Anatomically Driven Immediate Implant Placement in the Esthetic Zone: Two Case Reports as Proof of Principle.

Achieving favorable and stable esthetic outcomes with immediate implants used to replace maxillary anterior teeth can be challenging. Osteotomies need to be initiated along the palatal socket wall, and it is often difficult to stabilize initial drilling. An immediate implant was planned for a hopeless maxillary incisor. Using a flapless surgery technique, the tooth was removed and decoronated, and an entry point was made in the root to guide the osteotomy drills. The root was reinserted and stabilized while a precision drill and 2-mm twist drill were used in sequence to drill through the tooth root, establishing the osteotomy location but stopping 3-4 mm short of final depth. The root was then removed, and the final implant bur for a 3.5 × 11.5-mm implant was drilled to depth, engaging the necessary native bone apically. The original tooth crown was then used to prepare and insert a transitional crown. Reinserting the extracted root of a maxillary anterior tooth and using it as a guide for osteotomy preparation is an excellent method to optimally position an immediate implant palatally in the socket wall.

Long-term results of immediate implantation in mandibular posterior teeth with early loading: A retrospective case series.

When immediate molar implants first were proposed, submerged initial healing and delayed loading were the norm. It is now recognized that some early loading of a nonocclusal nature can stimulate faster osseointegration, although full occlusal loading is still delayed for 3 or more months. Here, we test the hypothesis that earlier occlusal loading of mandibular premolar and molar immediate implants may be possible. In this retrospective case series study, 18 mandibular molar and nine mandibular premolar teeth were atraumatically extracted and immediate implants placed 1-2 mm apical to buccal and lingual crestal bone. Periimplant gaps received particular allograft covered with acellular dermal matrix barrier. Healing abutments were placed through puncture points in the membranes to help in stabilizing the latter and to permit nonsubmerged site healing. At 6-8 weeks, each implant was evaluated for stability using the Periotest® device and restored if the Periotest® (PTV) value seen was negative. Data were analyzed by t test and MannWhitney U at a significance level of P < 0.05. Retrospective assessment of all 27 implants after 5 years' period of follow up showed all implants to have survived. Overall mean crestal bone loss was determined to be-0.25 ± 0.54 mm. Individual mean bone levels for mesial and distal surfaces were-0.24 ± 0.77 mm and-0.26 ± 0.72 mm, respectively (P = 0.78). A statistically significant difference in bone loss between genders was detected. Overall mean probing depth was 2.09 ± 0.57 mm. Based on the widely used Albrektsson criteria, the overall survival and success rate was 100%. Immediate implants placed into mandibular premolar and molar extraction sockets and allowed nonsubmerged healing may be ready for restoration at earlier times than previously thought possible.

Effect of Different Implant-Abutment Mismatches on Stress Distribution: A 3-Dimensional Finite Element Study.

Platform-switching reduces peri-implant marginal bone loss (MBL). The aim of this study was to compare the effect of platform-switching on stress within crestal bone using different implant-abutment mismatches (0.65 and 1 mm) under 2 different vertical loads (30 N vs 200 N) for implants placed in posterior jaw sites. Three-dimensional modeling software was used for an implant with a diameter of 4.5 mm and length of 13 mm. Molars were modeled using computerized tomography images of bone density in human maxilla (D3 bone) and mandible (D2 bone). Collected data were analyzed using CATIA software. In posterior mandible, stress of 30 N force with platform mismatches of 0.65 or 1 mm were 2.920 and 2.440 MPa respectively. Using 200 N force, values increased to 19.44 and 16.30 MPa. In posterior maxilla and 30 N force, stresses with mismatches of 0.65 and 1 mm were 3.77 and 3.18 MPa, respectively, increasing to 25.14 and 20.17 MPa with 200 N force. The effect can be predicted to be greatest as the mismatch increases with implants placed into lower quality bone (posterior maxilla with D3 quality).

A new classification of peri implant gaps based on gap location (A case series of 210 immediate implants).

