Evaluation of the efficacy of celecoxib and ibuprofen on postoperative pain,swelling, and mouth opening after surgical removal of impacted third molars: a randomized,controlled clinical trial

The objective of this study was to compare the efficacy of celecoxib and ibuprofen in reducing postoperative sequelae following the surgical removal of impacted mandibular third molars. Ninety-eight subjects who needed surgical extraction of an impacted mandibular third molar were selected for the study. All subjects were randomly allocated to receive one of the following treatments twice a day for 5 days after surgery: placebo (n = 32), ibuprofen (n = 33), or celecoxib (n = 33). The primary outcome chosen was postoperative pain, which was evaluated using the visual analogue scale (VAS) score recorded by each patient. The secondary outcomes chosen were changes in postoperative swelling and maximum mouth opening values compared to preoperative ones. Compared to placebo, treatment with celecoxib and ibuprofen resulted in improvements in the primary outcome. Furthermore, when compared to the other groups, patients in the celecoxib group showed a significant reduction in postoperative pain scores at 6 h (P < 0.001), 12 h (P = 0.011), and 24 h (P = 0.041) after surgery. Regarding swelling and maximum mouth opening values, there were no significant differences between the groups at each follow-up session. This study demonstrated that treatment with celecoxib decreased the incidence and severity of postoperative pain following third molar surgery compared to ibuprofen and placebo.     

Groningen temporomandibular total joint prosthesis: An 8-year longitudinal follow-up on function and pain

Total temporomandibular joint replacement is a surgical procedure for patients with severe temporomandibular joint afflictions affecting quality of life, which have not responded beneficially to previous conventional surgery. The aim of this study was to assess the long-term outcome of the Groningen temporomandibular joint (TMJ) prosthesis in patients with chronic pain and mutilated temporomandibular joints following multiple surgical procedures, with respect to prosthesis failure, the patient's postoperative level of satisfaction and longitudinal changes in maximum mouth opening, functional mandibular impairment and pain. Eight female patients were studied in whom Groningen TMJ prostheses were inserted, two unilaterally and six bilaterally.The Groningen TMJ prosthesis was mechanically successful during 8 years of follow-up in seven out of eight patients with a disc dislocation being seen in one patient (7%). Patients were satisfied, despite the limited improvement of the maximum mouth opening, and pain scores.Although the decline of MFIQ scores during 8 years of follow-up was significant compared to baseline (p = 0.027), the effects of the prosthesis on maximum mouth opening, function and pain were limited. This may be due to persistent chronic pain and the adverse effects of multiple previous surgical procedures.     

Evaluation of fit feasibility of stock total joint replacement in temporomandibular joint ankylosis patients

Long standing adult temporomandibular joint ankylosis (TMJA) results in smaller ramal height, and warped and undulated ramus. Despite the efforts made to standardise the sizes available in stock joint (Zimmer Biomet®), the system causes fit challenges in TMJA patients. The aim of the study was to evaluate the virtual feasibility of stock prostheses in TMJA patients. The data included amount of bone contouring for fossa placement, available ramal length, length discrepancy if placed straight, angulation of mandibular component required to adapt to the bone, and mediolateral fit discrepancy. CT data of 50 TMJA patients (71 joints; unilateral, n = 29; bilateral, n = 21; male, n = 33; female, n = 17) with mean age of 24.26 ± 8.88 years were included. 53 joints required more than 3 mm lateral bone reduction for fossa placement. The ramal length were categorised into ranges 35–40 mm (n = 15), 41–45 mm (n = 14), 46–50 mm (n = 28) and >50 mm (n = 14). Correlation between the age of occurrence of ankylosis and ramal length using the Pearson correlation coefficient revealed a positive correlation (r = 0.38, p = 0.001). Length discrepancy, angulation of mandibular component, and mediolateral fit discrepancy decreases as the ramal length increases. Only 14 joints had appropriate fit of stock prostheses while the remaining 57 joints warranted compromised placement. Even the smallest available stock mandibular component (45 mm) had a compromised fit in terms of length and adaptability on the lateral aspect of ramus. The study concludes that a short ramus is mostly limiting factor in using stock prosthesis in TMJA patients. There is a need for still smaller size stock prostheses.     

