[Comparison of clinical esthetic effects of two abutments of maxillary anterior dental implants with single crown].

Objective: To compare and evaluate the clinical esthetic effect of angle screw channel abutment and personalized zirconia adhesive abutment for single crown restoration in esthetic area. Methods: A total of 44 patients (21 males and 23 females), aged (37.4±13.5) years (18-67 years) who completed single crown restoration in the esthetic area of the Department of Oral Implantology, Dalian Stomatological Hospital from January 2018 to June 2022 were retrospectively selected. A total of 44 implants were inserted. According to the abutment selected for final restoration, the patients were divided into angle screw channel abutment group and personalized zirconia bonding abutment group, with 22 patients and 22 implants in each group. The implant survival rate, complication rate, pink and white esthetic score and marginal bone resorption were compared between the two groups. Results: Follow-up to 12 months after final restoration, implant survival rates were 100% (22/22) in both groups, and there was no statistically significant difference in the incidence of mechanical complications between the two groups [9% (2/22) in the angle screw channel abutment group and 0(0/22) in the personalized zirconia bonding abutment group, χ2=2.10, P=0.148]. In the follow-up appointment 12 months after final restoration, the pink esthetic score of the angle screw channel abutment group (12.95±1.05) was significantly better than that of the personalized zirconia bonding abutment group (11.45±2.02) (t=3.10, P=0.003). There was no significant difference in white esthetic scores between the two groups (t=1.27, P=0.212). There was no significant difference in the marginal bone resorption between the two groups (t=0.32, P=0.749). Conclusions: When a single implant supported restoration is delivered in the esthetic area of the anterior maxilla, high implant survival rate and stability of the marginal bone can be obtained by using the angle screw channel abutment or the personalized zirconia bonding abutment. The clinical efficacy of the angle screw channel system is reliable, and it will provide clinicians with a new treatment option.

Clinical Outcomes of Dental Implant Fractures: A Case Series and Analysis of Influencing Factors.

OBJECTIVE: To observe and analyse patients with dental implant fracture and explore the factors influencing the fracture with the aim of providing reference for physicians' clinical work. METHODS: The clinical data of 19 patients with dental implant fracture who visited the Department of Implantology of our hospital between 2007 and 2019 were retrospectively observed and analysed, and the fracture's influencing factors (e.g. the fracted implant site, implant diameter and connection mode, upper prosthetic method and fracture site) were analysed and investigated. RESULTS: The fractured implants comprised 12 Straumann implants (5 fractured at the smooth dental neck and 7 atop the central screws), 5 Bego implants (4 fractured at the smooth dental neck and 1 atop the central screw), 3 Lifecore implants fractured atop the central screws and 1 Anthogyr implant fractured atop the central screw. Of the 19 patients, 6 had anterior dental implant fracture, and 13 had posterior dental implant fracture (21 fractured implants in total). Maxillary anterior dental implant fracture was observed in 6 patients (8 implants), maxillary posterior implant fracture was observed in 3 patients (3 implants), and mandibular posterior dental implant fracture was observed in 10 patients (10 implants). CONCLUSIONS: A good implant system design, appropriate implant diameter and reasonable upper prosthetic method are key to maintaining long-term stability of a dental implant.

A new approach for cloning hLIF cDNA from genomic DNA isolated from the oral mucous membrane.

Complementary DNA (cDNA) is valuable for investigating protein structure and function in the study of life science, but it is difficult to obtain by traditional reverse transcription. We employed a novel strategy to clone human leukemia inhibitory factor (hLIF) gene cDNA from genomic DNA, which was directly isolated from the mucous membrane of mouth. The hLIF sequence, which is 609 bp long and is composed of three exons, can be acquired within a few hours by amplifying each exon and splicing all of them using overlap-PCR. This new approach developed is simple, time- and cost-effective, without RNA preparation or cDNA synthesis, and is not limited to the specific tissues for a particular gene and the expression level of the gene.

[Analysis of the hard and soft tissue following immediate and early implant placement in the anterior area of maxilla].