Based on our collective experiences with gap management around immediate dental implants, we have proposed a classification of gap type based on the location in relation to implant periphery. Seven types are proposed, and all but one type should heal without gap grafting provided that flap-less surgery and atraumatic extraction have been achieved. The exception is our Type II gap where the implant has been placed too far buccally leaving a gap only on the lingual/palatal. In this case, the lingual/palatal gap need not be grafted, but the buccal aspect of the implant should best to augmented to avoid the complications.

CBCT data relevant in treatment planning for immediate maxillary molar implant placement.

Background: This study used CBCT images to evaluate the suitability of maxillary first and second molar sites to receive immediate implants. Buccopalatal and mesiodistal widths of maxillary molar inter-radicular septum were evaluated at three different levels (crestal, middle, and apical), in addition to assessments of the root apex and furcation proximities to the sinus floor and comparisons of these measurements between the first and second upper molar sites before extraction. Methods: A total of 427 dental sites from 223 patients were used to measure the buccopalatal and mesiodistal widths of inter-septal/furcal (IRS) bone of maxillary first and second molars and vertical distances from the furcation and from all the root apices to the sinus floor (SF). Results: Mean coronal-most buccopalatal/mesiodistal IRS widths were 7.33/6.52 mm for the first and 6.86/5.85 mm for the second molars (P=0.008). Corresponding mean FSD (furcation-sinus floor) values were 9.69 mm (range: 2.02-24.68 mm) and 8.84 mm (range: 1.48-25.09 mm). Mean distances from all the root apices to SF were <3 mm. The palatal roots of the first molars had higher sinus intrusion rates (28.85%) than their buccal counterparts, while for the second molars, the mesiobuccal roots showed the highest sinus intrusion (37.65%). Conclusion: In the current patient sample, 61.7% of the first and 34% of the second molars had a sufficiently broad IRS to encase a 5-mm-diameter IMI (immediate molar implant) completely. The mean FSD of 9 mm for both molars indicated that some sinus floor elevation would likely be needed unless short implants were used.

SHELL Part of Nucleus Accumbens and Its Laterality Has Important Role in Response to Chronic Stress in Female Rats

Abstract The nucleus accumbens shell (NAcSh) plays a role in appetitive and negative motivation with sex differences in responses. NAcSh and its laterality in metabolic and hormonal responses to chronic stress in female rats is evaluated via transient inactivation of this nucleus during stress induction. Animals in the stress groups received consecutive stress for four days and transient inactivation of NAcSh was performed by administrating lidocaine (0.2%) unilaterally or bilaterally in the nucleus for five minutes before electric foot shock induction. After stress termination, food and water intake, latency to eat, plasma glucose, corticosterone, estradiol and progesterone were measured in all groups. Results showed that stress increased food intake and blood glucose level, but there were no change in the latency to eat and the amount of water intake. The right side, the left side, and both sides of NAcSh may be dominant in latency to eat, food intake, and both water intake and plasma glucose level, respectively. Although chronic stress included no changes for corticosterone and progesterone, it increased estradiol level in plasma. Also, bilateral and right sides of NAcSh may have modulatory effects on stress in corticosterone and progesterone, respectively, without affecting estradiol. It can be concluded that the NAc shell plays a pivotal role in metabolic and hormonal responses to chronic stress in a laterality manner in female rats.

Effectiveness of buccal pouch grafting in minimizing loss of alveolar dimension: A canine investigation.

BACKGROUND: The study's purpose was to study buccal pouch grafting (BPG) with xenograft, freeze-dried bone allograft (FDBA), or FDBA + decalcified FDBA (DFDBA) on alveolar ridge width preservation and overlying soft tissue thickness at dog premolar extraction sites. MATERIALS AND METHODS: In this animal study, 4 dogs had their mandibular first premolar (P1) and distal roots of P2, P3, and P4 extracted (after endodontic treatment of the mesial roots) bilaterally. A small buccal pouch was created at each extraction socket and four treatments tested: nothing, xenograft, FDBA, or FDBA + DFDBA. Casts made pretreatment and at 1 and 3 months after treatment allowed measurements of buccolingual alveolar ridge width (BLRW), while overlying buccal soft tissue thicknesses were measured clinically. Data were assessed using analysis of variance to compare changes in soft tissue thickness and BLRW between times and treatments. Tukey-Kramer adjustment for multiple comparisons was applied for doing post hoc, pairwise comparisons. Results were considered significant if P < 0.05. RESULTS: Control sites showed significant (P = 0.0067) decreases in soft tissue thickness over time while there was a trend for increased soft tissue thickness at all grafted sites. There were significant losses in BLRW over time for control (P = 0.0032) and FDBA groups (P = 0.015) with a trend for loss with FDBA + DFDBA. Pairwise comparison using Tukey-Kramer adjustment revealed significant increases in BLRW from T1 to T3 for the xenograft group relative to all the others. CONCLUSION: BPG using xenograft is effective in maintaining hard and soft tissue stability following tooth extraction.