Comparison of the outcomes of three surgical treatments for end-stage temporomandibular joint disease

The aim of this study was to determine whether there are any differences between condylectomy, rib grafts, and prosthetic joints (Biomet TMJ stock prosthesis) with regard to outcomes for patients with end-stage temporomandibular joint (TMJ) disease. Fifty-six of a total 127 patients who presented with category 5 end-stage TMJ disease over 3 years (2010–2013) agreed to participate in this retrospective, comparative, cohort study. Patients were divided into four groups: preoperative (n = 16), condylectomy (n = 8), rib graft (n = 16), and prosthetic joint (n = 16). They were assessed for major postoperative complications (i.e., return to theatre) and maximum range of mandibular motion, and all completed a specific quality of life (QOL) questionnaire. Whilst the condylectomy group demonstrated the best mandibular range of motion (P < 0.01), rib graft patients were more likely to experience complications (43.8%) necessitating a return to theatre. The prosthesis group recorded the best mean aggregate QOL score, but the difference compared to the rib graft and condylectomy groups was not statistically significant. The results of this study suggest that for dentate patients, prosthetic joints are highly dependable with no returns to theatre and favourable QOL outcomes. For edentulous patients, condylectomies alone also appear to work well. Future TMJ prosthetic designs should focus on improving mandibular range of motion, as the current stock prosthesis allows only a restricted range, no better than that achieved with rib graft (P > 0.05) and far less than that achieved with condylectomy (P < 0.01).     

“A comparative evaluation between single noncompression titanium miniplate and three dimensional titanium miniplate in treatment of mandibular angle fracture” – A randomized prospective study

PurposeThe aim of this study was to compare efficacy between the single non-compression titanium miniplate and single three-dimensional titanium miniplate in mandibular angle fracture treatment.Method and materialsA prospective study of 20 patients with mandibular angle fractures. Patients were randomly categorized into two groups with 10 patients in each group. Group-I patients were treated with single 2.0 mm conventional titanium miniplate, Group-II patients were treated with single 2.0 mm three-dimensional titanium miniplate according to Champy's principles. Parameters such as stability of fracture fragments, occlusion, mouth opening, additional fixation required and complications were evaluated at different time intervals.ResultsIn Group-I, about 40% (n = 4) of patients showed unstable fracture fragments on immediate postoperative day whereas in Group-II only 10% (n = 1) of patients with fracture instability. In Group-I, 30% (n = 3) had mild occlusal derangement and 20% (n = 2) had deranged occlusion on immediate postoperative day, where as in Group-II only 20% (n = 2) of patients had mild occlusal derangement. Additional fixation required in 30% (n = 3) of patients in group-I, and 10% (n = 1) in Group-II. 20% (n = 2) of patients in Group-I developed infection. All patients in both the groups had inadequate mouth opening on immediate post operative day, later resumed normal mouth opening. 10% (n = 1) in group-I and 20% (n = 2) of patients in group-II presented with postinjury/preoperative inferior alveolar nerve sensory disturbance with no incidence of postoperative sensory disturbance. None of the patients in both the groups had malunion, nonunion, plate fracture, and loosening of plates and screws.Conclusion3-D titanium miniplates showed more favorable results compared to single conventional titanium miniplate with respect to initial interfragmentary stability and complications.     