Objective: To compare the difference of soft and hard tissue changes between immediate implant and early implant placement in maxillary anterior region, so as to provide the basis for the selection of implant timing and surgical method for patients in clinical maxillary anterior dental esthetic zone. Methods: From January 2016 to January 2019, 89 patients [48 males and 41 females, aged (38.0±13.3) years] with dentition defect and single tooth implant restoration in the Department of Oral Implantology, Dalian Stomatological Hospital were retrospectively collected. The patients were divided into three groups according to different implant timing and operation methods: immediate implant flapless group (26 cases), immediate implant flap group (30 cases) and early implant group (33 cases, early implant 4-8 weeks after tooth extraction). The operation time, intraoperative and postoperative complications were compared among the three groups. Cone-beam CT was taken before operation, immediately after operation and 6 months after operation. The bone plate thickness immediately after implantation, bone plate thickness at 6 months after operation and absorption amount of bone plate thickness at labial side (immediately after operation minus 6 months after operation) were measured, and the absorption rate of labial bone plate was calculated. Three dimensional quantitative analysis was performed on the lip bone increment, residual bone volume (6 months after operation minus preoperative), and bone volume absorption rate of the three groups immediately after operation by using GuideMia, PlastyCAD and Geomagic engineering software. The pink and white esthetic indexes of the three groups were evaluated at 9 months and 15 months after implant placement. The implant stability quotient (ISQ) value was measured at 6 months after implantation, and the patients' satisfaction with the whole treatment process was investigated at 6 months after implantation. Results: The operation time of immediate implant flapless group was the shortest, the median (lower quartile, upper quartile) was 36.5 (33.3, 38.5) min. At 9 months after operation, PES was relatively high [8.5 (8.0, 9.0)], and the final patient satisfaction was 8.0 (7.3, 8.8), and the difference was statistically significant compared with the other two groups (P<0.05). There was no significant difference in the incidence of intraoperative and postoperative complications among the groups (P>0.05). At 6 months after operation, the thickness of labial bone plate in early group was 3.09 (3.00, 3.25) mm, which was greater than that in the immediate non flap group [1.90 (1.72, 2.33) mm] and that in the immediate implant flap group [2.39 (2.05, 3.06) mm], and the difference was statistically significant (P<0.05). The absorption of labial bone thickness in immediate implant flapless group [0.61 (0.35, 0.98) mm] was significantly lower than that in the immediate implant flap group [1.13 (0.97, 1.53) mm] and that in the early implant group [1.23 (1.07, 1.37) mm] (P<0.05). After 6 months, the residual bone volume of immediate flapless group was 38.7 (31.2, 54.6) mm3 and was significantly different from that in early implant group [109.1 (85.6, 263.1) mm3] (P<0.05), and there was no significant difference in the residual bone volume between immediate implant flapless group and immediate implant flap group (P>0.05). Conclusions: Immediate implant can reduce the treatment time with equal esthetic outcome of implant supported restoration of anterior teeth, and patients prefer it more. The bone volume of lip side was not significantly increased after immediate flap operation, and the bone absorption was less after immediate flap operation. Early implant placement can better maintain the three-dimensional bone mass, and the three groups can obtain good clinical results in the short term, but the long-term effect needs further follow-up study.

Further study of the neurohumoral factor, endorphin, in the mechanism of acupuncture analgesia.

Cross circulation was performed between the femoral arteries and veins of paired rabbits that were entirely conscious. Jaw opening reflex by dental pulp stimulation was used as pain index. When acupuncture was applied to the donor rabbit the pain thresholds of both the donor and recipient were elevated from 30 minutes to one hour after acupuncture stimulation and lasted for another 30 minutes after withdrawal of acupuncture. The analgesic effect in both the donor and recipient was abolished by the pretreatment of naloxone. The increase in the pain threshold of the non-acupunctured recipient was due to an opiate-like, humoral substance generated from the acupuncture donor. The possible role of endorphins in the mechanism of acupuncture analgesia is discussed.

Electroacupuncture and laser stimulation treatment: evaluated by somatosensory evoked potential in conscious rabbits.

Tooth pulp generated somatosensory evoked potential (TPSEP) recordings were used to evaluate analgesic responses to Electroacupuncture (EA) and laser stimulation (Ls) treatments in Dutch-hybrid male rabbits. TPSEP recorded 100 trials at 30 minute intervals for 120 minutes. Three groups, EA, Ls and control were analyzed. The EA group received intermittent 4 Hz, intensity 2-10 volts electro-stimulation for twenty minutes. In the Ls group, a gallium aluminium arsenide (GaAlAs) laser diode with wavelength 780 nm, switched pulse frequency 9720 Hz, energy density 0.6 J/point was employed. Both EA and Ls groups received stimulation of the points Ho-ku (LI-4) and Tzu-San-Li (ST-36). Results showed tooth pulp generated noxious stimulation produced a consistent late near-field SEP waveform, which is similar to those recorded in humans and correlated to the sensation of pains, thus confirming that tooth pulp stimulation is a reliable dolormetric index. EA and Ls TPSEP recordings showed decreased peak-wave amplitude in late near-field components. These decreases correlate to analgesia. This technique provides an objective and reliable dolormetric index.

Effect of acupuncture on immunoglobulins of serum, saliva and gingival sulcus fluid.

The present research is a preliminary investigation of the changes of immunoglobulins in serum, saliva and gingival sulcus fluid in response to acute and chronic acupuncture stimulation in 70 volunteers. The acute effect of acupuncture showed that 30 minutes and 24 hours after acupuncture treatment saliva IgA levels were significantly increased in those who had previous low levels of IgA, but decreased in those who had previous high levels. When acupuncture was given daily for 2 weeks, the saliva IgA level was significantly increased, about 20% higher than that of the initial value. The IgG levels in serum and gingival sulcus fluid were decreased at 30 minutes after acupuncture treatment. On the other hand, chronic acupuncture stimulation (daily for 7-10 days) significantly increased IgG levels in both serum and gingival sulcus fluid. The regulatory effect of acupuncture on the immunological function of body defense system is discussed.