The effect of low-level laser 810 nm and light-emitting diode photobiomodulation (626 nm) on the stability of the implant and inflammatory markers interleukin-1 beta and prostaglandin E2, around implants.

BACKGROUND: One of the most common problems in edentulous patients is the low stability of lower dentures. The most effective method to overcome this problem is implant-supported overdentures. After placing an implant, for the process of osseointegration to be complete and successful, it is better that patients do not use their denture for few months. This may be nonconvenient for patient because they are unable to speak and eat properly. The aim of this study was to evaluate the effect of low level laser (LLL) and light-emitting diode (LED) photobiomodulation on implant stability as well as their effect on interleukin-1 beta (IL-1ß) and prostaglandin E2 (PGE2) biomarkers around implant in lower anterior region (over denture). MATERIALS AND METHODS: In this clinical trial, 36 implants were placed in fully edentulous mandibles (12 people per person - three implants in areas of midline and canine). Each of the implants was randomly placed in one of three groups of laser, LED, and control. LLL (power of 50 mw and the amount of 20 J/cm2 for each implant) and LED with dose (20 mw/cm2) were irradiated on the day of surgery (zero), 3, 7, 10, and 14 days. The stability of implants was measured on the day of surgery and weeks 3, 4, and 8 after surgery with Periotest. The inflammatory biomarkers of IL-1ß and PGE2 were also collected from gingival crevicular fluid around implants in 4 and 8 weeks. The collected data were analyzed by ANOVA statistical tests.pvalue<0.05 considered significant. RESULTS: The amounts of Periotest significantly increased 3rd week after surgery in the control group (P < 0.001). However, the laser group and LED group were associated with minimal changes, which indicates lower stability of implant in 3rd week in control group but no changes in stability of test groups (laser and LED). Laser and LED had no effect on the level of IL-1ß and PGE2 in 4 and 8 weeks. CONCLUSION: The use of LLL or LED has a positive effect on the stability of the implants 3 weeks after surgery.

Transient inactivation of the nucleus accumbens (NAc) shell prominently ameliorates responses to acute stress in female rats.

It is clear that the stress response differs between females and males. Moreover, the nucleus accumbens shell is considered a critical area in the brain's response to stress. In the present study we investigate the effect of the transient inactivation of the NAc shell on the metabolic and hormonal disturbance induced by acute stress in female rats. Female Wistar rats were canulated uni- or bilaterally in the NAc shell before stress induction. Electric foot shock was applied to the animals and lidocaine hydrochloride was administered intra-acumbally 5min before each stress session. Food and water intake, delay to eating time, plasma corticosterone, estradiol and progesterone were measured after stress administration. Our results indicate that food intake increased whereas water intake decreased in stress group, furthermore, delay in the onset of eating also was observed. In addition, plasma corticosterone and progesterone concentrations were increased whereas estradiol was decreased. Transient inactivation of right side of NAc shell inhibited the stress effect on food intake; however, the effect of stress was exacerbated when the left part of the NAc shell was inhibited. Transient inactivation of both NAc shell sides augmented the stress effect on water intake. The same results also obtained for the effect of stress on delay to eating time. Lidocaine administration inhibited the effects of stress on all of the hormones we tested. It can be concluded that the NAc shell plays an important role in the mediation of stress responses in female rats and this influence shows asymmetrical manner.

The association between periodontal disease parameters and severity of atherosclerosis.