Neurosensory assessment in patients with total reconstruction of the temporomandibular joint

Somatosensory sensitivity and postoperative endogenous pain modulation have not been investigated in temporomandibular joint (TMJ) prosthesis patients. The objectives of this study were to assess somatosensory function at the TMJ and examine possible differences in conditioned pain modulation (CPM) between patients with total TMJ prostheses (n = 7) and a reference group of healthy controls (n = 20). Somatosensory abnormalities were assessed using quantitative sensory testing (QST), which encompasses thermal and mechanical testing procedures. CPM was tested by comparing pressure pain thresholds (PPT) before (baseline), during, and after the application of painful and non-painful cold stimuli. PPTs were measured at the TMJ and thenar eminence (control). The effect of CPM on PPT values was tested with analysis of variance. Three patients exhibited mixed somatosensory loss (i.e., decreased thermal and mechanical detection) with mixed hyperalgesia (i.e., increased sensitivity to thermal and mechanical pain) and two patients exhibited mixed loss with only mechanical hyperalgesia. There was a significant decrease in pressure pain sensitivity at both sites during painful cold application in healthy controls (P < 0.001) but not in patients (P = 0.476). In conclusion, QST measures demonstrated somatosensory abnormalities in patients with total TMJ prostheses. Noxious conditioning cold stimuli evoked CPM-like effects in healthy subjects but not in patients with TMJ reconstruction.     

Sliding contact wear and subsurface damage of CAD/CAM materials against zirconia

ObjectiveMost previous work conducted on the wear behavior of dental materials has focused on wear rates and surface damage. There is, however, scarce information regarding the subsurface damage arising from sliding contact fatigue. The aim of this study was to elucidate the wear mechanisms and the subsurface damage generated during sliding contact fatigue in 5 contemporary CAD/CAM materials against a zirconia indenter.MethodsForty discs (Ø12 mm, 1.55 mm thick) were cut out of IPS e.max CAD (e.CAD), Suprinity PC (SUP), Enamic (ENA), Vitablocs Mark II (VMII) and Lava Ultimate (LU) blocks and mirror polished. After cementation onto a dentin-like composite, off-axis mouth-motion cycling was conducted with a spherical zirconia indenter (r = 3.18 mm) in water (200 N load, 2 Hz frequency) for 5 different cycling periods (10², 10³, 10⁴, 10⁵, 10⁶ cycles, n = 8). Analysis of the wear scars was conducted using light-microscopy, scanning-electron-microscopy and optical profilometry. Subsurface damage was assessed using sagittal and transverse sections of the samples.ResultsFatigue wear mechanisms predominated in glassy materials (e.CAD, SUP, VMII), accompanied by extensive subsurface damage, whereas abrasive wear mechanisms were responsible for the large wear craters in the resin composite (LU) with an absolute absence of subsurface fracture. A combination of both mechanisms was observed in the polymer-infiltrated reinforced-glass (ENA), displaying large wear craters and severe subsurface damage.SignificanceWell-controlled laboratory simulation can identify wear and subsurface damage susceptibility of various classes of restorative materials. Both wear and subsurface fracture are determining factors for the long-term success of restorations.     

Strategies to reduce re-ankylosis in temporomandibular joint ankylosis patients

The purpose of the study was to define a protocol for the prevention of re-ankylosis after surgical management of temporomandibular joint ankylosis (TMJA). The investigators designed a retrospective study on all TMJA patients treated with different treatment modalities from 2013 to 2019. The investigators observed that complete removal of the ankylotic mass particularly on the medial side; use of a piezoelectric scalpel for a clean and smooth osteotomy with copious irrigation to remove bone chips and slurry; less trauma to the local tissue; osteotomy design parallel and inferior osteotomy at the narrowest part, which mostly corresponds to the condylar neck; performance of a coronoidectomy (if mouth opening is <30 mm), fat interposition; no intraoperative correction of any pre-existing chin deviation when treated with costochondral graft; patient motivation; and aggressive physiotherapy, and use of a vacuum drain are all important to prevent re-ankylosis, irrespective of the treatment modality. A total of 114 patients (n = 152 joints), [bilateral (n = 38), unilateral (n = 76)] were evaluated retrospectively. Interpositional arthroplasty with fat was performed in n = 43, CCG was used for reconstruction in n = 30 and total joint replacement (TJR) was done in n = 41 patients. Re-ankylosis was seen in n = 3 (2.6%) patients (2 in CCG and 1 patient in interpositional arthroplasty). The follow-up ranged from 12-80 months. The results conclude that following the suggested best practice protocol is effective in reducing re-ankylosis.     

