3-D Diagnostics for 3-D Treatment

Автор: Boris V. Sheplev, PhD, DDS,
Education Centre DentMaster, Novosibirsk, Russia

A large body of our clinical cases confirms published data on success of endodontic treatment: «more than 60 percents of teeth demonstrate radiological indications of periodontal pathology in some time after successful therapy of root canals» (Weiger et al. // Endod Dent Traumatol. – 1997.– № 13.– P.69-74).

Typically, the cause of such phenomena is the combination of objective (complicate anatomy of root canal system (RCS)) and subjective factors (lack of necessary knowledge, skills, equipment and so on). According to A. Castellucci «90 percents of endodontic treatment failures occur because of incomplete cleaning and obturation of RCS» (A. Casttellucci, 2006) (fig. 1).

It was illustrated in the thesis of J. West, 1974: «…100 percents of endodontically-treated teeth extracted for periodontal reasons had at least one not obturated port from the RCS to the periodont» (fig. 2).

Fig. 1 Inadequate obturation of 46 tooth's RCS, periapical and furcal lesion Fig. 2 Removed tooth with nonobturated areas of root canals
(Brown and Herbranson. Dental Anatomy & Interactive 3-D Tooth ATLAS)

As evidenced by the above, thorough diagnostic examination (including a three-dimensional analysis of the original situation) becomes of particular importance.

Deep division of furcation

Initial situation

The previous doctor wasn’t able to path the root canal of 44 tooth (his conclusion was: obliteration). Root canal lumen in apical one half isn’t observed on the preoperative radiograph.

Fig. 3-4 Preoperative radiographs of 44 tooth
X-ray analysis

It’s hard to believe that the root canal could begin obliterate in direction from apex to crown. Let’s examine carefully the apical third:

Fig. 5 While inspecting the periodontal slot on the both sides of the root we find superposition of 2 roots and overlapping layers of dentin are not allowed to see the root canals lumens

It’s extremely essential to interpret x-ray diagnostics properly. To eliminate possible mistakes it is useful to examine pictures made in different projections (fig. 6):

Fig. 6 Three projections
(Clifford J.Ruddle. Film «Clean, shape and pack»)


RCT of 44 tooth

    The success of endodontic treatment strongly depends on the equipment and tools used by dentist. Application of operating microscope helps «to see what you are doing and to do what you are seeing».
Fig. 7а. Dental Microscope from Carl Zeiss; b. Acsess to deep division of RC in 44 tooth; c. The level of division

The bottom of the pulp chamber is located very deeply (fig. 8) – 15-16 mm from the top of the cuspid!

Fig. 8 Example of deep division of RC
(3-D Interactive Tooth ATLAS)
Radiographic control of the obturation

Root canals were obturated in the Schilder technique of vertical compaction of warm gutta-percha.

Fig. 9 Postoperative radiographs of 44 tooth in different projections.
Notice the lateral irregularity in buccal canal and apical delta in lingual canal
Fig. 10 3D visualization of complicate RC system of lower bicuspid
(3-D Interactive Tooth ATLAS)
Endo-Restorative Continuum

    Success rate of RCT significantly increases with continuous approach in endo- and restorative therapy.

Coronal part of 44 tooth was restored with the help of fiberglass point ENA-Post (HFO) and core material ENA-Cem (fig. 11-12), and was prepared for metal ceramic crown (fig. 13-14).

Fig. 11-12 The core creation
(buccal and occlusive view)
Fig. 13-14 Preparing for MC
crown (buccal and lingual view)
Laboratory and fixation of crown

Fig. 15 Impression, models and MC crown on master-model
Fig. 16 Completed indirect restoration of 44 tooth (buccal and occlusive view)


Secondary Endodontic retreatment

Initial situation

The reason for treatment was the patient intention to make permanent metal ceramic crowns on 16 and 17 teeth (before the visit patient used plastic crowns).
There were some complains of discomfort when chewing or touching the projection of MB apex (fig. 17-18).
Anamnesis: 16 tooth had been endodontically retreated 2 years ago and obturated with Thermafil obturators at the same moment. Core was built with carbon post fixed in palatal root and composite core material. Tooth was prepared for metal ceramic crown.

Fig. 17-18 Panoramic X-ray and detailed fragment. There is something wrong in the area of MB apex
Retreatment. The decision algorithm
  1. X-ray analysis
  2. Clinical situation
  3. Quality of restoration

Since there is no clinic and the restoration is ok, the decision about retreatment of 16 tooth should be made after careful investigation of the lucense area on the X-ray. For this purpose it’s useful either to make several images in different projections or to carry out 3D diagnostics with the help of CT (fig. 19-24):

Fig. 19 GALILEOS, 3D Cone Beam
Imaging System
Рис. 20-21 Different slices of MB root of 16 tooth in different projections
Рис. 22-24 Different slices of MB root of 16 tooth in different projections

Analysis of enlarged fragments of sagital slices:
Lesion (area of decrease density) around MB root apex;
The additional canal lumen in the coronal and medial thirds of MB root;
Unfilled parts of canals in apical thirds of buccal canals.

The decision about the second retreatment of 16 tooth has been made.

According Simon Freedman prognosis for success of primary endodontic retreatment comes to 60-70 percents. While for the second one – only 30-40 percents. (Friedman, Shimon. Evidence-based Management of Persistent Disease after Endodontic Treatment. – August, 2007. – Plenary report, 7-th congress IFEA, Vancouver, Canada).