BACKGROUND: Atherosclerosis is the most common cause for heart attack and stroke. In the last decade, several epidemiological studies have found an association between periodontal infection and atherosclerosis. The aim of this research was to determine the possible association between chronic periodontal disease and severity of atherosclerosis. MATERIALS AND METHODS: Eighty-two subjects that were referred to Chamran Heart Hospital in Isfahan for angiography were involved in this study. Fifty-nine subjects had coronary artery obstruction (CAO) and 23 showed no obstruction after angiography. The severity of CAO was assessed. Periodontal parameters including pocket depth (PD), gingival recession (R), clinical attachment level (CAL), and bleeding on probing (BOP) of all subjects were recorded. The decayed-missing-filled (DMF) index of all subjects was also measured. For statistical analysis, Pearson correlation test, Chi-square, and independent t-test were used. RESULTS: There were significant positive correlation between variables R, PD, CAL, decayed (D), missing (M), DMF, BOP, and degree of CAO. However, there were no significant differences between filling variable degree of CAO (left anterior descending, left circumflex, and right coronary artery). Independent t-test showed that the mean of variables R, PD, AL, D, M, and DMF in patients with obstructed arteries were significantly higher than subjects without CAO. But there were no significant differences between variable F in two groups. CONCLUSION: The results of this cross-section analytical study showed an association between periodontal disease and dental parameters with the severity of CAO measured by angiography. However, this association must not interpret as a cause and effect relationship.

Influence of motion pattern on apical transportation and centering ability of WaveOne single-file technique in curved root canals.

BACKGROUND: The aim of this study was to evaluate apical transportation and centering ability of single-file instruments, WaveOne primary, with full rotation versus reciprocation movement using cone-beam computed tomography (CBCT) analysis in curved mesiobuccal (MB) root canal of human mandibular molars. MATERIALS AND METHODS: Thirty MB canals of mandibular molars were randomly divided into two groups according to the instrument motion (n = 15): Group 1, reciprocation/WaveOne primary; Group 2, continuous rotation/WaveOne primary. After preparation, the amount of apical transportation and centering ability were assessed by evaluating pre- and post-instrumentation CBCT scans in three section (1, 3, and 5 mm from apical foramen). Statistical analysis of the data was performed using Mann-Whitney U-test and Friedman test (α = 0.05). RESULTS: There was no statistically significant difference between two experimental groups in terms of apical transportation and centering ratio at 1, 3, and 5 mm from apical foramen (P > 0.05). CONCLUSION: Apical transportation and centering ability of WaveOne primary reciprocating instrument did not significantly differ between two motion patterns.

A Systematic Review of Outcomes Following Immediate Molar Implant Placement Based on Recently Published Studies.

BACKGROUND: Immediate implant placement in molar extraction sites has become a treatment option for experienced clinicians. PURPOSE: The aim of this study was to provide a systematic review and meta-analysis of outcomes from recent clinical studies with immediate molar implants. MATERIALS AND METHODS: A systematic review was undertaken of relevant literature published from November 2008 to May 2015. Data collected included implant survival rates after at least 1 year in function, cumulative crestal bone loss, and implant location (maxilla vs mandible) and diameter. Implant diameters were grouped as "wide" (4-6 mm) or "ultra-wide" (>6-9 mm). Survival and bone loss with 95% CIs were calculated using a random effects model. Meta-analysis techniques were used to compare survival rates and cumulative mean bone loss between immediate and delayed placement implants. Survival rates also were computed and compared between wide and ultra-wide implants using chi-square testing. The quality of each study was assessed using established criteria. RESULTS: The literature search provided 15 papers published between November 2008 and May 2015 that satisfied the inclusion criteria. Data on survival were found for a total of 768 immediate molar implants inserted in 757 patients. Meta-analysis of these data showed an implant survival rate of 98% with no difference between maxilla and mandible. Five studies included delayed molar implants as controls, and no significant differences were detected. A significant difference (p = .048) was found in relation to implant diameter with implant failures being higher (3.67 vs 1.45%) for ultra-wide (>6-9 mm) versus wide (4-6 mm) implants. The majority of the 15 studies were determined to be either "average" (prospective case series) or "fair" (retrospective) in quality. CONCLUSION: While there are still no published reports from double-blind, randomized, controlled (best quality) clinical trials of immediate molar implant placement, high survival rates have been reported. The present data, however, suggests that there may be an optimal diameter for this implant application. Meta-analysis of the limited bone loss data reported estimated the overall mean cumulative bone loss after at least 1 year to be 0.57 mm.