Treatment modalities of TMJ ankylosis: experience in Delta Nile,Egypt

The study reports the authors’ experience in managing TMJ ankylosis in Delta Nile, Egypt (1995–2006) and compares the surgical modalities used. 101 patients (109 joints) were reviewed in this retrospective study. Pre- and postoperative assessment included history, radiological and physical examination, and mouth opening. Age, sex, aetiology, joint(s) affected, surgical modality, complications and follow up periods were evaluated. Various types (fibrous, fibro-osseous and bony) of TMJ ankylosis were diagnosed; trauma was the commonest aetiology. The patients’ age range was 2–41 years, 62% were female, and the follow up period ranged from 14 to 96 months. Average mouth opening was significantly increased from 5.3 mm pre-operatively to 32.9 mm 12 months postoperatively (P = 0.0001). Marked improvement in mouth opening was documented when the ramus-joint complex was reconstructed using distraction osteogenesis (34.7 mm), costochondral graft (34.4 mm) and Surgibone (34.6 mm). Gap arthroplasty showed least satisfactory mouth opening compared with other techniques (P = 0.001). Minor and major complications were encountered in 33% of cases, including 5% recurrence rate. Early release of TMJ ankylosis; reconstruction of the ramus height with distraction osteogenesis or bone grafting combined with interpositional arthroplasty, followed by vigorous physiotherapy is successful for managing TMJ ankylosis.     

Sensory purinergic receptor P2X3 is elevated in burning mouth syndrome

Recent studies show that P2X₃ may play a role in neuropathic pain, including orofacial pain. Burning mouth syndrome (BMS) is a chronic neuropathic pain condition affecting 0.6–12% of post-menopausal women in the Western world. This study evaluates, for the first time, P2X₃ immunoreactivity levels in lingual mucosa in BMS patients. Patients diagnosed with BMS (n = 9) in accordance with International Association for the Study of Pain criteria and patients attending for wisdom tooth removal (n = 10, controls), were involved in this study. A pain history and score was recorded on a visual analogue scale (VAS) prior to obtaining a lingual biopsy. Immunohistochemistry and image analysis were used to quantify submucosal nerve fibres expressing P2X₃ and the structural marker neurofilaments. P2X₃ positive fibres were significantly increased in BMS compared with controls (p = 0.024). In contrast, neurofilament-staining fibres were reduced in BMS, and when expressed as a ratio of the neurofilament percentage area, there was a trend for an increase of P2X₃ positive fibres in the BMS group. Increased P2X₃ immunoreactivity in the trigeminal sensory system may play a role in the symptoms observed in BMS. P2X₃ may therefore be a therapeutic target for treating BMS and trigeminal neuropathic pain.     

In vitro longitudinal evaluation of enamel wear by cross-polarization optical coherence tomography

ObjectivesEnamel thickness determination by Cross-Polarization Optical Coherence Tomography (CP-OCT) is a promising approach for quantitative monitoring of tooth wear progression. This study evaluated the ability of CP-OCT to quantify the thickness of natural enamel before, during and after tooth wear simulation.Materials and MethodsNatural, unpolished human dental enamel slabs were submitted to five wear stages (Wear 1: to level the surfaces; Wear 2 to Wear 5: 0.05 ± 0.02 mm reduction each) simulated by an automatic grinding/polishing machine. Enamel thickness was evaluated with CP-OCT and a gold-standard method (micro-CT) at baseline and after every wear stage. Data were analyzed using ANOVA with pairwise comparisons for wear stages’ impact on the thickness and wear depth measurements. The inter-method agreement was analyzed using intra-class correlation coefficients, the difference between means, and Bland-Altman plots.ResultsEnamel thickness measurements (mean ± standard error, in mm) with natural (1.40 ± 0.05) and worn surfaces (1.08 ± 0.02) by CP-OCT did not differ significantly from those measured by micro-CT (natural = 1.39 ± 0.05; worn = 1.09 ± 0.02; p-values = 0.30 and 0.39, respectively). CP-OCT and micro-CT showed excellent agreement on natural (ICC = 0.98) and worn surfaces (ICC = 0.98) enamel thickness measurements. Among and between wear stages, there were significant differences in enamel thickness and wear depth measurements for both methods (p-value <0.0001 for all). Both methods yielded similar measurements’ mean (0.14 ± 0.01; p-value = 0.87) and were in good agreement (ICC = 0.77) for wear depth estimation.SignificanceCP-OCT allows accurate measurement of enamel thickness on natural tooth surfaces. Enamel thickness measurement by CP-OCT allows quantitative monitoring of enamel thickness changes and wear depth following progressive wear.     

