually and induced screw loosening after iteration calculation. The strained bone results showed that relatively high bone loss (damage) existed around the distal fixation screws under radiation treatment. This study concluded that the FE simulation developed in this study can provide a better predictive diagnosis method for understanding fixation screw loosening and advanced implant development before surgery.

Crestal Bone Changes and Patient Satisfaction with Single Implant-Retained Mandibular Overdentures with Dalla Bona and Locator Attachments with Immediate Loading Protocols. A Randomized Controlled Clinical Study.

There is no enough evidence present on the success of single implant-retained mandibular overdentures (SIMO) with Dalla Bona and Locator attachments. This study aims to compare crestal bone loss and patient satisfaction with SIMO with Dalla Bona and Locator attachment following immediate loading protocols. Twelve patients included in Group 1 received immediate SIMO with Dalla Bona attachments, and another twelve patients in Group 2 received immediate SIMO with Locator attachments in the mid symphyseal region. The follow-up was scheduled at 6 and 12 months after implant placement. The patient satisfaction with the denture was evaluated with the visual analog scale (VAS) score. The data obtained were statistically analyzed with the independent student t-test for intergroup comparison and repeated measures of ANOVA followed by Bonferroni's Post hoc analysis for intragroup comparison of mean crestal bone loss at a different time interval. Ten patients each in both the groups were available for follow-up. Crestal bone loss at 6 months follow-up for Dalla Bona group was 0.42 ± 0.10 mm on the mesial side and 0.43 ± 0.14 mm on the distal side and at 1 year 1.54 ± 0.16 mm on the mesial side and 1.66 ± 0.13 mm on the distal side. The mean crestal bone loss at 6 months follow-up for Locator group was 0.48 ± 0.16 mm on the mesial side and 0.45 ± 0.11 mm on the distal side and at 1 year was 1.71 ± 0.22 mm on mesial side and 1.74 ± 0.28 mm on the distal side. There was difference in bone loss at 6 months (mesial: 0.06 mm, p = 0.327; distal:0.02 mm; p = 0.726) and at 1 year (mesial: 0.17 mm, p = 0.063; distal: 0.08 mm; p = 0.423) in between two groups but the difference was statistically insignificant. There was a significant difference found in the VAS score for patient satisfaction with SIMO with Dalla Bona attachments and Locator attachments at 6 months (54.2 vs. 51.8, p = 0.005) and 1 year (60.6 vs. 55.2, p = 0.005). Patient satisfaction with SIMO with Dalla Bona attachments was higher during the follow-up. SIMO with Dalla Bona attachments had less crestal bone loss and less prosthetic complications when compared to Locator attachments, although the difference in the bone loss was statistically insignificant.

Cirolana westbyi, (Isopoda: Cirolanidae) a new species in the ‘Cirolana parva-group’ from the Turneffe Atoll, Belize

ABSTRACT Cirolana westbyi n. sp., a novel species in the ‘Cirolana parva-group’ is described from the Turneffe Atoll, Belize using an integrated molecular and morphological approach. The 18S ribosomal RNA gene for C. westbyi n. sp. and also for Cirolana parva Hansen, 1890 are provided, in addition to new primers, developed for the Cirolanidae 18S gene. The key morphological character for separating C. westbyi n. sp. from other Cirolana is the shape of the uropodal rami: the uropodal endopod is convex on the lateral side while the mesial side is straight. Comparison of the 18S gene shows that C. parva is 95.96% identical to C. westbyi n. sp. across 68% coverage, but due to two unique insertions (‘INS-1’ and ‘INS-2’) into the 18S gene of C westbyi n. sp., which may function as loop regions, they appear to be genetically distinct and different species. This is also supported by phylogenetic analysis, which also highlights some potential paraphyly between the three families, Cirolanidae, Aegidae and Corallanidae. Our morphological description of a new species of cirolanid along with a phylogenetic support using 18S sequence data for species within and around the Cirolanidae, provides greater context for the ‘Cirolana parva-group’. urn:lsid:zoobank.org:pub:71EBBA1C-E82A-4BBE-B567-3FE3359EEFA9

Implant-supported fixed and removable prostheses in the fibular mandible

BackgroundTo restore the health-related quality of life (HRQoL) of patients who underwent jaw resection and reconstruction surgery, dental rehabilitation is an essential procedure and also one of the most challenging for oral and maxillofacial surgeons. Even though recent studies have reported the possibility and reliability of dental implant rehabilitation with the fibula free flap (FFF), clinical reports of long-term follow-up cases are scarce. We herein reported seven cases of FFF reconstruction and implant rehabilitation. We also discussed implant planning strategy and surgical techniques.MethodsFrom 2012 to 2019, seven patients were treated with FFF reconstructive jaw surgery combined with dental implant installation and fabrication of implant-supported prostheses at Seoul National University Dental Hospital, Seoul, Korea. Patient characteristics and FFF treatment results were collected. Records of dental implants were analyzed clinically and radiologically.ResultsAmong the seven patients in this report, there were three males and four females, with an average age of 54.4 years. A total of 39 implants were placed in the fibular bone. The mean follow-up period after implant installation was 24 months. Five implants failed and were removed 3 months after installation. The implant success rate was 87.2%. Marginal bone loss at 12 months after loading was 0.23 ± 0.18 mm on the mesial side and 0.25 ± 0.26 mm on the distal side.ConclusionWith the challenges present in FFF-reconstructed patients, an implant-supported prosthesis is a reliable option for stable and functional oral rehabilitation. The implant-supported prosthesis on the FFF has great results regarding restoration of function (mastication, swallowing, and speaking), appearance, and overall HRQoL. Collaboration between surgeons and prosthodontists is essential for a satisfying outcome.