Alterations of the Danger Zone after Preparation of Curved Root Canals Using WaveOne with Reverse Rotation or Reciprocation Movements.

INTRODUCTION: The aim of this study was to compare the changes that occur in the danger zone (DZ) after preparation of curved mesiobuccal (MB) canals of mandibular first molars with WaveOne instruments in two different movements [reciprocation (RCP) and counter-clockwise rotation (CCWR)] by means of cone-beam computed tomography (CBCT). METHODS AND MATERIALS: MB canals of 30 mandibular molars were randomly divided into 2 groups (n=15); WaveOne/RCP and WaveOne/CCWR. Pre- and post-instrumentation CBCT images were assessed for changes in the dentin thickness in DZ (2 and 4 mm below the highest point of the root furcation) in both groups. Data was analyzed using the repeated measures ANOVA test. RESULTS: There was no statistically significant difference between two experimental groups in terms of remaining dentin thickness at 2 and 4 mm levels below the highest point of the furcation (P>0.05). CONCLUSION: The efficacy of WaveOne instrument on changes of the dentin thickness in the DZ was not affected by different file movements.

Keratoameloblastoma, a very rare variant of ameloblastoma.

The keratoameloblastoma is a rare histologic variant of ameloblastoma. Fewer than 15 cases of keratoameloblastoma have been documented in the literature. We report a new case of keratoameloblastoma in a 21-year-old female patient with a unilocular radiolucent lesion between the roots of the right mandibular incisors. We describe the clinical, radiographic, and histopathologic features of this lesion along with a review on the characteristics of previous cases. We also discuss about classification and management of this lesion.

The effects of laser microgrooves on hard and soft tissue attachment to implant collar surfaces: a literature review and interpretation.

This paper summarizes current knowledge on the benefits of laserablated microgrooves in neck regions of endosseous dental implants. Like machine-tooled coronal microthreads with particle-blasted surfaces, laser-ablated microgrooves help to preserve crestal bone. However, they also appear to uniquely favor a true gingival connective tissue attachment comparable to that of natural teeth.

Influence of local anesthetics with or without epinephrine 1/80000 on blood pressure and heart rate: A randomized double-blind experimental clinical trial.

BACKGROUND: Local anesthesia (LA) with epinephrine have an important role in pain and bleeding control. However, most clinicians believe LA + epinephrine may cause rapid raise in blood pressure (BP) and heart rate (HR). The aim of this research was to compare the changes in HR and BP after administration of lidocaine with and without epinephrine 1/80000 in two infiltration (INF) and inferior alveolar nerve block methods (IANB). MATERIALS AND METHODS: The study was a randomized double-blind experimental clinical trial. Forty subjects were divided into two equal groups and two subgroups. In one group, INF and in the other group, IANB were used and, further, in one subgroup lidocaine and in another subgroup, lidocaine plus epinephrine were used. BP and HR were recorded before and 10 min after. The paired t-test for intragroup differences and independent t-test for intergroup analysis were used at the significant level of P≤0.05. RESULTS: The mean BP and HR values were reduced after injection of lidocaine in both INF and IANB compared with baseline. The differences were statistically significant (P < 0.05), but, on comparing these values between the two injection methods, the differences were not statically significant (P = 0.089 and 0.066, respectively). The mean BP and HR values were increased after injection of lidocaine plus epinephrine in both INF and IANB compared with baseline, and these were statistically significant (P < 0.05) but, on comparing these values between the two methods, the differences were not statically significant (P = 0.071 and 0.092, respectively). CONCLUSION: The rise in BP and HR following injection of lidocaine plus epinephrine was statistically significant compared with baseline in both INF and IANB, but this was not clinically and numerically considerable.