PainDETECT: a suitable screening tool for neuropathic pain in patients with painful post-traumatic trigeminal nerve injuries?

The PainDETECT questionnaire (PD-Q), originally developed and validated in a multicentre study of neuropathic pain (NeP) patients with back pain, is increasingly being applied to other pain conditions. The present study assessed whether the PD-Q would be a suitable screening tool for detecting NeP in patients with post-traumatic inferior alveolar nerve injury (IANI) and lingual nerve injury (LNI). A prospective cohort of patients with clinically diagnosed neuropathy was given the PD-Q at their clinic appointment, or it was sent to them after their consultation. Eighty-nine patients (IANI = 56, LNI = 33) were included in the study, 75 of whom suffered from painful neuropathy. Of the patients who completed the questionnaire fully (n = 56), allowing a summary score to be calculated, 34% were classified as having ‘likely NeP’ according to the PD-Q; 41% of patients scored in the uncertain classification range and the remaining quarter in the ‘likely nociceptive’ classification. There was a significant association between PD-Q scores and pain intensity levels across the sample, with those classified as likely NeP reporting high levels of pain. The results suggest that the PD-Q in its current format is not a suitable screening tool for NeP associated with IANI or LNI.     

Fracture loads of screw-retained implant-supported zirconia prostheses after thermal and mechanical stress

PurposeThe objective of the present study was to evaluate fracture loads of screw-retained implant-supported zirconia prostheses after artificial aging.MethodsFour types of screw-retained implant-supported prostheses were fabricated (n = 11 each); porcelain-veneered zirconia prosthesis (PVZ), indirect composite-veneered zirconia prosthesis (IVZ), porcelain-fused-to-metal prosthesis (PFM), and monolithic zirconia prosthesis (ML). The specimens were subjected to 10,000 thermocycles and cyclic loading for 1.2 million cycles. Fracture loads were measured, and the data were analyzed with the Kruskal–Wallis and Steel–Dwass tests (α = 0.05).ResultsAll specimens survived the artificial aging procedures. The fracture loads for the PVZ (1.52 kN), IVZ (1.62 kN), and PFM groups (1.53 kN) did not significantly differ; however, the fracture load for the ML group (6.61 kN) was significantly higher than those for the other groups. The fracture load for the IVZ group was comparable to those for the PVZ and PFM groups.ConclusionsThe monolithic zirconia prostheses exhibited significantly higher fracture loads than the bilayered prostheses. All the investigated types of screw-retained implant-supported zirconia prostheses appear sufficient to resist posterior masticatory forces during long-term clinical use.     

Prospective study of five-year outcomes and postoperative complications after total temporomandibular joint replacement with two stock prosthetic systems