MB2 localization and RCT

The access to MB1 and DB was made.
Cores of Thermafil obturators were removed mechanically.
The gutta-percha from RC walls and irregularities was removed by dissolving in CHCl3 (chloroform) (fig. 25-28)

Fig. 25-28 Access to MB and DB root canals

Then, mesial groove was inspected with Micro-Opener instrument in palatal direction.
After the withdrawal of dentin layer from medial wall of access MB2 orifice was found (fig. 29-32).

Fig. 29-32 Localization and passing the MB2

Buccal canals were cleaned and shaped with Protaper instruments with irrigation of 5 percent solution of NaOCl, patency of apical foramens was maintained (fig. 33-35).

Unfortunately DB was not passed completely because of the ledge.

Fig. 33-35 MB2, MB1 and DB canals endodontically treated with ProTaper instruments

RC were obturated in the Schilder technique of vertical compaction of warm gutta-percha:

Fig. 39-40 Obturated canals Fig. 41 Building of core
X-ray control
Fig. 42 Postoperative radiograph of 16 tooth:
mesial canals are 3D obturated, each canal has its own apical foramen;
distal canal demonstrates filling down the ledge (it must be sealer)
Fig. 43 3D illustration of similar endo-system (3-D Interactive Tooth ATLAS)


Primary endodontic treatment

Initial situation
Fig. 44 Fragment of panoramic X-ray of 15 tooth Fig. 45-46 Distal cavity

The need for endo-treatment in the case of extensive caries lesion of tooth can be solved by diagnostic studying with CT (fig. 47-50):

Fig. 47 Fragment of panoramic X-ray and sagital section of 15 tooth
Fig. 48-50 Different slices of pulp chamber coronal part:
palatal projection – distal cavity; buccal projection – mesial cavity

Because of 3D study detected aproximal carious cavities affecting the coronal pulp of 15 tooth, endo-treatment is planned.

Basic regulations:
  1. Cleaning and shaping the RCS.
  2. 3D obturation.
  3. Endo-restorative continuum for prevention the reinfection of RCS.
Management of crown part

Removal of softened dentin (fig. 51-53).
Preparation of gingival walls with ultrasonic instruments (fig. 54).
Pretreatment – the restoration of aproximal walls of the tooth (fig. 55-56).

Fig. 51-53 Demineralized dentin is excavating
Fig. 54 Mesial and distal cavities are preparing with ultrasonic instruments
Fig. 55-56 Endo-Restorative Continuum

CT analysis. Horizontal slices at the orifice (one slit-like canal) and the middle (2 canals) levels (fig. 57-60).
RCT. RC of 15 tooth were cleaned and shaped with ultrasonic and NiTi instruments (fig. 61).

Fig. 57-58 Horizontal slices at the orifice level of 15 tooth and
3D visualisation (3-D Interactive Tooth ATLAS): one slit-like canal
Fig. 59-60 Horizontal slices at the middle level of 15 tooth and
3D visualisation (3-D Interactive Tooth ATLAS): 2 canals
Fig. 61 Cleaned and shaped buccal and linqual canals of 15 tooth
Signs of RC fusion
  1. Test with gutta-percha cone
  2. Test with fluids
  3. CT analysis

The possibility of RC fusion affects on obturation approach.

1. Test with gutta-percha cone

The master cone is fitted to one of root canals and the file #10 is inserted into the other canal on full working length (fig. 62 a-b).

Fig. 62 a-b Confluent root canals

2. Test with fluids

During the washing of one of the RC the bubbles may appear in the other one:

Fig. 63 Solution examination

Video: irrigation of buccal canal (molar’s mesial root) → bubbles in linqual canal

3. CT analysis

    Horizontal slice at the level between medial and apical portion (fig. 64-66): second fusion of RC.
    Horizontal slice at the level of 2 mm from X-ray apex (fig. 67-68): second division of RC.
Fig. 64-66 Horizontal slice at the level between medial and apical thirds and
3D visualisation (3-D Interactive Tooth ATLAS): second fusion of RC
Fig. 67-68 Horizontal slice at the level of 2 mm from X-ray apex and
3D visualisation (3-D Interactive Tooth ATLAS): second division of RC
Endo-Restorative Continuum

Fig. 69-70 RC of 15 tooth were obturated in the Schilder technique of vertical compaction of warm gutta-percha; sandblasting the tooth cavity was performed
Fig. 71 Coronal part of 15 tooth was restored with dual-curing composite and enamel was restored with composite material Filtek Supreme
Fig. 72-73 Completed direct restoration of 15 tooth
X-ray control
Fig. 74 Intraoral image and Postoperative radiograph of 15 tooth in different projection:
root canals are 3D obturated, each canal has its own apical foramen;
areas of fusion-division are seen

Below (fig. 75-76) there are presented fragments of profile slices, showing fusion (orifice and apical third) and division (middle third and apex) of 15-th tooth’s RC, as well as an example of similar system from Dental Anatomy & Interactive 3-D Tooth ATLAS (Brown and Herbranson).

Fig. 75 Comparison of 3D diadnostics
and obturation data
Fig. 76 3D illustration of similar endo-system
(3-D Interactive Tooth ATLAS)