Third Molar: Optional Tooth

There is always a nagging question, which heightens my curiosity on the appropriate removal of an impacted third molar in this specific situation: What if you have a carious or beyond-repair second molar or second bicuspid? Will you try to heroically upright the mesially and horizontally impacted third molars? How about resorbed second molar or a third molar in close proximity of mandibular inferior alveolar nerve. Uprighting of mesially impacted tilted molars is the recommended treatment and should be done as soon as possible. If not properly corrected, mesially impacted molars may lead to complications such as elongation of opposing teeth, periodontal problems on the mesial side of the affected teeth, caries in the unerupted molars, temporomandibular disorders and poor oral hygiene. Some clinical procedures have been used to upright the third molar. Is it really worth working to leave the third molar be uprighted or have it surgically removed? As most maxillofacial oral surgeons, prefer

Vertical Bone Implant Contact Around Anterior Immediate Implants and Their Stability After Using Either Alloplast or L-PRF or Both in Peri-Implant Gap: A Prospective Randomized Trial.

Various graft materials have been studied for filling peri-implant gap (PIG), but there was no similar randomized clinical trial to evaluate the effect of Platelet-rich fibrin or alloplast or their combination on vertical bone implant contact (BIC) around immediate implants and their stability over a period of 1year. Immediate implants were placed in maxillary anterior region of 30 subjects (n = 10). Either alloplast (group I) or L-PRF (group II) or both (group III) were used to fill the PIG following randomization chart. Vertical BIC was measured on peri-apical radiographs which were taken immediately after placement, after 3, 6 and 12months using Image J software. Periotest was used to measure the implant stability at the time of implant placement, at 3, 6 and 12months after implantation. The comparison of distance from implant shoulder to the first visible bone-to-implant contact (IS-BIC) in each group showed statistically significant bone formation on mesial and distal sides over a 1year period (p < 0.05). There was no significant difference in IS-BIC distance among the three groups at 1year (p > 0.05). Periotest values showed that there was significant improvement in implant stability in all groups in 1-year period. On intergroup comparison, the mean difference of periotest values was statistically non-significant among three groups (p > 0.05). All the graft materials were effective in promoting osseointegration when used as PIG filling materials alone or in combination around immediate implants in maxillary anterior region. REF/2015/06/009200.

New Incision and Flap Designs in Autogenous Bone Ring Grafting with Simultaneous Implant Placement and an Evaluation of the Effect of First-Stage Wound Dehiscence in Dogs

The aim of this study was to explore the effect of preventing first-stage wound dehiscence with new types of incision and flap design and to evaluate the effect of wound dehiscence on the bone resorption of the autogenous bone ring graft. In six beagle dogs, the second and fourth premolars on the bilateral mandible were extracted. After 3 months, on the left extraction sites, conventional alveolar crest incisions were made and the full-thickness flaps were elevated. However, on the right sites, the incisions were made at the mucogingival junction, the split-thickness flaps were elevated toward the lingual side, and the periosteum was elevated toward the buccal side. Then, Straumann implants (. 3.3, length 8 mm) were placed with simultaneous autogenous bone ring grafting. Next, the wounds on the left side were closed with periosteal releasing on buccal flaps conventionally, but the semi-thickness flaps on the right side were sutured with the elevated periosteum. After 3 months, the animals were euthanized, and the harvested samples were analyzed using microcomputed tomography and histology. The incidence rate of wound dehiscence in the new incision group was 16.7%, which was significantly lower than that in the conventional incision group (75%). There was hardly any vertical bone loss of the bone ring in the samples without wound dehiscence, but in wound dehiscence samples, severe bone loss, 2.47 ± 0.17 mm, was found on the buccal side of the bone ring, which was significantly higher than that on the lingual, mesial, and distal sides, 1.37 ± 0.14 mm, 1.00 ± 0.15 mm, and 1.03 ± 0.05 mm, respectively. The use of a mucogingival junction incision and split-thickness flap design can effectively prevent first-stage wound dehiscence in autogenous bone ring grafting, which plays a key role in bone resorption of the graft.

Caries Color, Extent, and Preoperative Pain as Predictors of Pulp Status in Primary Teeth.

AimThis study aimed to assess the relationship between preoperative pain status, caries extent, and caries color and the ability to achieve hemostasis at the canal orifices during pulp therapy access in primary teeth.Study DesignEighty primary molar teeth with extremely deep caries extending to the pulp (based on bitewing radiography) were investigated in 66 children. The teeth with clear radiographic and clinical signs indicating the involvement of the radicular pulp were excluded. The history of preoperative pain status, the color of dental caries by visual inspection, and the extent of caries lesion measured in bitewing radiographs were recorded. After preparing the access cavities, the hemostasis achievement at the canal orifices was assessed and considered as the final factor in determining the type of treatment (pulpotomy or pulpectomy). The data were analyzed using Fisher’s exact test, the independent t-test, and Cohen’s unweighted kappa statistic. P<0.05 was considered statistically significant.ResultsHemostasis was achieved in 78.1% of the teeth with black dental caries, whereas in most of the teeth with light brown dental caries (64.3%), hemostasis was not achieved (p=0.015). The extent of dental caries in the teeth needing pulpotomy was statistically significantly lower than that of those needing pulpectomy (p=0.024). Mesial side dental caries was more related to the irreversible pulpitis compared to the distal one (p=0.01). In 78.1% of the teeth without pain, hemostasis was achieved, and in most of the teeth with nocturnal pain (64.3%), hemostasis did not occur (p=0.034).ConclusionThe caries color, caries extent, and preoperative pain have the potential to be used as clinical diagnostic tools to determine the pulpal status in primary teeth.