To evaluate and compare outcomes and complications associated with reconstruction of the temporomandibular joint (TMJ), we prospectively analysed the data of 70 patients who had their joints replaced with stock prostheses during the period 2004-14 and who had been followed up for five years. We used two types of stock prostheses: the metal-on-metal Christensen system (CS), and the ultra-high-molecular-weight-polyethylene-on-metal Biomet® system (BS). Data were collected at 3, 6, 12, 24, 36, 48, and 60 months postoperatively and compared with preoperative measurements. Five years after the replacement there was an increase in mean (SD) mouth opening from 2.0 (0.6) to 4.0 (0.5 cm) (p = 0.012) in the CS, and from 2.5 (1.0) cm to 4.1 (0.6) cm (p = 0.018) in the BS. The mean (SD) reductions in visual analogue pain scores were from 6.9 (1.6) to 2.0 (1.4) (p = 0.001) in the CS, and 6.5 (1.4) to 1.5 (1.1) (p = 0.001) in the BS. There were no significant differences in improvements in mouth opening or reduction in pain between the two groups. However, there were differences in the number of implants that failed, which led to removal and replacement of 2/14 prostheses in the CS group and 3/77 in the BS group (p = 0.06). The results supported the placement of stock prostheses, as evidenced by a low incidence of complications and adverse events, and a long-term improvement in function and reduction in pain in the TMJ. The BS group had significantly fewer prosthetic failures than the CS group.     

Middle mesial canals in mandibular first molars: A micro-CT study in different populations

ObjectiveTo describe the morphological aspects of middle mesial canals (MMC) in mandibular first molars using micro-CT.DesignMandibular first molars collected from the Brazilian (n = 136) and Turkish (n = 122) populations were scanned (voxel size: 9.9 μm) and mesial roots with MMC (n = 48) evaluated regarding several morphological aspects. The incidence of MMC in each population was statistically compared using Chi-square test (α = 0.05).ResultsOverall, the incidence of MMC was 18.6% (48 out of 258 molars) and was significantly higher in the Brazilian (n = 30; 22.1%) than in the Turkish (n = 18; 14.8%) population (p < 0.05). In both populations, confluent configuration of the MMC was the most frequent anatomy. Most of the specimens with MMC had 3 independent orifices (n = 26; 54.2%) and 3 apical foramina (n = 21; 43.8%). The mean minor diameter of the MMC orifice (0.16 mm) was 3 times less than the other orifices (∼0.50 mm). In mesial roots with independent configuration (n = 3; 6.3%), the mean volumes (mm³) of the MMC, mesiobuccal (MBC) and mesiolingual (MLC) canals were 0.20 ± 0.10, 0.75 ± 0.28, and 0.88 ± 0.19, respectively. In the specimens with canal confluence (n = 26; 54.2%), MMC merged to the MBC (n = 8; 16.7%), MLC (n = 4; 8.3%), or to both MBC and MLC (n = 14; 29.2%). Double mesial canal was observed in only 1 specimen. MMC with an independent foramen was observed mostly in Brazilian specimens.ConclusionsIncidence of MMC was higher in the Brazilian molars. Confluent configuration was the most prevalent anatomic variation, while independent and fin configurations, as well as, double MMC, were found only in a few specimens.     

Comparative study of the effect of warm saline mouth rinse on complications after dental extractions

The aim of the present study was to determine the effect of saline mouth rinse on postoperative complications following routine dental extractions. Patients aged ≥16 years, who were referred to the oral surgery clinic with an indication for non-surgical extraction of pathologic teeth, were prospectively and uniformly randomized into three groups. Group A (n = 40) were instructed to gargle six times daily with warm saline and group B (n = 40) twice daily; group C (n = 40) were not instructed to gargle with warm saline and served as controls. Information on demographic characteristics, indications for extraction, and the development of complications, such as alveolar osteitis, acute inflamed socket, and acute infected socket, was obtained and analyzed. There were no significant differences between patients who gargled six times daily with warm saline and those who gargled twice daily with reference to either alveolar osteitis or acute inflamed socket (P > 0.05). However saline mouth rinses at either frequency were beneficial in the prevention of alveolar osteitis in comparison with those who did not rinse. A twice-daily saline mouth rinse regimen is more convenient, and patient compliance may be better than with a six times daily rinse regimen.     

Is dermis fat arthroplasty better than plain gap arthroplasty? A prospective randomised controlled trial

The aim of the study was to compare interpositional arthroplasty using a dermis fat graft with gap arthroplasty in the management of ankylosis of the temporomandibular joint (TMJ). We organised a prospective randomised study of 22 patients who presented with ankylosis of the TMJ. They were randomised to be treated with either plain gap arthroplasty or dermis fat arthroplasty, and the predictor variable was the method of treatment. The primary outcome variables were mouth opening and pain on jaw exercises. Pain and interincisal opening were measured on day 5, day 14, at the end of one month, and at six months, one year, two years, and three years. There was a significant difference between the two groups on two occasions: postoperative day 5 (p = 0.013) and at one year (p = 0.018). The mean (SD) scores for mouth-opening were higher in the dermis fat group at all times (41.20 (4.69) mm compared with 39.50 (2.46) mm in gap arthroplasty at two years, and 41.40 (3.60) mm compared with 38.9 (2.02) mm at three years). The visual analogue pain scores were also lower in the dermis fat graft group. The groups showed similar results at the end of three years follow up, with no significant difference in mouth opening. We conclude therefore that the two techniques have similar outcomes in the management of ankylosis of the TMJ.     

Short-term use of an exposed polypropylene barrier in the preservation of alveolar bone after extraction: randomized clinical trial

This study was performed to evaluate the short-term preservation of alveolar bone volume with or without a polypropylene barrier and exposure of the area after extractions. Thirty posterior tooth extraction sockets were distributed randomly to a control group (n = 15; extraction and suture) and a barrier group (n = 15; extraction, barrier, and suture). All sutures and barriers were removed 10 days postoperatively. Cone beam computed tomography scans taken with the aid of a tomographic guide were obtained preoperatively, immediately postoperative, and at 120 days postoperative. A visual analysis of the coronal sections of the alveolus was performed, and vertical loss in the mesial, distal, buccal, and lingual bone ridges and horizontal thickness were evaluated. The mean vertical loss after extraction did not differ significantly between the control and barrier groups (Student t-test: mesial P =  0.989, buccal P =  0.997, lingual/palatal P =  0.070, distal P =  0.107). The mean vertical loss at 120 days postoperative did not differ significantly between the control (0.65 mm) and barrier (0.52 mm) groups (P >  0.05), with an effect size of 0.13 mm. At 120 days, the barrier group presented a mean resorption in thickness (0.45 mm) that was significantly lower than that in the control group (0.76 mm) (P =  0.021), with an effect size of 0.31 mm. The polypropylene barrier reduced the horizontal resorption in sockets of posterior teeth after extraction.     

The ability of orthodontists and laypeople to discriminate mandibular stepwise advancements in a Class II retrognathic mandible

ObjectivesThis study analysed the ability of orthodontists and laypeople to discriminate mandibular stepwise advancements.Materials and methodsFour pictures (in duplicate) were taken of a male patient with Class II malocclusion and mandibular deficiency with the mandible positioned in habitual maximum intercuspation (HMI) and with stepwise advancements of 2 mm, 4 mm and 6 mm. These images were examined by orthodontists (n = 30) and laypeople (n = 30). The Wilcoxon signed-rank test was used to evaluate intra-examiner agreement. Intra-examiner ability to discriminate stepwise mandibular advancements was examined by Friedman's test. A Mann-Whitney's test was carried out to analyse score difference between orthodontists and laypeople. Type I error (alpha) was set as 5% for all statistical tests.ResultsWe observed a satisfactory to excellent level of methodological reliability. While laypeople were able to notice mandibular advancements ≥4 mm (p<0.05), orthodontists were able to observe mandibular advancements ≥2 mm (p<0.05). The orthodontists were more critical than laypeople with regard to the facial profile evaluation when facial convexity increased (p<0.001), but no significant difference was observed when the sagittal maxillo-mandibular relationship approached normality (p<0.05).ConclusionsConsidering that the mean sagittal mandibular growth due to the use of functional orthopaedic appliances is reported in the literature as 2 mm, it seems that laypeople may not able to discriminate this amount of change in facial-profile attractiveness.